u

td

t

> l F lrj trt ) I L J

fs tr o

an an ld c, o.

= o U

504

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES plugs and gaskets ryay_ be used to proteq_t the threaded inserts. The lower side of the cylinder mounting flange and the skirt of the barrel should be protected by a sleeve made high and wide enough to hold the assembly firmly. The booth in which the cylinders are to be sprayed should be equipped with an exhaust fan to diaw off fumes, etc., and should have a small turntable on which the parts may be rotated. 'fhis turntable may be power driven if desired. If the table is rotated by hand, an asbestosmitten must be worn to protect the operator from the flame of the spray torch. Rocker box covers should be held flat while being sprayed. is important that the operator Cautlon-It wear a respirator and goggles while sandblasting and metal spraying. The spray gun should be held approxim4tely six inchei from the work and at an angle of about 15' - 20' to the surface in both directions, so that the area between the fins is effectively coated. Apply a final coat holding the gun at right angles to the surface to insure a goo_dggating on the edges of the fins. The desired thickneis is .003" and the maximum thickness should not exceed .005". Excessively thick coating tends to produce a rough finish and has a tendency to flake off. After spraying, inspect the finish for uniformity and quantity. When cylinders are to be stored after spraying, they should be completely coated with No-Oxide EEE, which may be obtained from Dearborn Chemical Company, New York City, N. Y., or some other similar corrosion preventing compound. Assuming that compressed air (35 cu. ft, of free air per minute at 80 p.s.i.) and sandblast

equipment is available, the following equipment is recommended: Type E Metco Metallizing Unit complete with: 1 _ 11 B & S and rf,, Wire Nozzles 1-11 B&Sandft"Aircaps 1 - Lathe Fixture 1 - Tube Valve Lubricant 1 - Tube Gear Case Lubricant 1 - Complete set of Tools 1 - Instruction Manual Type 2H Gas, Oxygen, and Air Hose Unit Type A Metco Air Control Unit Type 25 Metco Wire Control Unit No. G-10 Metco Oxygen Regulator No. 2G-X40A Gas Regulator Type -No. W Metco Compressed Air Drying Unit 554A, complete with expeller and aftercooler Wilmington - Metco Type SH23 City Gas Compressor complete with Yz H.P., L20-220 Volt, single phase, 50-60 cycle, dust proof motor, gastankrpressure switch, and flash back arrestor. Note-All of the above material is obtainable from: Metallizing Engineering Company, Inc. 2107 41st Avenue Long Island City, New York Note-If

it is desired to use Propane, Hydrogen, or Acetylene Gas (in bottled form) in place of city gas, the gas compressor rs unnecessary.

Fig. 500 shows schematically a typical metal spray equipment set-up.

DETAIL INSTRUCTIONS FRONT (Nose) SECTION-WASP for any reason it Thrust Bearlng Llner-If is neaessary to replace a liner in the front section, the area adjacent to the liner should be heated to a temperature of 200" F.-250' F. (93' C.-121" C.) (see Page 501) and then the liner should be drifted out of the nose. In order to reinstall the new liner, the front section should be reheated to the same temperature and the new liner inserted in position. This operation will be facilitated by chilling the liner with dry ice (COz) prior to installation in the front section. Care should be taken to see that the oil holes in the new liner are in alignment with the oil holes in the front section and that the liner is bottomed properly. This latter condition should be checked by attempting to

JR.

insert a .001" feeler gage between the liner and the case. If it is not possible to insert this gage at any point, the liner may be judged to have bottomed properly. After a new liner is installed, the thrust bearing seating surface and the propeller_oil--transfer riig seatiig surface should be ground. Where it is necessaryto grind the bore of a liner to accommodate oversize oil transfer rings, the same instructions apply as for a standard bore with the only difference being in the size to which the Iiner is ground. To accomplish the grilding, the front section should be bolted to an adapter plate mounted in a lathe. Using a dial indicator, indicate the nose section so that the liner forward face and bore are turning concentrically

505

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES

Fig. 501 -

Installing Valve Tappet Guide -

Wasp Jr.

'fhe bores within .001" full indicator reading. should be ground to the desired diameters with a tool post grinder. The front liner should be ground to such depth that the surface of the iear seating flange for the thrust bearing measures !.2I7" + .002" from the front surface of the liner. In doing this grinding, the parts should be free of grease and oil, and the liner should be dry ground so that the metal particles may be readily removed from the oil ages, ete. After cleaning, polish the bore of the liner with crocus cloth and oil. Valve Tappet Sockets-Sockets may be removed by using the Tappet Ball Socket Puller. The tappet and socket assembly should be inserted into the split bushing so that the bushing clamps around the O.D. of the socket. Secure the bushing firmly between the jaws of a vise, and using the puller, remove the socket from the tappet. An alternate method of removing sockets from Wasp Jr. B and 82 tappets and the nondraining tappets on the Wasp Jr. 83, Wasp and Hornet engines is to drill and ream an .8L35" + .001" hole in a steel block and insert a steel bushing, having a hole with a diameter of .793" + .001", in the lower part of the block. This bushing is necessaryin order to provide a good shoulder to the tappet while the socket is driven out. Place the tappet in the drilled

Fig. 502 -

Reaming Valve Tappet Guide -

Wasp Jr.

hole with the socket down. Then insert a drift in the upper end of the hollow tappet and force the cup out with an arbor press. In order to install a new socket, the cup should be lightly placed in the tappet. Then place the assembly, socket down, in the .8135" r .001" hole in the steel block used for removal and press the socket into the tappet with an arbor press. the draining type tappets, the Note-In tappet ball socket and oil bushing must be assembled prior to insertion in In doing this, make the tappet. certain that the oil hole in the bushing is aligned with that in the tappet. Valve Tappet Guldes-To remove the valve tappet guides it is necessary to heat the front section (see Page 501) after which the guides may be removed with the Valve Tappet Guide Drift. After removal of the guides, the guide holes should be cleaned up with crocus cloth and oil. In the event that a standard size guide will not provide the desired fit, oversize guides are available. When installing oversize guides, the holes in the front section should be reamed sufficiently with a 1912"standard expansion reamer to clean them up. Turn down the tappet guide to give the required fit in the nose section.

506

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES

Prior to installation of a new guide the front section should be reheated and the guide and its retaining hole coated with a suitable grease "No-Oxide-E". The new guide may be such as chilled with dry ice (COz) to facilitate installation. With the aid of the Valve Guide Drift and a fiber mallet, install the new guide so that it is positioned correctly in the case, i.e. so that the slot in the guide is parallel to the cam roller If replacing less than a complete set tracks. of guides, the Tappet Guide Aligning Plate should be placed in the slot of the adjacent guide and the replacement guide aligned by means of this plate. If replacing a complete set of guides, the first guide should be aligned with the slotted Aligning Plug which is placed in the hole adjacent to the guide being installed (seeFig. 501). This plug may be rotated in the nose section until its slot is parallel with that of the guide. Then insert the Aligning Plate in the slots of the Aligning Plug and the guide. After driving home the first guide, the next guide can be aligned from it, and the same procedure followed until all the guides are installed.

The straight reamers are used for taking the primary cuts and the spiral reamer is used in a final operation to clean yq ?ny high spotg which may remain. The straight reamer having the pilot in front of the flutes should be used first and inserted from the outside end of the tappet guide. With this reamer the guide should be reamed to within one-quarter of an'inch from the inside end. The second reamer should then be inserted, handle end first, from the inside end of the guide. The reaming operation should be effected while pulling the reamer out through the tappet guide. Prior to the use of this reamer, the Tappet Guide Reaming Clamp should be installed around the inside end of the tappet gurde to prevent spreading of the guide at the roller slot (seeFig. 502).

The tappet guides should be reamed with the Tappet Guide Reamers. These reamers consist of two straight reamers and a spiral reamer.

Front Breather Assembly-'Should any defects have been revealed during inspection, the complete assembly should be replaced.

FRONT (Nose) SECTION-WASP

Propeller Regulator Valve-If a new propeller regulator valve and shaft assembly is installed, the valve should be lapped into its seat with a fine valve grinding compound. Make sure that all traces of the compound are removed from the shaft and seat before assembly.

Hl AND HORNET E (Dlrect Drlve)

instructions on Thrust Bearlng Llner-For replacing or regrinding, see paragraph with same heading for Wasp Jr. engines. The thrust bearing seating surface should be ground to a depth of L.296" + .002" from the front flange of the thrust bearing liner on the Wasp engine and t.208" + .002" on the Hornet engine. Governor Drlve Gear Bushlng (Wasp Hl)To remove this bushing, drive it from the front section using the Governor Drive Gear Bushing Clean any high spots from the bushing Drift. hole with a standard expansion reamer and, if fitting an oversize bushing, turn down the O.D. of the bushing in a lathe to obtain the desired fit in the nose section. Drive in the new bushing with the Governor Drive Gear Bushing Assemblv Drift and ream it to size with the Governor Diive Gear Bushing Reaming Fixture and Reamer (see Fig. 503). Instructions covering checking and adjusting backlash are given in "Intermediate Goverthe subsequent paragraph nor Drive Gear Bushing". Intermedlate Governor Drlve Gear Bushlng (Wasp Hf )-To remove this bushing, drive out the staking pin and remove the bushing with the Intermediate Governor Drive Gear Bushing Puller. Clean up the hole in the and drive in the new bushing with the Intermediate Governor Drive Gear Bushing Assembly Drift, making sure tbat oil holes are properly lined up. Use the Cam Reduction and Intermediate Gov-

Fig- 503 -

Reaming Governor Driven Wasp H1

Gear Bushing -

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES ernor Drive Gear Reaming Fixture and Reamers for reaming this bushing (see Fig. 504). After reaming the new bushing, the gear should be inserted in position in the intermediate governor drive gear and the should then be bolted in position in the front section. Check the backlash between the two governor drive gears, using a dial indicator. If i-nsufficient backlash is obtained, the intermediate governor drive gear bushing should be faced off the desired amount by mounting the in a lathe and turning off the face of the bushing. replace Cam Reductlon Gear Bushlng-To this bushing, drive out the staking pin with a

507

small steel drift and remove the bushing with the Cam Reduction Gear Bushing Puller. If the br,r,shinghole in the nose section requires cleaning up, an oversize bushing should be used and turned down on the O.D. to obtain the desired fit. Drive the new bushing into the retaining boss and, using the hole in tlge case as a guide for the rf" drill, transfer-drill the staking hole in the new bushing and drive in the staking pin. Ream the hole with the Cam Reduction Gear Bushing Reaming Fixture, Reamer Bar, Roughing Reamer, Finish Reamer and Aligning Check the alignment as Bar (see Fig.505). described in Chapter IV.

FRONT SECTION (Reduetlon Gearlng and Houslng Assembly) wasP El-G, EoRNET E-G, E2-G AND E8-G Thrust Bearlng Cover Assernbly (Hornet ES-G)-The liner in the thrust bearing cover plate is shrunk in and the rear edge spun over after assembly. In order to remove the liner, place the plate in a lathe and face off the spun Surface on-the rear edge of the liner. Then lieat the area of the plate around the liner to 200o F. (93" C.) (see Page 501) and drive the old liner from the plate. The new liner may be pressed into place with the plate at the same lemperature. Care should be taken to see that the flange of the liner is seated on the forward' face of the plate. The rear edge of the liner should then be spun over to form a shoulder on the rear edge of the plate, by trueing up in a lathe to run within .001", full indicator reading, and spinning it over with a spinning tool. The procedure for grinCing old liners to accommodate .005" or .010" oversize oil seal rings is similar to that for grinding a new liner after installation in the cover, with the exception of the difference'in the size of the bore. inspection has reThrust Bearlng Llner-If vealed the necessity of replacing this liner, it should be accomplished as follows: Drift out the thrust bearing cover studs, using a fiber drift. The studs should be driven from the inside of the reduction gear housing to the front. Heat that portion of the reduction gear housing adjacent to the liner to a temperqture of 200dF.-250' F. (93' C.-t2L' C.) (seePage 501) and drive the liner from the nose section. Again heat the case and install the new liner in position, making certain the oil holes in the liner coincide with those in the case and that the liner is properly bottomed. Using an arbor press, reinstall the thrust bearing cover studs, making sure that they are a tight fit in the front section. The method of grinding thrust bearing liners on seared -direct engines is the same as that described drive engines under the heading for

Wasp Jr. engines. The liners should be ground to the desired dimensions with a tool post grinder. Governor l)rlve Gear Bushlng (Eornet OnIy) -This bushing may be removed with the Governor Drive Gear Bushing Disassembly Drift and a replacement bushing installed with the Assembly Drift. Oversize bushings are available and may be fitted after reaming the. hole in the case with an expansion reamer until the required fit is obtained with the replacement bushing. When installing a new bushing it is important that the oil holes line up properly. The new bushing should be reamed with the Propeller Governor Drive Gear Bushing Reaming Fixture and Reamer. After installation of a new bushing, the intermediate governor drive gear should be installed on the bearing plate and the plate should be temporarily fitted in place on the reduction gear housing for the purpose of checking the backlash between the intermediate governor and the governor drive gear. Should drive gear there be insufficient backlash between the governor drive gear and the intermediate governor drive gear, it may be increased by facing the governor drive gear bushing with the Governor Drive Gear Bushing Facing Tool. Flxed Gear-To regrind the fixed gear bore for oversize oil transfer rings, mount the gear in a lathe and indicate so that the runout does not exceed .001" full indicator reading on the forward flange and outside diameter of the centering shoulder; grind to the desired diameter (see Fig. 506). As the I.D. of the ring seating surfa_ceis less than that of the rest of the bore on the Wasp H1-G engine and greater than that of the rest of the bore-on the Hornet E-G series engines, the newly ground surface should be blended with the adjacent area of the bore. Polish the bore with crocus cloth and oil.

508


4

Fig. 504 --- Reaming Intermediate Governor Drive Gear Bushittg -

Fig. 505 -

Reaming Cam Reduction Gear Bushing -

Wasp Hl

Wasp Hl-G

509


Fig. 506- GrindingFixedGearRing Surface Plnlon Cage-Pinion cagehalves are not interchangeablewith one another. In the event it is desired to replace a pinion cage half, the Pratt & Whitney Aircraft, Service Department, should be consulted. gear bushings Plnion Gear Bushlngs-Pinion are removed and installed with the Pinion Gear Bushing Drift and an arbor press. After installation, the new bushing should be bored or ground to size. To make certain that the I.D. of the bushing will be concentric with the pitch diameter of the gear, insert six pins .218" in diameter between the teeth, equally spaced around the circumference of the Beil, fastening them with a rubber band, and temporarily attach the gear to the face plate of a lathe or boring mill with a draw bar. Adjust the position of the gear so that the run-out of the plunger of a dial indicator resting on the pins does not exceed .001" full indicator reading. Then fasten gear permanently with straps and remove bolt from the draw bar. Using a suitable boring bit in conjunction with the lathe or boring mill, bore the diameter to the desired dimensions (seeFig. 507). If grinding is desirable, a K5BE Norton Wheel in conjunction with a Heald No. 50 Grinder with a wheel speed of 13,000 R.P.M. may be used.

Reductlon Drlve Gear-In the event that either the reduction drive gear or the reduction drive gear hub should require replacement, the Service Department of Pratt & Whitney Aircraft should be consulted prior to replacing these parts. Propeller Shaft and Threads-It has been found in some cases that sharp edges at the thread ends of the propeller shaft hub nut and the propeller shaft become crossed or damaged and cause thread seizure. To prevent this, it is recommended where sharp ends exist, that the partial thread be removed from where it starts to a point where the thread is of full depth and section (see Fig. 508). This operation is accomplished by grinding or fiIing the partial threads down to their root diameter and cutting off with a taper of approximately 3f" from the root to the top of the full thread on the propeller shaft threads, and a taper of approximately 3.4" on the nut thread. The edges of these tapers should be rounded with approximately %t" radius and all burrs and sharp edges removed by stoning. replace Propeller Shaft Rear Bearlng-To a propeller shaft rear bearing, the assembled crankshaft should be mounted in a suitable Iathe. A brass or copper sleeve should be fitted over the splines as near the front of the crank-

510


r- CLEAR AWAYINCOMPLETE \ rxneeo uNnL FULL \

\

DEPTH OF THREADIS oenrNeo. RoUND EDGES.

\ T

Fig. 507 -

Boring Pinion Gear Bushing

shaft as possible. With the sleeve pressed in place over the splines, mount the assembled crankshaft in the lathe, chucking the rear main bearing boss and dead cehtering the front end in the beveled face. The shaft should then be indicated at the front and rear main bearing bosses to within .001" run-out, full indicator reading. Turn down the outside diameter of the sleevewhich has been pressedover the splines to insure its concentricity with the main bearing boss. Then mount a steady rest on the O.D. of the sleeve, remove the dead center and hore out the bronze bearing to a thin shell. Care should be taken when boring out the bearing not to damage the shoulder in the shaft against which the rear of the bearing rests. The shell may then be collapsed and removed from the end of the shaft.

Fig. 508 -

Reoperation of Propeller Shaft Threads

Clean up any burrs, etc., which may have resulted from the boring operation, and immerse the front of the crankshaft in oil heated to 350" F.-400" F. (177' C.- 204"C.), for approximately 20 minutes. At the same time, chill the new bearing to be installed with dry ice (COr). The new bearing should then be installed in the shaft, using the Propeller Shaft Rear Bearing Pusher, so that the rear of the bearing rests against the shoulder in the crankshaft. Transfer-drill the staking hole in the bushing with a No. 19 (.166") drill, and, ing the bore of the bushing with a suitable arbor, drive in the staking pin. Mount the assembled crankshaft in a lathe as described previously and bore out the I.D. of the bearing to give the proper clearance with the propeller shaft pilot.

MAIN CRANKCASE SECTIONS cams are Plate Type Carn (Wasp Jr.)-As originally finish ground at the factory to the high Iimit, it is possible to regrind the roller tracks at overhaul provided it is not necessary to grind to a depth in excessof .015". However, as special equipment is required for this operation, cams should be returned to United Airports Division, Rentschler Field, East Hartford, Connecticut, for regrinding. See Chapter IV, under "Cam (Plate Type)" for further information.

Should inspection reveal the necessity for a new cam hub, the cam assembly should be mounted front side down in a suitable holder and the rivets removed. The rivets may be started with a round nose punch, and then pulled from the hub with a rivet puller. Disassemble the hub from the cam with a leather mallet. Inspect the holes and their countersunk areas and clean up where necessary.

511

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES InstaII the new hub on the cam and transfer drill the 35 rivet holes with a #22 (-I57") drill. Break the sharp edgesof the drilled holes on the front of the n-ew Cam hub with a countersink and clean up with emery cloth. Drive in the new rivets and upset the ends on a rlyeting machine or with a round nose punch. Using a surface srinder, grind the rivet ends flush with the rear Surfaceof the cam. Carn Adjustrnent (Plate Type) .It insPection reveals tiat the tappet rollers are riding slightly off center on the cam track, the cam fore and aft position may be adjusted by varying the- thickiess of the crankshaft adjusting spacer located ""aut the thrust bearing. Where it is found ttrat the tappet rollers are riding too far forward ott th" camiiack, the cam may be moved forward by reducing the thickness of the spacer the required amount. In the event that the tappets aie riding too far to the rear on the cam track, lh. .u- -uy be moved to the rear by installing a spacer of increasedthickness. Shelf Type Cam (Wastrl Hl and Hornet E Sertes)-'ihe prece4iry lnstructions relative to regrinciing the cam lobes also apply to the shelf type cam. Cam Otl Feed Bracket (\ilasp Jr.)-Should the short oil feed pipe be loose in the bracket, it may U" iient"ned by sweating solder onto the end of itt. iip. and then scraping the end until the desirbclfit is obtained. Cam Reductlon Gear Bushlng (Wasp Jr.)The replacement of the cam reduction gear bushing should be accomplishedas follows: Using a small steel drift, drive -theistaking-pin from tht bushing. Then, using the Cam Reduction Gear Bushing Puller, remove the bushing from the crankcase. Prior to installation of a new bushing, clean utr anv burrs on the case caused by removal of tie brishing and see that the oil holeg are perfectly clean by blowing out with an air blast. Using the large slotted washer and the thick steel bushing of fhe Cam Reduction Gear Bushing Puller install the new bushing in the case so that the two oil holes are at right angles to the oil Dressure hole in the case. With a LA" drill, transfer-drill the staking pin hole and drill the oil bleed hole into the bushing. Place a steel arbor of sliehtlv less diameter than the bushing in the bushing ind drive in the staking pin. This bushing should not be reamed until the front half of the main crankcase section is assembled onto the engine. To accomplish th!s, place the Aligning Fixture over the end of the crankshaft and align the Fixture by means of the Alienine Bar. The bushing should then be reained-with the Cam Reduction Gear Bushing Reamer.

The atignment of the bushing. aflgr rearnilg should be-checked as described in Chapter IV, "Inspection". Carn Reductlon Gear Bushlng (Wasp and necessaryto replacea cam reduction Ilornet)-If sear bushing, drill out staking pin and remove bushing from caseusi4g the Cam Reduction Gear Bushing Puller, (see Fig. 5-09). In case the desired fif cannot be obtained with a standard size bushing, an oversize bushilg +uy b-eused, turning down its O.D. to give the desired fit with the crankcase. Install the new bushing, placing oil hole 90' from oil hole in case. Drill bushing staking hole and stake bushing. The bushing may the! be reamed using the Cam Reduction Gear Bushing Reaming Fiiture, Reaming Bar, Rough Reamer and Finish Reamer. In gearedenginesthe cam reduction geal bushing in"the bearing Platêis replacedin the same manner as described for the crankcase. However, when reaming, the bushings in both the bearing plate , and front crankcase must be line reamed together with the plate in position on the front crankcase. Reductlon Drlve Gear Bearlng Llner-In the event that the reduction drive gear bearing liner requires replacement, -the bgqti"g plate stuida be mounted under a drill pressat an angle of 60o to the bed of the press. With a Yt6"drili, spot drill the four dowel pins tf" deep. Then *ittt a No. 15 (.180") drill, drill into the dowels. It will be found that in most cases,the shell of the dowel will seize to the drill and will be removed when the drill is withdrawn. If the shell of the dowel does not come out at this time, it should be collapsed and removed. Heat the bearing plate to 350'F. (177"C.) tseePage 501) an-ddrive out the old liner. removing the liner, ascerCautlon-Before tain that the dowels have been completely removed, as the bore of the bearing plate is likely to be damaged should any pieces bf tne dowels be wedged between the liner and the plate. An alternate method of removing the liner is to grind three grooves acrossthe smooth face of the"liner just deep enough to approach the metal of the pl-ate and- then collapse and remove the liner. sure that in grinding, the Cautlon-Make wheel doesnot touch the baseof the plate. To install a new liner, clean up the hole in the plate, reheat the plate to 350" F. -(177"C.) and press in the new litler, Iocating the- dowgl pj" holes 45o from the old holes. Transfer-drill the dowel pin holes with a No. 13 1.185") drill, Vt6" in depth, and drive in four steel p!ls.- The pins shoulh be peened over and filed flush with the liner. Then bolt the bearing plate to

5L2

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES the face plate of a lathe and true up on the front and shoulder until it runs true within .002" full indicator reading. Secure in this position and grind the liner to the proper size. Polish with crocuscloth and oil. Front and Rear Maln Bearlng Llners-In order to remove the front and rear main bearing liners the four dowel pins in their bores should first be removed. Place the crankcase section in a suitable holding fixture with the parting surface down. The mounting surface of the fixture should be at an angle of 60o to the bed of the drill press. Spot drill each pin with a \6" drill approximately Ya" deep. Then, with a ffLi (.180") drill, the dowelsshould be drilled through. It has been found in shop practice that usually the shell of the dowel pin will seize to the drill and come out when the drill is removed. If this is not the case, the shell of the dowel should be collapsedand removed. removing the liners, check Cautlon-Before to determine if all four dowels have been entirely removed as damage to the bore of the case is likely to occur from pieces of the dowel pins being wedged between the liner and the bore of the case. Grind three grooves acrossthe inside face of the liner as deep as possible without touching the bore of the case. These grooves should be equally spaced. Collapse and remove the liner from the crankcase.

Prior to the installation of a new liner, clean the bore of the case and the O.D. of the liner thoroughly to insure good between liner and bore of case. Heat the crankcaseto 250" F.300' F. (121' C.-149' C.) (seePage501) and install liner in its place. torch is used, do not allow flame Cautlon-If to heat section of front crankcasearound valve tappet guides as they are liable to becomeloose and misaligned. Note-Chilling the liner before assembly will simplify installation in the crankcase. When installing new liners, it is recommended that the dowel pin holes in the new liner be located equi-distant from the old pin holes in the case. 1'o insure bottoming the front main bearing liner flange of geared engines in the crankcase, tap the liner with a mallet while the case is cooling. After the casehas cooled, place it in the holding fixture which was previously used for drilling out the old dowels, and transfer-drill four holes with a #LB (.185") driIl Vl6" deep (overall depth) through the liner. Drive in four dowels and rivet them over. On geared engines,the threads in the I.D. of the front liner may become distorted during the shrinking operation. To correct this, the threads should be chased on a lathe or with a suitable hand thread chaser. Note-The size and number of these threads is 6" x 16, U. S. Standard Form, class 3, Ieft hand on the Wasp H1-G and7" x 16, U. S. Standard Form, class 3, left hand on the Hornet E-G series. If this operation is to be done on a lathe it must have a minimum swing of 24" to accommodatethe case. After the liners are installed, mount a Face Plate Adapter (drilled so that the rear main crankcasesection with studs may be bolted to it) on a suitable internal grinder, or a 24" Iathe. Indicate the snap ring to run true within .001" full indicator reading. Assemble the two sections of the crankcase together and attach rear section to face plate. Indicate the front parting face and front O.D. of case to run true within .001" full indicator reading. Finish grind the liners to the proper dimensions. This may be done on a 24" Iathe with a tool post grinder if an internal grinder is not available.

Fig. 509 -

Removing

Cam Reduction

Gear Bushing

Valve Tappet Guldes-To remove the valve tappet guides it is first necessary to remove the guide locking screws on Wasp engines and the guide locking pins on Hornet engines. The case should then be heated and the guides removed with the Valve Tappet Guide Puller. After removal of the guides, the guide holes should be cleaned up with crocus cloth and oil.

513

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES In the event that a standard size guide will not give the desired fit, oversize guides are available. When installing oversize guides, the holes in the case should be reamed sufficiently with a l%2" standard expansion reamer to clean up. Turn down the tappet guide to give the required fit in the crankcasesection. Prior to installation, coat a new guide and its retaining hole with a suitable grease such as "No-Oxide-E". Heat the case to 200" F.250oF. (93' C.-L?L'C.) (seePage 501). With the aid of the Valve Guide Drift and a fiber mallet install the new guide so that it is positioned correctly in the case,i.e. so that the slot in the guide is parallel to the cam roller tracks. If replacing less than a complete set of guides, the Tappet Guide Aligning Plate should be placed in the slot of the adjacent guide and the replacement guide aligned bv means of .this plate. If replacing a complete set of guides, the first guide should be aligned with the use of the slotted plug which is placed in the hole adjacent aligning to guide being installed. This plug may be rotated in the crankcase section until its slot is parallel with that of the guide. Then insert the Nigning Plate in the slots of the Aligning Plug ancl guide. After driving home the first guide, the next guide can be aligned from it, and the same procedure followed until all the guides are installed. After installation, the guides should be locked in place with the tappet guide locking screw or with the tappet locking pin as the case may be. Valve tappet guides should be reamed with the Valve Tappet Guide Rough and Finish Reamers. The Rough Reamer is used to make the first cut and is run completely through the guide. Prior to using the Finish Reamer the Valve Tappet Guide Reaming Clamp should be placed on the slotted end of the guide to prevent it from spreading while being reamed. Then the Finish Reamer should be run through the valve tappet guide. A |rA standard 10 flute straight ieamer may be used to remove any high spots which remain in the guide. Intermedlate Governor Drlve Gear Bushlng (Hornet Englnes)-If it is desired to replace the intermediate governor drive gear bushing, remove the retaining screw and washer. Drift the bushing from the bearing plate. Clean up the hole with crocus cloth and install a new bushing. Should it be desired to fit an oversizebushing, the hole should be reamed with the Intermediate Governor Drive Gear Bushing Reamer. The Intermediate Governor Drive Gear Bushing Reaming Fixture should be used to guide this reamer and the Aligning Bar used to align the fixture. The bushing should be installed from the front of the bearing plate with a suitable drift. It is important to line up the oil holes in the bush-

ing with those in the plate. When properly installed the slot in the bushing and the slot in the plate will be aligned. Install the washer so that the key of the riasher will be inserted in the slots of both the bushing and the bearing plate. Tighten down the washer with the retaining screw. The head of the screw should be staked to prevent it from backing out. to Maln Improved Otl Transfer-Blower Case (Wasp Jr.)-To provide an oil tight seal between the blower and the main crankcase sections, a new method of oil transfer was incorporated in the Wasp Jr. engines starting with engine #279. The ferrule formerly used to transfer pressure oil from the blower to main caseon early Wasp Jr. engines was replaced by a flanged fitting and bracket located inside the pilot of the cases. The former type main crankcase and blower section can be reoperated at the factory to accommodate this improvement if desired. However, on of the special fixtures required in remachining, it is not recommended that this change be attempted in the field. When ordering a new blower or main crankcase section for Wasp Jr. engines, it is necessary to specify the type required.

DRILL AND TAP NO.8-32 NC-3 4- H OLE S

Fig. 510 -

Installing on Sump

Mounting

Disc for Name Plate

5L4

REPAIR AND ÂSSEMBLYOF MAJOR SUB.ASSEMBLIES

Installlng Mountlng Dlsc for Name PlateLater models of the Wasp Hl and Hornet E engines with magnesium sumps use a brass mounting disc to hold the Pratt and Whitney name plate securely. To incorporate this new method of securing the name plate, remove the name plate and all rough edges left on the boss

of the sump. Drill and tap four No. 8-32 NC-3 holes as shown in Fig. 510. Install the mounting disc, being sure to align the wing slots of the disc with those of the sump. Secure disc with four screws and stake securely. Install name plate and peen down the edge of the disc around the plate.

CYLINDERS exBarrel Reconditioning-As Cylinder plained in "Inspection of Cylinder Barrels", Chapter IV, there are limitations on regrirrding cylinders. Special equipment is required for regrinding cylinder barrels and if this is not available, cylinders should be returned to United Airports Division, Rentschler Field, East Hartford, Connecticut, for this operation. Honing of choked cylinder barrels at overhaul is not recommendedas a general practice. Honing tends to decreasethe choke, and usually removes material unnecessarily from the cylinder walls in general. If it is desired to hone as a means of correcting cylinder banel out-of-roundness which exceeds .006", or to remove a step exceeding .006", the Pratt & Whitney Aircraft Service Department should be consulted. Honing should not be substituted for lapping cylinder walls and piston rings, as described elsewhere in this chapter.

Fig. 511 -

Drilling Out Valve Guide

Chrome-molybdenum barrels may be reground straight, although this operation destroys .the choke feature and its advantages,but the regrinding of nitralloy barrels is not recommended. If a step of .006" or more has resulted from wear at the top of the piston stroke (seeInspection Chapter) in either chrome-moly or nitralloy barrels, but the barrel is not worn to the replacement limit, the step may be removed by one of several methods. It is sometimes possible to remove or blend a small step satisfactorily in chrome-molybdenum barrels by simply using a hand stone. Another method is to use a small portable grinder equipped with a small wheel, in which case care musf be exercised to grind only the part of the cylinder wall above the travel of the top _piston ring. One of the most satisfactory methods is to mount the cylinder in a grinder, such as the Heald No. 73 (Red Head) or Heald No. 50, with the barrel enough off center that the stepped portion may be ground without removing much mate-rial from thelest of the top of the barrel bore. When using this procedure, the grinding shoul4 b. done witti a standard grinding wheel which has been undercut for parf of its width, the width of its remaining standard diameter being a-pploximately the same as the part of the barrel which extends beyond the upper end of the top ring travel. After the step-has been removed, the reground surlhce should be blended with the adJacent part of the cylinder wall as well as possible. Still another method is to use a tapered grinding wheel which conforms to the angle bf the choke, iemoving the same amount of material all around the top of the barrel bore until the step has been eliminated. The grinding wheel should then be manipulated in such a way as to blend the reground surface with the adjacent part of the cylinder wall. For service operations, the followlng cylinder barrel regrinding equipment has been found satisfactory. Heald No. 73 (Red Head) Grinder with Norton 3860-I8BE (for Chrome-Moly barrels) or Norton 3?60-I (for Nitralloy barrels) grinding wheel turning at 4600 to SZOOR.P.M. with a chuck speedof 280 to 360 R.P.M. Heald No. 50 Grinder with same grinding wheel turning at same speed as Heald No. 73, and with

AID


Fig. 512 -

Reaming Valve Guide

arm of grinder turning at approximately 75 R.P.M. Bryant No. 24 with same grinding wheel and samewheel and chuck speedas Heald No. 73. The grinding fluid recommended for use in conjunction with the Norton Wheel is No. l4l International Chemical Compound, manufactured by the International Chemical Company of Philadelphia, Pa. Under no circumstances attempt to grind cylinders dry. When determining the proper oversize to which a chrome-molybdenum eylinder should be ground, the diameter of the cylinder at the point of greatest wear should be taken. Add .002" on either side or a total of .004" to the present cylinder bore to allow for cleaning up, and grind to the nearest oversize above this diameter. When grinding, cuts of .001" may be taken at first, gradually decreasing the amount as the desired oversize is approached. The last cut of the grinder should remove a negligible amount as it es through. This technique should provide a smooth satin finish, free from heavy grinding marks or scratches. remove a valve guide, the Valve Guides-To cylinder should be mounted on a suitable fixture under a drill press. Using the proper Valve Guide Drill, drill out the old guide to a thin shell, inserting the drill from the valve spring end and drilling to within approximately rA"

Fig. 513 -

Removal of Inlet Valve Seat -

Boring

of bottom of guide (see Fig. 511). When the drill esunder the shoulder of the valve guide where there is an undercut, the head of the guide may be removed from the valve spring end. Insert the proper Valve Guide Drift, and drive out the remainder of the guide towards the valve seat. After removing the old guide, check the hole in the cylinder head for damage and out-of-round condition, particularly at the bottom. If necessary to clean up the hole in the cylinder head, it should be reamed oversize with the proper Valve Guide Hole Expansion Reamer. The hole should be enlarged only enough to make it round, and the O.D. of an oversize guide should be turned down to obtain the desired fit in the cylinder head. Heat the cylinder head to about 2A0"F. (93' C. ) (see Page 501-). Smear the guide with a light coating of oil and graphite and install in position using the proper Valve Guide Drift. After installation, the guide should be reamed to size with the proper Valve Guide Reamer, (see Fig. 5L2). Subsequent to reaming, the guide should be checked with the proper Valve Guide Plug Gage. remove the bronze Bronze Valve Inserts-To inlet valve seat inserts, mount the cylinder on an angle plate in a lathe or drill press in such a way that the centerline of the valve guide is in

516


Fig. 514 -

Fig. 515 -

Facing Valve Seat

alignment with the chuck of the machine being used. Using the Valve Seat Remover, bore out the old valve seat (see Fie. 513). This tool consistsof three cutters for the Wasp and Hornet engines and two cutters for the Wasp Jr. engine. The first cutter removes the major part of the insert, the others take light cuts which reduce the insert to a thin shell which may then be removed by collapsing with a sharp tool. No attempt should be made to remove the old valve insert by driving or pulling, as aluminum tends to adhere to bronze and damage to the cylinder head may result. Heat the cylinder to approximately 400" F. (204" C.) and, using the Valve Seat Holder, install a new seat in the cylinder head. care to prevent the cylinder Caution-Take head from turning on the banei when it is hot. After installation, the seat should be resurfaced so that the proper valve seat angle and surface are obtained. The resurfacing of valve seats should be done at every overhaul, regardless of whether or not the inserts have been removed. It is important, however, that the valve guides "bellare in good condition and not excessively mouthed." Otherwise new guides should be installed before facing the seats. There are three kinds of cutters provided for the Wasp and Hornet engines and two for the Wasp Jr. The Valve Seat Roughing Facer is

Refacing Valve

used for taking the first cut and the Valve Seat Finishing Facer is used for further cleauing up the seat. It is important to seethat the valve seating surface on the insert is slightly narrower than that on the valve. The third cutter on the Wasp and Hornet enginesis a 35' Relief Facer and is used for cutting back the seats (see Fig.

5r4).

It is possible to reface bronze valve seats by grinding. Rough and finish grinders suitable for this operation are on the market and may be used in conjunction with any suitable powerdriven tools such as those recommended under "Steel Valve Seat Inserts". The rough wheel is used just enough to obtain an evenly ground surface the full width of the seat and is followed by the finish wheel. The latter wheel is used to insure smoothnessof the seat's surface. Whichever method is used, care should be exercised to see that no more metal is removed from the seats than is necessary to accomplish the desired results. is exExhaust Valve Seat-Replaeing-It pected that the steel exhaust valve seat will last the life of the cylinder and will not need replacing. If experienceshould prove that these seats need replacing, the cylinder should be returned to the factory, or special instructions for doing this work will be issued by the Service Department. Refer to the Inspection Chapter for determining when seat replacement is necessary.

5L7

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES Steel exhaust valve inserts should be ground to obtain a true surface. Special equipment for grinding these seats may be obtained from the following manufacturers : Black & Decker Manufacturing Co., Towson, Maryland, Van Dorn Electrical Tool Co., Towson, Maryland, Albertson Manufacturing Co., Sioux City, Iowa, Wadell Engineering Co., Newark, N. J., HaIl Manufacturing Co., Toledo, Ohio. The first three named companies manufacture light equipment of the concentric grinding type. The fourth company manufactures a heavy shop or manufacturing machine of the eccentric grinding type. The last named company manufactures a light portable grinder of the eccentric grinding type which may be used for both exhaust and inlet seats. The same wheel is used for both seats. The steel insert is very durable and requires No more metal very little reconditioning. should be removed than is necessaryto clean up the seating surface of the insert. In cleaning up the surface, it is not necessaryto remove small isolated dark spots entirely, particularly if they are not at the edge of the valve seating area. The valve seating surface should be slightly narrower than the corresponding surface on the valve. The width of the surface on the inserts may be reduced by cutting with a wheel dressed to 35o. However, they should not be more than .020" narrower than the valve face width. seating surfaces of the Valve Refaclng-The valves should be dressed on a valve refacing machine at each overhaul (see Fig. 515). The refacing machine should be set for an angle-cut ofexactly 45". The most important factor in the use of the above machines for grinding the valve surface is in the proper dressing of the grinding wheel to insure the accuracy of the 45" face angle and the desired condition of the ground surface. The wheel should be run across the valve surface evenly and only enough material should be removed to clean up the surface. This is particularly true on the exhaust valve, as the stellited coating is relatively thin and it is desirable to retain as thick a coating as possible. When it has become necessary to reface an intake valve to the extent that a knife edge has resulted at the outer periphery of the head, the valve should be replaced. An exhaust valve should be replaced when there are indications that it has been refaced to the depth of the stellite face, which averages about .040" in thickness. The following companies manufacture machines suitable for this purpose: Black & Decker Manufacturing Co., Towson, Maryland, Cedar Rapids Engineering Corporation, Cedar Rapids, Iowa, Albertson Manufacturing Co., Sioux City, Iowa, Van Dorn Electrical Tool Co.,Towson, Maryland, Hall Manufacturing Co., Toledo, Ohio.

will be found that if valve Valve Lapplng-It seats are properly resurfaced and the valves accurately ground, very little lapping of the valve will be necessary to insure a good seal. Place a small amount of lapping compound, Clover 2A or its equivalent, on the seating surface of the valve, and insert the stem of the valve in its gurde. Care should be taken to see that no lapping compound is allowed on the valve stem. Using the Valve Lapping Tool, lap the valve with an oscillating motion, Iifting the valve every few turns to a new location, until it can be felt that the lapping action has ceased. Remove the valve, wipe off the compound and examine the seating surface to determine if it has a dull satin finish all around. After lapping, Prussian Blue may be used to determine if the valve is seating properly, or the sealing efficiency may be checked by partially fi.lling the cylinder with gasoline while the valves are in place, and noting whether any of the gasoline leaks through into the ports. Wash thoroughly to remove all trace of the lapping compound. Spark Plug Bushlngs-'Spark plug bushings in mbst casesmay be removed with the Spark Plug Bushing Remover. However, in some cases it may be necessary to mount the cylinder on a drill press and counterbore the bushing with a t pilot and a Lyr6" diameter cutter. Make ,{ 6drtain that the counterbore is centered in the spark plug hole during this operation. With a hack siw 6tade, cut thiough tlie remainder of the bushing in two places about rf" apart, using great care not to saw into the threads of the cylinder heads. Drive out the small segment and collapse the shell. If necessary,the threads in the casting may be cleaned up with the Spark Plug Bushing Taper up onlv eno.ugh enoush to clean up Insert tJtq. the tup tap otly Tan. Insert T"p,. the threads. A Iight cutting oil should be used to lubricate the tap. The new bushing may be installed with the Spark Plug Bushing Pusher. This bushing has a Ieft hand tapered thread on the outside diameter. The threads should be covered with grease, and the bushing screwed into place with the pusher. After installation, a sharp blow of the hammer in the reverse direction will break the pusher loose from the bushing. Face off the inner and outer ends of the bushing using the Spark Plug 'Ihe inside should be faced Bushing Facers. head and the outside cut cylinder flush with the back enough to make the finished thickness of the bushing r/2" ott the Wasp and Wasp Jr. and 3,/+" on the Hornet. After this operation, tap out the bushing with an 18 mm. tap. order to replace the Roeker Shaft Inserts-In rocker shaft inserts, the section around the insert hole should be heated to 250" F. (121'C.) (see Page 501) and the inserts drifted out. Rocker Shaft Insert Drifts are available for this

518

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES operation. To install new inserts, reheat the h-ead and drift them into place. These inserts are line reamed with the Rocker Shaft Insert Reamer. This is a stepped tool and reams both inserts at the same time (seeFig. 516). Rocker Arm Ball End Socket-To remove the baII end socket, drill a rf" diarneter hole in the top of the rocker directly over the cup. Be careful not to force the drill too deep on the rocker ball cup. With a punch drive out the old cup. Countersink the drilled hole on inside of rocker with the point of a large drill to remove any burrs. PIug the drilled hole with a piece of ttght fitttng brass and peen over at both ends to secure. Make sure the plug is flush on the inside. Press the new cup into place with the oil hole lined up with the agein rocker. The hydraulic Rocker Arm Ball End Socket Disassembly Fixture may be used for this operation if available. To use this hydraulic tool, plug the oil hole in the worn cup with a tapered steel pin and place the rocker arm in the tool (seeFig. 5I7). The agesin the tool should then be filled with heavy oil, expelling the air from the ages. Give the plunger of the tool a sharp blow with a heavy hammer which will expel the socket from the rocker arm. As the socket is ejected with considerableforce, it should be covered with a heavy cloth to prevent it from causingany damage.

Push Rod Tube Packlng Glands-The push rod tube packing glands contain right hand threads and are screwed into the head casting cold at the time of manufacture. If necessary to replace in case of leakage or damage to the threads, a Push Rod Tube Packing Gland Puller is available for removing a gland. A new gland may be installed with the Push Rod Tube Packing Gland Pusher. Replacement glands should be .004" oversize to insure a tight fit and prevent oil leakage. Push Rod Ball Ends and Spacers-Ball ends may be replaced once, but it is not feasible to use the same set of tubes for a third set of ball ends. The ball ends may be removed by placing the rod in a soft jawed vise and driving the ball end from the rod with a tool shaped to fit the contour of the rod (seeFig. 518). The push rod may be lengthened by placing ONE spacerunder the ball end. Only one spacermay be used under a ball end, but it is permissible to use spacers at both ends of the rod. New ball ends are pressed on the rod with an arbor press. Each spacer is .040" thick and will change the position of the valve adjusting screw approximately one and one half turns. L'he proper position of the valve adjusting screw is from one thread minimum to five threads maximum projecting beyond the locking nut, and the length of the push rod should be so adjusted as to have the screw in this position. Less than one thread projecting from the locking nut will not give adequate locking. More than five threads projecting from the locking nut will cause misalignment of the oil agesin the rocker arm and the valve adjusting screw. Cyllnder Barrel Flanges-The cylinder barrel flanges should be lapped to a perfectly flat surface on a surface plate having a hole which will accommodate the skirt of the banel (see Fig. 519). Refer to Chapter IV for inspection of cylinder barrel flanges previous to lapping. Push Rod Cover Tubes-To prevent partial collapse of the push rod cover tube ends and subsequent oil leakage, steel ferrules are used in the ends of the push rod cover tubes. This improvement can be made on the older push rod cover tubes as follows: Each tappet assembly should be taper-ground on the cup end as shown in Fig. 520. On the upper end of the push rod covers, the lip which is formed inward should be removed so that a ferrule may be installed. This may be accomplished by cutting off the lip in a lathe.

Fig. 516 -- Reaming Rocker Shaft Inserts

A ferrule should be pressed in place at each end of the push rod cover. Then lightly stake the covers, to preclude any possibility of the ferrule becoming dislodged in case of loosening. One staking operation at each end of the cover assembly will be satisfactory. When staking the covers care should be taken not to puncture

REPAIR AND ASSEMBLY OF IVIAJOR SUB.ASSEMBLIES

Fig. 517 -

Removing Rocker Arm Ball Cup

them. Fig. 520 shows the exact position of these ferrules and where they shoultl be staked, as well as the angle of the taper on the tappet assemblies. Cautlon-If it is found necessary to replace a tappet cup socket on engines having reinf,orcedpush rod covers, it is important tf,at the diameter of the replacement sbckets does not exceeda%a". Rocker Box Covers (Wasp Jr. 82, 88, Wasp -covers and Hornet)-Rocker box should 6e faceh off on a lapping plate with a small amount of lapping compound. This precaution is to insure that the cover will bear evenly on the gasket, thus preventing oil leakage. Be sure that the covers are washed thoroughly to remove all traces of the lapping compound. Inter_-cyllnd_er and Inter-ear Draln PlpesAry damaged or bent pipes should be replaced Fy new pipes. Loose pipes should be tightened, but unnecessary tightening should be avoided as it might result in cracked cylinder heads. fntake Plpes and Push Rod Cover TubesIntake pipes and push rod cover tubes should have any dents and scratches removed. Repaint wherever necessary.

519

Fig. 518- RemovingPushRod Ball End Exhaust Port Llner Replacernent (Wasp and Eornet)-The removal of the exhaust port Iiner may be accomplished with the Exhaust Port Liner Puller. To use, insert it in position and heat the area of the cylinder surrounding the exhaust port and withdraw the liner from the head. Clean up the bore of the exhaust port and, using a suitable drift, install the new liner in the head while it is still hot. It is important that the replacement liner be well seated in the head while the metal is still hot. Spare Cyltnde_Ig-Cylinder assemblies shipped as spares for Wasp H1 and Hornet E s-ei{es engines, will have the rocker box cover studs shipped loose to enable the operator to install cap screws or.qtuds depending where the cylinder is to be installed. Cap screws must be rised on the rocker box adjacenl to the sump on cylinders Nos. 5 and 6. When a used cylinder is chosen for Nos. b or 6 location and has previously had studs installed, it will be necessary to remove the studs from the aforementioned rocker boxes and use oversize cap screws.

520


REMOVE THIS LIP

STAKE AS INDICATED TO HOLD SLEEVE tN POSITION.

y9282 PACKtNGI rt4096

1go--------J

(ulcnrrue ro Mrss i.o. or coven)

Fig. 519

Lapping

Cylinder

Barrel Flange

Fig. 520 -

Valve Tappet Reworking

PISTONS AND PISTON RINGS Plstons-In the event that it was found necessary, at inspection, to install overwidth piston rings, the piston ring grooves should be recut to the size necessary to afford the desired side clearance. When recutting a top piston ring groove, most of the material should be removed from the top of the groove rather than from the lower side. It is also important to maintain the radii at the bottom of the grooves. of piston rings to Plston Rlngs-Grinding obtain the desired side clearance is not recommended as a general rule due to the possibility of distorting the ring. In some cases,however, it will be more practicable to remove a small amount of material by grinding rather than to recut the grooves in the piston. If this becomes necessary, it is important that the grinding be done on a magnetic chuck surface grinder taking very tight cuts to prevent excessiveheating with resultant distortion of the ring. When grinding a tapered ring, the grinding should be done only on the top of the ring, as otherwise the ring's scraping edge will be destroyed and the efficiency of the ring reduced. It is suggestedthat a carborundum Aloxite Wheel 50-L or the Norton 1906-L be used. For best results the wheel should have a speed between 5,500 and 6,000 surface feet per minute. It is not posslble to grlnd wedge-type rlngs ln the ffeld. End or gap clearance may be determined by inserting the piston ring in a Master Ring having

a diameter equivalent to the standard cylinder bore (see Fig. 52L). Then, using a feeler gage, the gap may be determined. If necessary to increase the gap, it may be accomplished with a fine file. Where master rings are not available, the bore of the cylinder may be used in the same manner. Remove any sharp edges of the ring which may have resulted from the filing. Later engine models incorporate an improved type piston having wedge-type rings in the three upper grooves. This new type piston and ring assembly is directly interchangeable with the former type and does not have to be changed in complete sets in an engine. Note-Refer to Page 409. "Inspection" for method of checking side clearance of wedge-type rings. Figures 520A and 520B show piston ring arrangements recommended for the various engine models. Rfngs tn . Cylinders-To I,apptng Ptstol insure proper seating during engine run-in, piston rings should only be lapped in the cylinder barrel in which they are to be installed. The number of strokes required for seating rings properly varies with the method employed and the consistency of the lapping compound. Therefore, it will be necessary for each operator to develop the proper technique for the equipment and method he is using.

52L


PIS TON R IN G A R R A N GE ME N TS WASP JR. WITH WEDGE-TYPE RINGS AND CHROME MOLYBDENUMSTEEL CYLINDER BARRELS. SIDE

W A S P JR . W ITH W E D GE -TY P E R IN GS A N D N ITR A LLOY S TE E L C Y LIN D E R B A R R E LS . SIDE CLEARANCE

END GAP

CLEARANCE

ENO GAP

.o5r5-.0585

.o02-.OO4

.05t5-.0585

.o02-.OO4

.o5r5-'0565

'o02-.OO4

o5r5-.o585

.OO2-.OO4

.o5t5-.0585

.OO2-.OO4

.05r5-.o585

.OO2-.OO4

. o5r 5- . o5 8 5

o5t5-.o585 .oo35-0065

. o5r 5- . o5 8 5

.oo35-0065

.o5t5-.o585

.o5r5-.o585

.oils -.0185

.oot-.oo3

.OOl-.OO3

FEELER GAGE

WASP JR. WITH STRAIGHT-SIDEDRINGS AND NITRALLOY OR CHROME MOLYBDE NUM S T EE L C YL IN D E R B AR R E L S .

END GAP

SIDE CLEARANCE

.o515-.o585

.o07-oo9

.05r5-.o585

oo5s-.oo75

.o5t5-.O585

.oo3-.oos

.o5r5-O585

.oo35-0065

.o5r5-.O585

.oil5-.O185

THIS FACE/SHOULD BE FLUSH WITH THIS SURFACE/WHENMEASURING SIDE CLEARANCE OF WEDGE.TYPE RINGS.

LEGENDc - S T R A I G H T C O M P R E S S I O NR I N G - CW -coMPREssloN RING-wEDGE-TYPE TCW -TAPERED COMP RING.WEDGE.TYPE D O -DUAL OIL CONTROL RING S -SCRAPER RING TC -TAPERED STRAIGHT COMP. RING

.oor-.oo3

Fig. 520.4'-

Piston Ring Arrangements (Wasp Jr. Engines)

522


PISTON RING ARRANGEMENTS

WASP WITH STRAIGHT-SIDED RINGS AND CHROMEMOLYBDENUM STEEL CYLINDERBARRELS.

END GAP

SIDE CLEARANCE

H OR N E T W ITH W E D GE -TY P ER IN GS A N D N ITR A LLOY S TE E L C Y LIN D E R B A R R E LS . SIDE CLEARANCE

END GAP

'0665-.O735

.oo7-.oo9

.o7r5-.o785

.oo2-.o04

o665-.O735

o o 5 -.o o 7

.07t5-.o785

oo2-oo4

o665-O735

.o o 3 -.o o 5

.o7t5-.0785

oo2-.oo4

.o665-.o735

oo35-oo55

.o145-.o215

oo35-o055

o035-.0065

.0265-O335

.o o r-.0 o 3

FEELER GAGE

HORNET WITH STRAIGHT-SIDEDRINGS A ND NI T R AL L OY S T EE L C Y L IN D ER B A RRE LS.

END GAP

SIDE CLEARANCE

T H I S F A C E /S H O U L D BE FLUSH WITH THIS

.o7t5-.o785

.o085-oto5

URING SIDE CLEARANCE OF WEDGE.TYPE RINGS.

'o7r5-o785

.0065-oo85

.o7t5-o785

oo45-.o065

.o665-.O735

oo35-.o055

or45-o2r5

.oo35-oo55

Fig. 5208 -

LEGEND-

RING c-srRArGHT COMPRESSION TYPE cw-coMPREssloN RING-WEDGETYPE TCW-TAPEREDCOMPRING.WEDGEDO-DUAL OIL CONTROLRING S-SCRAPER RING TC-TAPEREDSTRAIGHTCOMPRING

Piston Ring Arrangements (Wasp and Hornet Engines)

523

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES The amount of lapping is judged by the condition of the ring surface rather than the inside surface of the cylinder. The compression rings should be lapped until the original tool marks on the outsid-e surface have practically disappeared and the surface assumesa smooth satin frnish around the periphery of the ring. If a ring does not appear-to ha-vea true surface after the usual amount of lapping, the ring should be discarded and a new ring used. With the lapping machine illustrated (see Fie. 522), a satisfactory ring condition may be obtained for the various type rings with the proper number of strokes as shown in the following table Duar oil, Scraper and Cornpresslon Tapered Type of Barrel 30 to 50 200 Nitralloy 15 to 25 100 Chrome-Molybdenum The lapping compound used for this oper,ation is Clover 2A diluted with keroseneand a little oil. The lapping compound should be used sparingly and coarse compounds avoided. It is common practice to use a discarded .010" oversize piston for holding the 1ings. In some casesa special plug is made up for the purpose. In any case, however, a lapping piston should

have a guiding skirt equal in length to the skirt of the conventional piston. A piston or plug should not be used after its diameter is reduced to a point where the piston is a sloppy fit in the cylinder or where the ring grooves have worn excessively, as qgch will not hold the piston rings in proper alignment for Iapping an-dthe ring will tilt back and forth with e"ch s"troke, thus causing the rings to become crowned. It is immaterial whether the rings are held in individual grooves or held in a common groove as long as they have no more side play fhan is necessaryto allow them to expand io fhe cylinder walls. If a lapping piston having a groove wide enough to accommodate all compression rings or the tapered and oil control iings, is employed, fittings rings should be usedto control tho side clearance of the rings in the groove. During the lapping operation, _tb. valves should be in place in the cylinder, and durilg the subsequent washing operation, the cylinder shoulcl be held in the vertical position and every effort made to remove all trace of the lapping compound without permitting any_of it to be washedup into the head of the cylinder. After lapping, any feather edgesthat may have resulted should be removed with a fine stone, being careful not to form a radius on the edge of the ring.

CRANKSHAFT AND ARTICULATING

ROD ASSEMBLY

has shown that little Crankpln-Experience or no wear ts rrrcurred on the crankpin with the use of leaded silver master rod bearings. The crankpin, however, may become scratched or scored by foreign particles entering with the pressure oil. It is usually possible to remove these scratches by such a method as coating the crankpin with cutting oil, wrapping a long strip of old-and worn No. 240 emery cloth once around the crankpin, and, by pulling alternately on the ends, cause the cloth to rotate around the crankpin. A final polish may be obtained by repeating the operation with ciocus cloth and oil. If inspection has revealed the necessity- of lapping fhe crankpin, it may be accomplished as follows: Assemble crankstiaft front and rear sections toeether and mount the assembly in the Crankstrift Holding Fixture fitted wiltt -thg proper Adapter. Plug the crankpin oil holes with heavy grease 6r wax and imear the crankpin surfalein'itft a very fine lapping compound. It is most important to use u "*V fine-grade of compound, as damage can be done to the crankpin if too coarse a -grade is used. With the lap ietaining screws loose, install the Crankp.in Lappine" Tool on the crankpin and adjust the tension"of the lap collar so that t[9 Lapping Tool mav be turnea witfr one finger. This adjustment strould not be so tight thaf a pressureis required

Fig. 521 --- Checking

End

Clearance of Piston

Ring

524


Fig. 522 -

Cylinder and Piston Ring Lapping Machine

to turn the tool, nor should it be so loose that it can be spun easily. When the adjustment of the collar has been completed, tighten the lap retaining screws. Revolve the Lapping Tool and, at the same time, work it back and forth over the Iength of the crankpin. When the Lapping Tool begins to turn freely, the crankpin should be cleaned and measured with a micrometer for out-of-round and taper. If the measurements indicate that the out-of-round or tapered condition still exists, the lapping should be continued for a period of time and measurements again taken. Measurements should be taken in at Ieast four different positions to obtain the exact diaineter. After lapping is completed, remove all compound and polish the pin with crocus cloth and oil. An improper lapping procedure may aggravate the out-of-round condition and may produce a taper on the crankpin. The tool should be oscillated back and forth and at the same time slowly revolved around the crankpin in order to Iap uniformly. To prevent the parting surfaces of the laps from ing each other as the bore of the laps wear, they should be lapped down on a surface plate. Lap these faces parallel, so that il bV chance,the laps touch, they will not be thrown offcenter. leaded silMaster Rod Bearlngs-"Prefitted" ver master rod bearings are supplied on the sub-

ject engines, and are directly interchangeable with the bearings used in early models. They require no boring or fitting to individual master rods. The shape and tolerances of "prefitted" master rod bearings are held to extremely close limits and when being assembled in the master rods should in no way be altered. Cautlon should be exerclsed, durlng handllng and assernblltg, not to dlsturb the Iead coatlng of the bore. Due to the relatively wide spread of allowable clearance between this type of bearing and the crankpin, the standard size is satisfactory for normal replacements and will be supplied for spares unless otherwise specified. Where crankpins have been lapped to the extent that a standard size bearing does not give the desired clearance,a .002" undersize bearing is available. In exceptional cases where the crankpin has been reground to a size where the above bearings do not give the recommendedcrankpin clearance, special bearings will be furnished on request. In this latter case, it is essential that the diameter of the crankpin, not the bearing bore, be specified. An approved method of removing a master rod bearing is as follows: Mount the master rod under a heavy duty drill press or milling machine, or in a boring mill. The bore of the master rod should be ac-

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES curately centered by the use of a dial indicator. Using an eccentric boring tool, bore out the master rod bearing until only a thin shell reto cut into the bore of mains, using great care not 'fhe bearing can be rethe master rod, itself. moved from the master rod by hand, or by tapping it lightly, after it has been reduced to a thin shell. An alternate method of removing a master rod bearing is to make two cuts in the bearing about rf" apart and just deep enough to cut into the steel back of the bearing. Caution-Extreme care must be exercisednot to cut into or damagethe master rod. Remove the small section, then collapse and remove the remainder of the bearing. With the bearing removed, the bore of the master rod should be measured. It is well to reinstall the knuckle pins in their holes as the press fit of the pins is apt to affect the rod bore measurements slightly. If enlarged so that a new standard size bearing will not give the proper fit, the master rod should be reground to the nearest oversize. This is normally a factory job and rods should be returned to the United Airports Division, Rentschler Field, East Hartford, Connecticut, for reoperation. The bore of the master rod should be magnafluxed whenever a bearing is removed. It is recommended that the bearing be removed and the rod bore magnafluxed at about 2500 hours whether or not the bearing requires replacement. See Chapter IV for nrethod of Magnaflux Inspection. To install a new bearing, first heat the master rod in an oil bath to 425oF'.-450o F., (218' C.232 C.) preferably keeping it to the higher limit. Next, put the bearing in position on the Master Rod Bearing Assembly Arbor. It is well to put a piece of paper between the arbor and the bearing to protect the soft lead surface of the latter. Tighten the handle lightly to avoid difficulty in removing it after the heat expands the bearing, and chili both the bearing and the arbor with dry ice (COr). The bearing should be assembled with the flange at the rear side of the master rod. After heating for twenty minutes, remove the rod from the tank and allow the surplus oil to drain from it. Quickly press in the new bearing by hand (see Fig. 523). Due to the length of the bearing and its tightness in the rod, it is important that the bearing be pressedin as rapidly as possible. The bearing must be started straight with the slot in the flange perfectly aligned with the lug on the master rod, and pressedhome so that the flange of the bearing seats firmly against the face of the master rod. After the master rod has cooled down to approximately room temperature, put the master rod and bearing under an arbor press

525

and, using the same arbor as for installing the bearing, press the flange of the bearing against the master rod. This is necessary due to the fact that when the bearing cools there will be a slight clearance between the bearing flange and the master rod. Knuckle Ptrrs-At overhaul, knuckle pins and knuckle pin holes should be cleaned up and polished. All traces of galling should be removed from the knuckle pin holes. Any score marks on tlrg pins and holes should be cleaned up by polishing off the high areas enough to obtain an even surface. Mount the knuckle pins in a Iathe and polish with crocus cloth and oil. The holes in the master rod may be cleaned ,rp with a flexible shaft polisher, or with crocus cloth and oil. The cleaning and polishing of knuckle pins and knuckle pin holes is likely to affect the fit of the pins in the holes. The fit of each knuckle pin in the master rod should, therefore, be chec[ed after these operations have been completed. Measurements of the pins should be made with a micrometer and of the holes with a telescopic gage. Knuckle pins and knuckle pin holes are graded and marked with relation to their sizes. Each knuckle pin and each hole in the master rod has a letter designation. A, B, and C designate standard size knuckle pins, and D, E, and F are used where oversize pins are necessaryto maintain the desired fits. The sizes varv in steps of .0003". The knuckle pins and knuckle pin holes should be of the same classification size. If it is found that one end of a knuckle pin hole varies in classification size from the opposite end, the diameter of the smaller should be increased so that the classification of both ends is the same. When the holes vary by one or two sizes, this may be accomplished by lapping; otherwise the holes should be honed. The number and classification sizes should be etched on both the pin and the master rod. When classification sizes are changed the etched letter should also be changed. Replacement knuckle pins for Wasp and Hornet qngines are now made from nitralloy steel. These pins are directly interchangeable with_the previous type and may be identified by the Number "249" stamped on one end. Replacement.l
526


Fig. 523- Installationof Platlng Knuckle Plns-To provide an antigalling surface and to prevent picking up at assembly and disassembly it is recommended that chrome vanadium knuckle pins be flash tin plated and nitralloy knuckle pins be flash copper plated at the time of overhaul. Nitralloy pins "249" stamped may be identified by the number on one end. Before plating, knuckle pins shoutd be thoroughly degreasedand cleaned of all carbon. This may be done with pumice powder and a scrubbing brush or if equipment is available, nitralloy pins should be cleaned in a hot alkaline electro-cleaner (one minute cathodic and one minute anodic). As the plating solution tends to corrode aluminum, it is recommended that any aluminum plugs or inserts be removed. The inserts are pinned in position, and it will be necessary to drill out the staking pin before attempting to remove the insert. This operation will damage the insert and will necessitatereplacement with a new insert after plating. Using Scotch paper masking tape, mask the bearing surface of the pin, i. e. the surface of the pin which is located between the inner faces of the master rod webs when the pin is installed. Plug all openings with suitable plugs so that only the outside surface comesin with the plating

Master

Rod Bearing

solution (see Fig. 524). Drill out rivets, or remove the threaded Allen plugs and press out the aluminum plugs. Replug the holes with temporary plugs. Rinse in cold water and, for nltralloy plns only, dip in a L\/o solution of hydrochloric acid at 160' F. (71" C.) for ten secondsand rinse in cold water again. The plating of chrome vanadium pins is accomplished by the use of sodium stannate acetate solution which is manufactured bv the DuPont Products Corporation. The composition of this solution is as follows: Bath Composition: Sodium Stannate Caustic Soda Sodium Acetate Hydrogen Peroxide (100 Vot.)

L2 oz. per gal. 1 oz. per gal. 2 oz. per gal. Xo oz.per gal.

Bath Temperature: 1 4 0 oF . - 1 6 0 " F . ( 6 0 ' c . - 7 1 ' C . ) Cunent: 6 Volts, D. C.-5 amps. per pin Plating Time: * 3 min. per .0001" of plate The plating of nitralloy knuckle pins is accomplished in Rochelle Salt copper cyanide bath as follows: Bath Composition: Metallic Copper 2-4 oz. per gal. Copper Cyanide 3-6 oz. per gal.

527


T H E S E C A P SA R E M A D E O F ALUMINUMAND SHOULD BE USEDAS A GUIDEFOR TAPING THE UNPLATEOPORTIONOF THE PIN AT THE BOUNDARY oF THE PLATED (NoN-snouuDERED)ENDS.

TAPE THIS

seeruore@

METHODS OF PLUGGINGAND TAPING TYPICAL KNUCKLE PINS BEFORE PLATING uore @

T H E P L U G SF l r r E D T o r H E E N D S A N D I N S E R T E DT H R U T H E I N T E R . S E C T I N GH O L E SO F T H E K N U C K L E PINS SHOULDBE MADE OF CLOTH M|CARDA,GRADE t+agt. tnts uetE R I A L I S A V A I L A B L EI N 4 E T . R O D S HAvTNGDtAs. oF t{' t" oR $" eruo ts MFG.BY THE WESTINGHOUSE E L E C T R T CC O . , T R A F F O R D ,P E N N .

Fig. 524 -

CAUTION: PLATING WHICH ADHERES TO AREAS OTHER THAN THOSE FOR WHICH ITS APPLICATION IS SPECIFIED MUST BE REMOVED BY BUFFING.

Methods of Plugging and Taping Knuckle Pins Before Plating

528


Fig. 525 _- Installing Piston Pin Bushing

Sodium Cyanide lTotal) Sodium Cyanide (Free) Rochelle SaIt Sodium Carbonate

4-7 oz. per 0.5-1.0oz. per 3-8 oz. per 2-8 oz. per

gal. gal. gal. gal.

140" F. (60" C.) Bath Temperature: 5 amps. per pin Current: Plating Time: x 3 min. per .0001" of plate *The maximum thickness of plate should not exceed.0001". After either type of plating the pins should be rinsed in cold water, unmasked, rinsed in hot water and dried. The pins should next be baked in accordance with the procedure outlined in the paragraph "Plating" (page 501), before being reinstalled in the master rod. Note-Hydrogen Peroxide should be added to the tin plating solution daily, or when necessary, in the amount of /s to % ounce per gallon of solution. 'lhis will tend to keep all of the tin in solution, and superior plating will be experienced. Rod Bushlngs-Should inspecArtleulatlng tion have revealed the necessity of replacing either or both of the articulating rod bushings, or should oversize knuckle pins have been fitted, making it imperative to replace knuckle pin bushings, the operation should be performed as follows: Mount the articulating rod under an arbor press and, using the Piston Pin Bushing or Knuckle Pin Bushittg Drift, press the bushing from the rod. When forcing a piston pin bushing from a rod, the staking pin, which securesthe bushing in the rod, will be sheared off. The

edges of the staking hole in the rod should be stoned to remove any burrs which may have been caused by the shearing of this pin. No pin is used to secure the knuckle pin bushing in position. New bushings may be installed with an arbor press, using the Piston Pin Bushing Drift (see Fig. 525), or the Knuckle Pin Bushing Drift and Plate. The knuckle pin drift shotild be pressed down against the shoulder of the articulating rod, which will cause the bushing to project approximately .003" on each end. Check the knuckle pin bushing end clearance in the master rod with a feeler gage (refer to the Table of Clearances). If necessary, face off the longer end with the Knuckle Pin Bushing Facing Cutter, used in conjunction with the Knuckle Pin Bushing Facing Holder, and the Knuckle Pin Bushing Facing Bushing. When installing a piston pin bushing, insure that the oil holes in the bushing are properly aligned with those in the rod. Each end of the bushing should protrude the same distance from the side of the rod. This should be checked with a scale. After installation of the bushing, transfer-drill the dowel pin hole in the bushing with a #t9 (.166") drill. The drill should extend %t" deep into the bushing. Place the dowel into the hole and expand with several sharp blows of a hammer, at the same time preventing the bushing from collapsing by placing the Piston Pin Bushing Expanding Mandrel inside the bushing, (seeFig. 526). If the inside of the bushing is not properly ed during this operation,

529


Fig. 526 -

Pinning the Piston Pin Bushing

the bushing will collapse slightly so that the dowel will be pushed out when the engine is run. The excessmaterial of the dowel pin should then be filed offflush with the contour of the rod. After installation in the rods, these bushings should be bored out to the desired size (see Fig. 527). For overhaul shop use, the Wadell Boring Fixture, manufactured by the Wadell Engineering Co., 354 Mulbemy St., Newark, N. J., has proven satisfactory for performing this operation. Special operating instructions are furnished with each fixture. When ordering, the purchaser should specify the engine type and model being overhauled, so that the proper instructions and special mandrels may be furnished.

\-,

\-

The following precautions should be taken when placing an articulating rod in the fixture. Before clamping the rod in place, a trial should be made to see that the rod fits up against the two aligning plates without rocking. If the rod rocks slightly on the aligning plates, the two edgesof the flanges are not parallel. It is permissible to use a fine file or stone on the edges of the flanges to make them the plates evenly and eliminate the rocking. If this precaution is not taken, the rod will spring slightly when it is clamped in the fixture. When the bushings are bored, and the rod released from the fixture, it will return to its original shape and the two bushings will not be parallel.

Subsequent to the installation and boring of new bushings, the alignment of the master and articulating rods should be checked on the Master Rod and Articulating Rod Aligning Fixture, "Inspection". as describedin Chapter IV, Plston Plns and Plugs-The piston pin plugs, which were removed to facilitate inspection, should be reinstalled in the piston pins if undamaged, or new plugs install-ed. R-efer to the Table of Clearancesfor the proper fit. It is recommended, if not already accomplished, that the latest type of Wasp Jr. piston pin be installed at overhaul. SeeChapter XVIII "Miscellaneous Conversions" for instructions for making this replacement. Wasp H1 and H1-G engines,starting with Nos. 6244 and 6223 respectively, incorporate a heavier section piston pin. If it is desired to incorporate this new type pin in engines manufactured previous to this change, the crankshaft requires rebalancing to offset the increased weight of the piston pins.. Directions for qgLi$-!his-change "Miscellaneous are given in Chapter XVIII Conversions". Flywelghts (Wasp and Hornet)-If for any reason, it is desired to remove a riveted-type flyweight, it should be accomplishedas follows: Drill a hole in the inner flyweight stem, using a drill of 14" less diameter then the stem, to

530


Fig. 527 -

Wadell Boring Fixture -

of the inner flyweight against relieve the pressure the outer. Chamfer the rivet end sufficiently to weaken the rolled over portion of the rivet. Separate the two halves of each flyweight by ins-erting a suitable drift in the drilled hole and oressing out with an arbor press. The riveted typ" should be replaced by the demountable type as follows:

Articulating

Rod

As replacement flyweights are all of the "removable type:' it is necessary to reoperate the flyweight liners when changing from the "riveted type" to the "removable type" on Wasp and Hornet engines. For complete information in regard to replacing flyweights on Wasp Jr., "Flyweights" Wasp and Hornet engines, refer to "Miscellaneous Conversions". Chapter XVIII,

BLOWER AND REAR SECTIONS Note-The jet in the hole to be bored should Irnpeller Shaft Bearlng Cage (Steel Cage) be examined to determine if it is sunk (Wasp Jr.)-The 'positionimpeller shaft bearing cage is far enough so that the cutter will not with a lug-headed loc\ing locked in touch it. If it is found to be protrudscrew. To remove the cage, bend back the lugs ing, a small hand grinder may be used on the locking screw and remove the screw. to grind the face of the jet enough to Heat the blower section (seePage 501) and then clear the boring tool. Blower the using out the cage, drift immediately Cage Disassembly Drift. After removal of the Before boring out the hole for the oversize caie, the hole in the blower section should be bearing cage, the oversize cage should be measmdasured for wear and out-of-round condition ured with a micrometer, to determine to what to ascertain if it should be reworked to accomdiameter this hole should be bored for the demodate an oversize cage. sired fit. A standard boring tool, using kerosene To rework the section to accommodate an oil as a cutting fluid, should be used with oversize cage, mount the crankcase blower seca lathe speedof between 150 and 200 R. P. M. tion with the front face against a suitable holding Scribe a line lengthwise in the new hole, interfixture in a lathe capable of swinging a section secting the centerline of the oil jet hole. Scribe of tlis size. With an indicator at the rear face a similar line on the O.D. of the new cage. Using and on the rear flange diameter, indicate the these lines as a guide, drift the cage into the blower section to run true within .001-", full blower section using the Blower Bearing Cage indicator reading. Thts ls funportant.

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES This operation will be faciliAssembly Drift. tated by heating the blower section. Make sure that the oil jet hole in the cage is lined up with the oil jet in the blower section. After installation of the cage, the locking screw hole should be drilled and tapped in the new cage. A #4 (.209") drill, which has been ground down so that only rA" of the flutes remain and which has been fitted with an extension, should be inserted in the tapped hole in the blower section and used to drill this hole. The smooth shank of the drill will act as a pilot for the drill in the tapped hole and will not damagethe threads, provided caution is exercised in using the drill. After drilling, tap out the hole with a rZ" -24 N.F. tap. Remove any excessmaterial or burrs from around the newly tapped hole. Insert the locking screw in the hole and bend over the locking tabs. If the screw projects through the cage, it should be removed and enough material removed from the end of the screw to provide a flush surface. knpeller Shaft Bearlng Cage Lock-In cases where the old type impeller bearing cagelocking screw is used on Wasp Jr. engines, it is recommended that the new special blower bearing cage locking screw with two lugs protruding from the head be used. To effect this change, the two staking slots in the blower section should be enlarged by means

531

of a small cape chisel having approximately s4nt'to r/16" radius on the point. 'fhis can be done quite readily without danger of chips getting into the parts or into the screw hole by performing the operation before removing the-old screw. The screw will project in the correct distance if it is screwed down until the outer ends of the two lugs are approximately flush with the casting. In some casesit may be found that the screw will bind a thread or two before this point is reached. The lugs can be bent into the slot making a very secure fastening. Irnpeller Shaft Bearlng Cage (Outboard Bearing) (Wasp and Hornet)-The impeller shaft bearing cage is secured in the blower section by nine screws. To remove the cage, these screws should be removed, the blower section heated (see Page 501) and the cage driven out with the Blower Bearing Cage Disassembly Drift. The hole should then be inspected for scoring and measuredfor out-of-round condition. Inspect the flange seating surface for general condition. Should it be desired to fit an oversize blower bearing cage, mount the front face of the blower section against a suitable holding fixture in a lathe Iarge enough to swing a piece of this size. With an indicator at the rear face and on the rear flange diameter, indicate the blower to run true within .001", full indicator reading. This ls irnportant. Note-The jet in the hole to be bored should be examined to determine if it is sunk far enough to clear the cutter. If there is not sufficient clearance, a small hand grinder may be used to grind the face of the jet enough so that the cutter will clear it. If any score marks or excessivenicks are found on the flange seating surface, this should be faced off, as the first operation, to assure proper seating of the cage. Before boring out the hole for the oversize bearing cage, the oversize cage should be measured with a micrometer to determine to what diameter the hole should be bored for the desired fit. A standard boring tool, using kerosene oil as a cutting compound, should be used with a lathe speed of between 150 and 200 R. P. M.

Fig. 528 -Removing

Oil Pressure Pipe from Rear Section

The new cage should be installed, after the blower section has been heated, with the Blower Bearing Cage Assembly Drift. When installing, take care to see that the screw holes in the cage are properly lined up with those in the blower section. Secure the cage in position with the nine locking screws. Interrnedlate Shaft Rear Bearlng LlnerShould it be necessary to replace this liner, it may be removed by drifting from the blower section with a suitable drift. Although this liner

532


Fig. 529 -

Reaming Magneto Shaft Bushing

is staked in place with a No. 24 pin, the pin will normally remain in the case when the liner is removed. Clean up the bore of the hole, if necessary, and drift in a new liner making sure that the notch in the edge of the liner coincides with the staking pin. maintain Starter Shaft Bearlng Liner-To the specified clearance of the starter shaft ball bearing in the crankcase blower section, a steel or bronze liner may be installed in the starter shaft bearing hole. This is a factory operation for which the blower section should be shipped back to United Airports Division, Rentschler Field, East Hartford, Conn. Bearlng Bolt Intermedlate Blower The blower intermediate bearing bolt used on later Wasp and Hornet engines has a land, \f" wide, in the center of its necked portion to dampen any vibration which might occur. Old type bolts, not having this land, may be utilized by wrapping a piece of %2" shim stock or wire around the center portion of the bolt so that it is fairly snug in the hole through the gear. The shim stock or wire may be secured with solder. Blower Bearlng Cover-Should the hole in the blower bearing cover be excessively worn necessitating replacement of the impeller shaft rear bearing spacer with a .010" or .020" oversize spacer, it may be accomplished as follows:

Assemble the cover to the blower section and, using the Blower Bearing Cover Reamer, ream out the cover to .978" for the .010" oversize spacer and to .988" for the .020" oversizespacer. The adapter used in conjunction with this reamer fits into the rear of the impeller shaft bearing cage and guides the adjustable blade. The blade is fed with a knurled knob and care should be taken in adjusting this knob to seethat too deep a cut is not taken. Oll Pressure Ptpe-Should the oil pressurepipe, which is located in the rear section, require replacement, it may be removed with the Oil Pressure Pipe Puller (see Fig. 528). If a new standard size pipe affords the proper fit, it may be installed in the rear section using the Oil Pressure Pipe Drift. This drift is designed to facilitate installing the pipe to its proper depth. In the event an oversize replacement pipe is required, the blower and rear sections should be reamed oversize. To accomplish this operation, the blower and rear sections should be temporarily assembled. The Oil Pressure Pipe Reamer should then be introduced into this fixture and the blower and rear sections line reamed. The total depth to which this reamer should be entered should not exceed416" on the Wasp Jr., Wasp, and Hornet E and E-G engines and 531" on the Hornet Ez-G and E3-G engines.

REPAIR AND ASSEMBLY OF MAJOR SIIB.ASSEMBLIES

Fig. 530 -

533

Facing Magneto Shaft Bushing

Magneto Shaf t Bushlngs-If it has beenfound n€cessaryto replace the magneto shaft bushings. the section in which the bushing is located should be heated (see Page 501) and the bushings drifted out with the Magneto Shaft Bushing Disassembly Drift. The removal of one magneto shaft bushing necessitates the removal of its mating bushing, as new bushings must be line reamed after installation. After removal of the bushings the hole should be checked for out-of-round condition and scorirg, and, if necessary, cleaned up with crocus cloth and oil or with the standard size Magneto Shaft Bushing HoIe Reamers. If difficully is experienced irr cleaning up or if it is desired to fit bushings oversize on the O.D., oversize reamers are available. In reaming these holes, it will be necessaryto temporarily assemblethe blower and the rear sections. The Magneto Shaft Bushing Hole Reamer should be inserted from the front side of the blower section after installation of its adapter on the magneto mounting pad to guide the reamer pilot. After the holes in the case have been reamed, the blower and rear sections should be reheated and the new bushings installed with the Magneto Shaft Bushing Assembly Drift. Assemble the

Magneto Shaft Bushing Reamer Guide Plate on the magneto mounting pad and iine ream the bushings, (see Fig. 529). After reaming. make sure that all chips are removed from the blower or rear sections, and check the rear flange clearance of the long magneto shaft bushings. This is accomplished wlth the Magneto Shaft Bushing End Clearance Gage which consists of a stepped "GO" and "NO GO" block and a bar. The bar should be inserted down through the vertical accessory drive shaft bushing. Then insert the stepped block through the oil pump or fuel pump recess and over the bar, and with the ((GO" and "NO GO" step, check the flange end clearance. Should the end clearance be insufficient, face the bushing with the Magneto Shaft Bushing Facing Tool (see Fig. 530). After the bushing is properly faced, temporarily assemble the magneto shaft and check the end clearance between the magneto shaft and the rear magneto shaft bushing. Starter Shaft Bushing-If necessaryto replace a starter shaft bushing, the rear section should be heated tsee Page 501) and the bushing drifted out with the Starter Shaft Bushing Disassembly Drift. After removal of the bushing, the hole should be checked for out-of-round condition and scoring and should be cleanedup with crocus

534


cloth and oil or the standard size Starter Shaft Hole Reamer. If difficulty is experienced in cleaning up or if it is desired to fit bushings oversize on the O.D., oversize reamers are available. After reaming the hole, reheat the case and install the new bushing with the Starter Shaft Before reaming the Bushing Assembly Drift. new bushing with the Starter Shaft Bushing Reamer, place the reamer guides in the starter mounting pad and in the starter shaft bearing boss and temporarily assemble the blower and the rear sections. Then ream the starter shaft bushing (seeFig. 531). Installatlon of a New Blower Sectlon on an is considered good pracOld Rear Section-It tice, when installing a new blower on an old rear, to replace the two magneto shaft and starter shaft bushings in the rear. If the oil pressure pipe is in good condition it need not be replaced; however, should it be oversize, the corresponding hole in the blower will have to be lined reamed with the rear section to accommodate the oversize. Remove the bushings from the rear section and clean up the bushing holes. If any of these bushings were previously installed oversize, the corresponding bushing hole in the blower will have to be reamed to the same oversize. When a new blower section is received from the factory the starter shaft bushing hole is the only

Fig. 531 -

Reaming Starter Shaft Bushing

one not reamed to standard size. Assemble and line up the blower and rear sections; then line ream this hole. Disassemble the two sections and install the new bushings, then reassemble. Align the tw_osgctions and line ream the bushings to size. Wash both sections thorougtrly to remove all chips. Note-The methods and tbols for line reaming bushings and cases,and removing andl inslalling bushings are described in the foregoing paragraphs for the separate items involved. If the oil pressure pipe in the old rear section is oversize, it will be necessary to ream out the oil pressure pipe hole in the new blower section to accommodate the oversize pipe. This may be satisfactorily done by removing the oil pressure pipe from the rear section; temporarily assemble the blower and rear section and ream out the oil pressure pipe hole in the blower section to the desired oversize using first an oversize Oil Pressure Pipe Hole Reamer with a pilot, then a plain oversize Oil Pressure Pipe Hole Reamer. Installlng a New Rear Sectlon on an Otd Blower Sectlon-When a new rear section is received from the factory the bushings and oil pipe will not be installed. In order to insure alignment of the blower and rear sections and permit line reaming the bushing holes in the rear section, it *ill be necessary to remove the magneto shaft bushings in the blower section as previously described. Assemble and align the two sections, and line ream the bushing holes in the rear section. The pressure pipe hole in the blower will act as a pilot for reaming the hole in the rear. If any oversize bushings have been installed previously, ream the holes in the rear section to the required oversize. Install the bushings in the blower and rear sections and line ream to size. Install the oil pressure pipe in the rear section. Wash both cases thoroughly to remove all chips. Note-The methods and tools for line reaming bushings and cases, and installing aud removing the bushings and pipe are described in the foregoing paragraphs for the separate items involved. Vertlcal Accessory Drlve Shaft Bushlng To remove this bushing, drive out the brass pin which stakes the bushing in place using a small steel drift. Then, with the Vertical Accessory Shaft Bushing Disassembly Drift, drive the bushlng fro;n tbe rear section, and clean up the bushing hole. If necessary,an expansion reamer may be used to enlarge the hole to accommodate an oversize bushing. Install the new bushing with the Drift and transfer-drill the staking pin hole with a No. 20 (.t6L" ) drill. Insert a steel bar into the bushing bore to prevent the bushing from collapsing and drive home the staking pin. The hole should then be reamed to the proper size

REPAIR AND ASSEIIIBLY OF MAJOR SUB.ASSEMBLIES with the Vertical Accessory Drive Shaft Reamer. This reamer is used in conjunction with a pilot which is mounted on the gun synchronizer mounting pad. Vacuum. Purnp l)rlve Llner-The Vacuum Pump Drive Liner Puller should be used for removing this part from the engine. With a suitable drift, drive the new liner into the hole until the flange of the liner seats on the shoulder in the hole, taking care to press the liner down evenly. Cocking will prevent proper seating. To determine if this liner has been properly bottomed, measure the distance from the flange of the liner to the face of the vacuum pump mounting pad with a depth gage. This depth should be .802" to .824". Intake Alr Ternperature Therrnorneter Interference-On Wasp Jr., Wasp, and Hornet E and E-G engines on which the intake air temperature is measured at the mixture duct of the rear section, the diameter of the hole in the upper vane of the mixture duct has been increased from Yta"to 2%2". In caseswhere this has not already b,eenaccomplished, this hole should be enlarged. Use a 2yurr counterbore with a %0" pilot, suppbrting the vane during this operation by means of a wooden block placed between it and the next lower vane. After boring, remove all sharp edges. Extreme care should be taken to remove all chips from the air intake age. inspection has revealed the necesOtl Pump-If sity for replacement of any one section of the oil pump housing, it will be necessary to replace the entire housing assembiy. Scratches and burrs in any section of the housing, not serious enough

535

to cause rejection of the casting, should be removed with a small triarlsul?r scraper, as emery should not be used on aluminum. Where insufficient clearance between t_hegeqrs and housing has caused the ggars to 4rb_ on the casting, this condition should be rectified by scraping enough "specifi6d material from the casting to Srlr" the clearance at this qoint, pro-viding lhe iubbing is not a result of some abnormal condition. Scratches and buns on the shafts should be removed by mounting the shaft in a polishing lathe and - pplislring -wit-h êlnety._ After polfuhing, check the fit of the shaft in the housing. If necessary to replace idler shaft use a solid steel drift that fits snugly into the hollow sear shaft to shear the pin from the inside of the sliaft. Drift out the part of the pin that extends through the gear on one side. Mount the gear and shaft in a drill press and drill out the remliniqg. put! of the qi4 to 1 deplh of,ap,proximately %a" inthe gear with a #31 (.120") drill-. The hol-e tfrougb_the gear and sha& is used as a guide for the driiligg operation. Remove the gear and clean up the pin holes. Pratt and Whltney Valve Lubrleator (Wasp Jr. B an$ B2)-In order-to prevent delivery oT an excessiveamount of oil to-the valve mec6anism, it is important that the clearance between the lubricator gear plunger and the housing be maintained within the specified limits. As o-versize plungersr are not available, excessive clearance will entail replacement of the housins. In caseswhere the angular end surface of thelubricator plunger shows signs of wear, it should be lapped smooth. Wlqere signs of flaking- are observed, the plunger should be renewed.

ASSEMBLY OF MAJOR SUB.ASSEMBLIES General-The assembly methods and procedures listed below, although playing an important part in efficient engine overhaul, will not be specifically mentioned in the "Detail Instructions" of this Assembly Section and the Final Assembly Chapter which follow. Although these items may seem of minor importance, the ultimate life and performance of the engine may be seriously affected if they are slighted through carelessnessor neglect. 1. During assembly operations, care should be taken to prevent dirt, dust, cotter pins, safety wire, nuts, washers, and any other parts from entering the engine. Suitable plugs and coverings to fit all openings should be improvised and used. 2. All bearing surfaces, anti-friction bearings, and movable parts should be thoroughly coated with oil.

3. All gaskets, packings and oil sealsshould be replaced at each overhaul. 4. A torque indicating wrench should be used when tightening the nuts which have recommended torques listed in the Appendix. 5. In all assembly operations refer to the Table of Clearances for the desired fit or clearance. 6. New safety wiring, tab washers, cotter pins, fiber nuts and palnuts should be installed where necessary. It is important that cotter pins and safety wire fit snugly in the holes for which they are intended. Always install the head or loop end of the cotter pin to fit in the castellation of the nut and not outside. The ends should be bent, one up and back over the stud or bolt end, and the other down flat against the hexagon flat ofthe nut.

536

REPAIR AND ASSEMBLY OF ITIAJOR SUB.ASSEMBLIES DETAIL INSTRUCTIONS FRONT (Nose) SECTION-WASP Tappets and Rollers-Prior to the assembly of tappets and rollers in the front section, the tappets should be coated liberally with oil. For Wasp Jr. B and 82 engines insert the spring into the tappet, slide the tappet into the guide, and secure it in position with the combination tappet and tappet guide locking screw. For the Wasp Jr. B3 engine, the rocker oil manifold should be placed inside the front section and secured to the tappet guide bosseswith the L8 combination locking screws. Then coat the tappets with oil and insert each in its respective guide. Draining type tappets should be installed in the following tappet guide locations: 1 In., 1 Ex., 21n.,28x.,3 Ex., 8 In., 9 In., and 9 Ex. After installation, the tappets should be depressed until roller pin hole clears the inner end of the tappet guide. Insert the roller in the tappet slot and slide the roller pin into position, making sure the ends of the roller pin are inside the tappet guide when the tappet is allowed to return to its normal position. FRONT (Nose) SECTION-WASP Propeller Otl Feed Plpe-Insert the propeller oil feed pipe through its hole in the front section and into the hole in the thrust bearing liner. Governor Drlve Gear (Wasp Hl only)-Coat the inside diameter of the governor drive gear bushing with oil and place the governor drive gear in position in its bushing. Secure in position with the locking ring. Intermedlate Governor Drlve Gear (Wasp El only)-Place the intermediate governor ilrive

JR.

Front Breather Assembly (If Provlded)Remove the cap flom the breather assembly dnd install the assembly -in the- nose section, turning it by means of a lever inserted between the screw bossesin the body of the breather. Install cap and secureit with the two screws. Propeller Regulator Valve (If Provtded) Prior to installation of the propeller regulator valve in the nose section on Wasp Jr. B ind 82 or the prgpeller oil stlnnly fttting on Wasp e_ngr.lgs Jr. 83 engines, the pipe leading from the resulator valve boss to the thrust bearing liner strbuld be installed. If a new valve and shaft is to be installed in !h9 pTopellgr regulator valve, it should be lapped into the valve seat with a fine lapping compound. -of After lapping make sure that all traces the compound are washed from the valve and seat. A +* pagkigs should be installed in the cover by twisting in the direction of the thread until it is bottomed. Slide the shaft through the cover from the bottom and install the packing nut in the cover. Install the lever on the outer end of the shaft and secureit in position with the taper pin. Fit the assembly in the case and secirre with three nuts. Hl AND EORNET E (Dlreet Drlve) gear il tbq intermediate-governor drive gear bushing. Assemble the pinion diive sear on the end of the shaft and lock in position i'ith the washer and nut. Assemble the inside the front section and secure with ihree retaining nuts. Instructions for adjusting the backlash between the intermediate governor drive gear and the governor drive gear are contained under the heading "Intermediate Governor Drive Gear Bushing" in the Repair Section of this Chapter.

FRONT sEcTIoN (Reductlon Gearlng and Houslng Assernbly) wasP El-G, HORNET E-G AND Ez-G Flxed Gear-Install the fixed gear in the front of the reduction gear housing and secure with the hold-down nuts and washers. For the Wasp H1-G engine, the propeller oil feed pipe should bb inserted in the oil pipe hole in the gear, prior to the assembly of the gear in the nose section. Secure in position with its hold-down clip after the fixed geaxis in place. When installing the fixed gear.on Hornet engines, see that the propeller oil feed pipe hole in the gear is properly aligned with the hole in the housing to permit subsequent installation of the propeller oil feed pipe.

lropel[e.r Otl Feed ltp" (Eornet Engtnes)Insert this pipe into the nose section and-into ihe oil pipe hole in the fixed sear; then secure it in pgsition by screwing the nose section oil age plug into the pipe hole. Ptrlton_C"gg (tVasp Hl-G)-The pinion shafts, pinio3 shaf-t holes, pinion races, and pinion gears are all numbered. When these parts are proferty assembled,--the numbers of the various mitin! parts should correspond. . Place the pjnion shafts in their proper holes in the rear half of the pinion cage ana phce the

537

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES cage under an arbor pJess. Press each pinion shaft into the cage (seeFig. 532). In performing this operation, see that the flats on the pinion shafts are lined up with those in the cage. Install the race on each pinion shaft and coat it with oil; then install each pinion gear over the race. Insure that aII gears have their identifying numbers facing to the rear. Place the front half of the cage on the rear half with the numbers on the pinion shaft holes and shafts corresponding. Assemble and tighten the pinion shaft nuts; then install the pinion shaft plugs in the shafts. Before installing pinion shaft plugs, run a tap (SAB-%6"-20 N. I'.) through the threads in the shaft to clear out the burrs and small plug slivers caused by the edges of the cotter pin holes when the plugs were removed. Line up the plugs with the cotter pin holes and secure with steel cotter pins. Secure the two halves of the cagewith 18 cage bolts and nuts, making sure that bolts are installed with heads toward the front. Plnlon Cage (Hornet E-G and E2-G)-When assembling the pinion cage, the numbers etched on the pinion shaft holes, pinion shafts and pinion gears should correspond on the various mating parts. Align the oil holes in the shafts and cage and press each shaft into its respective hole in the cagewith an arbor press. Install the race on each pinion shaft. Coat the races with oil and install each pinion on its respective race. Assemble the front half of the pinion cageto the rear half, correctly positioning the shaft holes to mate with their corresponding pinion shafts, and securewith L8 bolts and nuts. These bolts should be installed with the heads toward the front of the engine and secured with nuts and cotter pins. Ottly steel cotter pins should be used. Install the pinion -cage shaft washers and bolts in the pinion from the rear, assemble the lock washers on the ends of the bolts, and securewith retaining nuts.

portant to check thg ninch fit of the thrust bearing cover against the outer race of the thrust bearing as follows: Install cover in position on front section and tighten nuts only finger tight. Turn the front section over and measure at several points the distance from the shoulder of the liner where the rear face of the thrust bearing rests to the point on the cover directly forward. Next measure the width of the thrust bearing outer race and the tab spacer which rests against this race. The total of these two measurements should be from .004" to .008" greater than the distance from the cover to the rear shoulder of the Iiner. Adjustment may be made by either grinding the present spacer or installing a new thicker spacer. On engines having the steel ring riveted to the rear of the cover, the pinch fit may be reduced by removing the rivets which hold the steel ring to the cover and wet grinding the face of the ring which mates with the cover. The pinch fit may be increased by facing the flange of the cover sufficiently to afford the necessaryfit. Assembly of Propeller Shaft and Reductlon the propeller governor Gear Eouslng-Oil drive gear bushing (if provided) and insert the governor drive gear into position in its bushing. Securein place with the snap ring.

certain that the oil holes in Cautlon-Make the pinion shafts are aligned with the oil holes of the rear pinion cage. Propeller Shaft-On engineshaving the hydromatic propeller oil tube and plug assembly, insert the rear of the propeller oil tube in the plug in the propeller shaft. Install the gasket and over the front end of the tube, insuring that they seat evenly on the shoulder in the shaft. Assemble the gasket, shaft plug and plug nut. Tighten the nut and place the lock washer over the nut, securing it with three screws and washers. Checklng Plneh Ftt of Thrust Bearlng Cover-Before assembling the propeller shaft assembly in the reduction gear housing, it is im-

@ Fig. 532 -

Assembly of Pinion Shafts into Cage

538


Install the thrust bearing in position on the oroneller shaft with the Thrust Bearing Assembly St"d'rre. Place the propeller shaft in the Holding Adapter and with a Fi*trte fitted with fhe proper -assemble the oil transsuitable sleeve-type drift, fer ring carrier in position ol the shaft. Insure tttut tfre oil hole iri the carrier lines up with the oil hol" in the shaft. Install the oil transfer grooves of the carrier with the rinqs in the"PYre$s", facing the oil groove around sid6smarked the middle portion of the carrier.

Place the reduction gear housing on two wooden blocks, front up, on a bench and install shaft and thrust bearing in position the propeller -housing. Assemble the thrust bearing in the cover spacer (i-f provided), oil slinger, thrust nut and thiust bearihg cover and fasten temporarily with the thrust bearing cover nuts. Place the propeller shaft in the Holding Fixture and assembl-etlie pinion cage in positi-on with the Pinion Cage Push-er(seeFig. 533). Secure with the tab lock washer and lock nut.

FRONT SECTION (Reductlon Gearlng and Ilouslng Assernbly) HORNET the hydromatic proPropeller Shaft-Install as.previously plug-assembly ald tube ;;f"-r-;ii engines' E2 E and Hoinef i"t.tiU"a for the pinion- gears, pilion shafts Plnlon Cage-The -tnuft in the two halves of the holds ""a-pi"iott pi"i"" cage are numbered. It is important at lssemblv ihat the numbers on. adjacent parts when assembling.thg pinion shafts ."rr.rp""a the oil.holqsin the shafts must pinion cag9, in ttte i;;-ii;6d up wilh'those in the rear half of the "i"io" .ug; which is integral with the propgller |h;?l: tfi" pinion shafts should be pressed into

E3'G

the front half of the pinion cage using an arbor press. Alien the slots in the shaft with those in the cuge by turning them to the desired position with i ,4'' square shank after insertion in the cage. Place the front cageon a bench and install each race and each pinion geat,with its number to the rear, on its respective shaft. Then insert the propeller shaft, front-end down, t-hroggh the hole bf ttte cage. Raise the cage so that it meets the rear halfbf the pinion cage, turn pro!'eller shaft end for end, and- assemble the two halves of the cage. Assembly nlay be facilitqted by.tapplng th6 front cagelightly with a leather mallet. Install the froit and rbar pinion shaft washers and retaining bolts and tighlen nuts lightly. These bolts sn5ula be installed with their heads toward the rear of the engine in order to prevent.loss of oil pressure to the gearing. Install theêighteen through bolts that hold the two halves of the-ca-ge toget6er and tighten. The heads of these bolts sh6utd be installed so that they are toward the front of the engine. Tighten the pinion shaft bolts and securewith steel cotter pins. Assernbly of Reductlon Gear EouslngCheck the clamp fit of the thrust bearing cover as describedfor the Hornet E-G and E2-G. Oil the propeller governor drive ge?r bushing and then plac,i the governor-dri-vegear in position in its buihing. Seiure with the governor drive gear snap ring. on Install the oil transfer rings in their carrier "Press" the propeller shaft with the side marked i""i"g fhe oil groove- With the propeller shaft iront"end up, iistall the reduction gea!housing ir] Coaf the thrust bearing- with oil and nlace. âssemble in the housing, beveled side down' Drift it into place with-a suitable sleeve-type drift.

Fig.533-AssemblyofPinionCageonPropellerShaft

Assemble the thrust bearing spacer and cover and secure with the nuts and washers. Install lhe oil seal rings in their groove iq the thrust bearing nut. Alssemblethe nut on the propeller shaft finger tight.

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES BEARING

539

PLATE

Carn Reductlon Gear-Coat the inside diameter of the cam reduction gear bushing with oil and then place the gear in its bushing. The governor drive gear, (geared Hornets only) should then be placed in position on the front end of the cam reduction gear shaft and secured with the nut and washer. Propeller Governor Idler Gear (Ilornet E-G, idler gear bushing Ez-G, and E3-G)-Drift through front of anchor plate so that locking

grooves are in alignment with each other. Install idler gear lock plate and bolt, and stake head of bolt. Place idler gear on its bushing at the same time meshing it with the idler drive gear. Governor Otl Feed Plpe (Hornet E-G, Ez-G, the governor oil feed pipe and E8-G)-Install in place on the bearing plate and secure the pipe with its retaining bracket and clip.

MAIN CRANKCASE SECTION-WASP Carn Reductlon Gear-Prior to assembly of the cam reduction gear on the engine, the cam reduction gear locking nut should be tried in position on the gear to make sure that it seats oroperlv in the end of the shaft. Then oil the iatti reduction gear bushing and place the cam reduction gear in position in its bushing. Place the Cam Reduction Gear Holder over the front

JR.

of the gear and then assemble the cam reduction gear locking nut in place on the rear end of the shaft and tighten with the Cam Reduction Gear Nut Wrench. Check the clearance between the lock nut and the bushing and if insufficient, face the bushing enough to give the required clearance with the Cam Reduction Gear Bushing Facer.

MAIN CRANKCASE SECTION-WASP

Hl AND HORNET E SERIES

Front Maln Bearlng Outer Race and Rollers-Coat the front main bearing outer race and rollers with oil and insert into the front main bearing liner. On geared engines the front main bearing outer race and rollers should be secured in position with a retaining nut. This nut contains left hand threads and should be turned to the left with Front Main Bearing Retaining Nut Wrench. Adjustment for the proper clearance between this nut and the front main bearing outer race may be made by grinding the rear face of the nut.

The valve tappets usgd on early Wasp and H_ornet engines incorporated only two oil drain holes. When installing this type of valve tappet, care should be taken to align these holes with the grooves in the tappet guide. The valve tappets used on later Wasp and Hornet engines have four oil drain holes, thereby eliminating the possibility of installing the tappet so that oil will not drain through. Draining type tappets should be installed in the following tappet guide locations: 1 In., 1 Ex., 2In.,28x.,3 Ex., 8 In., 9 In. and 9 Ex.

Tappets and Rollers-Prior to assembly of the tappets and rollers in the front half of the main crinkcase section, the tappets and guides should be given a liberal coating of oil. Then insert each tappet in its guide and depressuntil the roller pin holes clear the end of the tappet guide. Insert the roller in the tappet slot and slide the roller pin into position, making sure that the ends of the roller pin are inside the tappet guide when the tappet is allowed to return to its normal position.

Carn and Otl Feed Bracket-Assemble the cam bearing on the cam shelf, making sure it is thoroughly seated by tapping lightly with a fiber drift. Coat the inside of cam with oil and assemblethe cam over the cam bearing. Assemble the cam oil transfer bracket and the cam retainer plates and securewith the necessarynuts. The cam end clearance should be checked by inserting a feeler gage between the cam retainer plate and the cam.

CYLINDERS Rocker Arm Bearlngs-Install the rocker arm bearings in the rocker arms with the Rocker Arm Bearing Assembly Drift and Base (see Fig. 534). The bearings of the early SKF type, having a single piece inner race for both sets of balls, should be installed in such a manner that the side thrust is not taken by that portion of the inner and outer race which contains the loading notches. The position of the loading notch is located by a stamped "O" on the inner and outer races. The marking on the outer race also indi-

cates the position of the oil hole and should be placed toward the adjusting screw end of the rocker when the bearing is installed in the rocker arm. The markings on the inner race should be placed toward the push rod end of the rocker when the rocker arm is installed in the cylinder. For rocker arm bearings having independent inner races for the two sets of ball bearings, the foregoing instructions are not necessary. The bearings are installed originally \{rith the grooved

540


, Fig. 534

Installing Rocker Arm Bearing

side outward. lt is permissible to reverse the positions of these bearings in the rocker arm and also to shift exhaust bearings over to the intake and vice versa, bearing in mind that the exhaust is the more heavily loaded. Rocker Arrns and Shafts (Wasp Jr.)-Place the rocker arms in their respective locations. Place the copper gasket on each rocker shaft with the smooth side of the gasket facing out. Insert the rocker shaft through the larger insert and rocker bearing. Install the rubber oil seal, steel washer, and oil fitting in place on the small end of the shaft and tighten. It is important to tighten the oil fitting prior to assembling the nut on the opposite end of the shaft in order to prevent rocker bearing side play. Place the rubber oil seal over the large end and install the oil seal lock nut, charnfer end in, and tighten in position. The coruect procedure for tightening rocker shaft nuts is to tighten snugly (approximately 35 inch-pounds on a torque indicating wrench) and then turn to the next cotter pin hole. A maximum torque of 135 inchpounds should not be exceeded. Later model engines incorporate valve rocker shafts having two 7(4" drameter cotter pin holes at right angles to each other, through the small end. Former shafts had only one such hole. The additional hole permits much closer adjustment when tightening the rocker shaft nuts to the desired torque.

F ig. 535 -

@

Installing Knuckle Pins in Master Rod

Shafts in use with but one cotter pin hole may be reoperated by drilling d %t" diameter hole at right angles to and intersecting the original hole. Roeker Arrns (Wasp and Hornet)-Place the rocker arms in their respective locations. Insert the rocker shafts through the large diameter holes and into position in the rocker bearings. Place the rubber oil seal, steel washer, and castellated nut in position on the small end of the rocker shaft and tighten this nut. Install the oil seal washer on the large end, then the copper gasket and the castellated oil seal locking nut and secure in place. Valves and Valve Sprlngs-Prior to assembling the valves in the cylinders, the valve guides and valve stems should be cleaned and oiled. Then install each valve in position. When installing the safety circlets be careful not to damage the lock grooves in the valve stems. Should the grooves become damaged, the locks will not seat properly and a valve failure may result. Then insert lower washers and springs in the rocker box housings and fit the upper washers over the springs. Place the cylinder over a piece of wood, having the same contour as the inside of the head, in order to hold the valves in place when the springs are compressedfor the installation of the split locks. Using the Valve Spring Depressor, depress the springs and install the split locks which secure the upper washers in place.

54L


FILE TO FIT

BEVEL TO CLEAR FILLET

SECTION OF MASTER ROD SHOWING KNUCKLE PINS AND LOCK. @ Fig. 536 -- Section of Master Rod Showing Knuckle Pins and Lock

Fig. 537 -

ARTICULATING

ROD ASSEMBLY

Assernbly of Artlculatlng Rods-The Knuckle Pin Press Fixture and Spacer should be used for installing knuckle pins in all single row engine models. A Bushing is used in conjunction with the fixture to accommodate Wasp and Hornet master rod bearings, the pilot of the fixture being the correct size for all Wasp Jr. bearings. On Wasp Jr. R, early Wasp Jr. F.2, Wasp, and Hornet engines, place the master rod, with the side marked "Front" facing down, on the spacer with the pilot of the fixture extending through the master rod bearing bore. Coat the knuckle pins and hoies with heavy oil such as Kendall No. 400 Gear Lubricant and insert an undersize dummy knuckle pin in a knuckle pin hole adjacent to the rtl" section of the master rod. Fasten the knuckle pin to be installed to the Knuckle Pin Setting Block and inserL it in the hole adjacent to thd dummy knuckle fiin, pushing it through the knuckle pin bushing of the proper articulating rod. The pilot on the Setting Block should then fit into the hole of the dummy knuckle pin. Locate the "L" head plunger over the Setting Block and force the knuckle pin into its hole by applying pressure to the handle of the fixture (seeFig. 535). Install the adjacent knuckle pin and articulating rod in a similar manner, inserting the pilot of the Setting Block in the first

Assembly of Crankshaft

knuckle pin instead of in the dummy knuckle pin for alignment. Repeat the above procedure to install the remaining knuckle pins and articulating rods. On late Wasp Jr. 82 and all Wasp Jr. 83 engines, the same procedure applies except that the alignment of the knuckle pins is achieved by the use of the Knuckle Pin Assembly Fixture. Set the Knuckle Pin Assembly Fixture (instead of the Spacer) on the Knuckle Pin Press Fixture so that the slotted front ends of the knuckle pins are resting in the projecting tongues on the aligning plungers in the Knuckle Pin Assembly Fixture. After all the knuckle pins have been properly aligned, press them in place in the master rod. On Wasp Jr. B, early Wasp Jr.B,2, Wasp, and Hornet engines the knuckle pins are held in position by locking plates on the rear of the master rod. These plates are held in position by a single screw. Locking plates are always furnished oversize and must be filed down so that they are a light drive fit between the flat surfaces of the adjacent knuckle pins (see Fig. 536). During the filing operations a small square should be used frequently to insure that the filed surface is square with the locking plate. When a new locking plate has been fitted, it should be etched with the numbers of the two pins that it holds

542

Fig. 538 -


Diagram Showing Direction of Thrust of Impeller Shaft and Intermediate Shaft Bearings - Steel Cage Type

Fig. 539 -

Diagram Showing Direction of Thrust of Impeller Shaft and Intermediate Shaft Bearings - Outboard Type

in place. On late Wasp Jr. 82 and B3 engines the knuckle pins are held in place by locking bars on the front ends of the knuckle pins.

These are held in place by two screws and safety wire for each pair of knuckle pins.

CRANKSEAFT Artleulattng Rod Assembly-Coat oil on the front and rear sections of the crankpin and apply a mixture of white lead and oil on the crankpin splines. Place the front portion of the crankshaft in the Crankshaft Holding Fixture fitted with the proper Adapter and mount the articulating rod assembly on the portion of the crankpin integral with the crankshaft fopward section, making sure that the side marked "FRONT" is placed towards the front of the crankshaft. Engage the ends of the crankshaft splines so that the two sections of the crankshaft are properly aligned. Using the Crankshaft Assembly Puller, assemblethe two sections together (seeFig. 537).

ASSEMBLY Flywelghts-To assemblethe demountable type flyweights use the Flyweight Assembly Puller. Before installing the expander, tighten the flyweight through-bolt with a torque of 1,300 inch pounds. Then screw the expander into place and tighten with a torque of 200 inch pounds. A 10-inch extension on the Allen PIug Wrench will facilitate this tightening. The end clearance of the assembled flyweight should be checked. If this end clearance is excessive, grind the rear face of the outer flyweight to obtain the necessaryclearance. Crankshaft Plug-,Screw the crankshaft plug into the tapped hole in rear side of crankshaft forward section, using the Crankshaft Plug Wrench. After tightening, stake into recess provided for this purpose. Front and. Rear Maln Bearlng Inner Races -Apply white lead or a generoun amount of oil to the main bearing seating surfaces on the crankshaft and on the I.D. of the bearing inner races. Install the races on the crankshaft using the Front Main Bearing Assembly Sleeve, and the Rear Main Bearing Assembly Pusher.

Thoroughly oil the crankshaft through bolt and screw it into the shaft, tightening it with the Crankshaft Bolt Wrench to the recommended torque specified in the Appendix. After tightening the bolt, secure it with a cotter pin fitted through the holes in the crankshaft rear cheek and the bolt head. It may be necessary to drill a new hole in the bolt to accommodate the cotter pin, but not more than three holes should be drilled in a bolt head.


Fig. 540 -

543

Assembly of Impeller with the Pusher

BLOWER SECTION (Steel Cage Type) WASP JR. Gear Assernbly-Assemble the Intermediate Iarge front ball bearing in position on the interme-diate gear shaft with the thrust side toward the front-(see FiS. 538). Place the intermediate gear and front bearing in the main cage and assemble the cage and intermediate gear in the blower, securing the cage with its retaining screws. Press the bushing into the rear ball bearing and assemblethe bearing,to the rear of the in[ermediate gear shaft, with its thrust side toward the rear. Screw the retaining nut on the rear end of the shaft and tighten finger tight. Floatlng Gear-Install the floating gear inner race ovei the front of the main cage and place the rear thrust plate in position, bevel side down over this race. Insert the roller pins in position in the gear using heavy oil to hold them in place. There are79 of theserollers used in each gear and, when installed, there should still be a space equal to slightly less than an additional roller pin. Assemble the floating gear over its inner race so it rests on the rear thrust plate. Place the front thrust plate over the floating gear, bevel side up. Then assemblethe lock plate,an_dnu!, tighten the nut, which has a left-hand thread, with the Floating Gear Nut Wrench. Check the end clearance between the floating gear and

rear thrust plate. Should the clearance be excessive, the use of new thrust plates will bring it to If the clearance within the desired limits. is insufficient the rear face of the floating gear may be ground off the necessary amount. Assemble the Blower Gear Holder on the floating gear and turn the blower section over. Tap th6 intermediate shaft rear bearing with a fiber drift to insure proper seating and then tighten the intermediate shaft nut, using the Intermediate Shaft Nut Wrench. Lock with a cotter pin. the front knpeller Shaft Assernbly-Install beaiing on the impeller shaft, with its thrust side in the position shown in Fig. 538. Install nut, tighten and secure with locking pin. Remove the floating gear lock nut and lock and place the shaft in the cage from the front; then install the two rear bearings with their thrust sides in the positions shown in Fig. 538. Assemble the closure over the rear bearing and determine the pinch fit of the blower bearing cover against the closure. This may be done by placing a straight edge on the rear surface of the closure and measuring the clearance between the straight edge and the surface of the blower section where the blower bearing cover rests. This clearance should be from .002" to .003".

544

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES Adjustment may be made by grinding the closure or installing a new, thicker closure. Temporarily assemble the blower bearing cover gasket, impeller shaft spacer and blower bearing cover. Install impeller and measure the clearance between it and the blower section. Adjustment may be made by grinding the impeller shaft spacer or replacing with a new spacer. After grinding, install the spacer on the shaft and check with a dial indicator to ascertain if it is running true within .001" full indicator reading. Try the spacer at various positions on the shaft until this condition is obfained. At this

time also check the end clearance of the impeller shaft and bearing assembly. An end pliy of .010" with new bearings is permissible. If excessive, new bearings should be selected. Install cover plate gasket and cover plate, securing with eight screws. Check the clearance between the spacer and the blower bearing cover plate with a feeler gage. Then install the impeller on the impeller shaft using the Impeller Pusher. Tighten nut using the Impellef Nut Wrench and lock ryith locking pin. Use Impeller Nut Locking Tool for the new type impeller nut and locking pin.

BLOWER SECTION (Outboard Type)-WASP Interrnediate Gear Assernbly-Place the blower section on the bench or engine stand with the rear side down. Install the intermediate blower drive shaft front bearing on the shaft with the thrust side in the position shown in Fig. 539 and place the intermediate gear in its recessin the blower section. Floatlng Gear-Place the floating gear inner race over the splines on the blower bearing cage so that its oil hole faces the right magneto shaft bushing when viewed from the rear. Measure the floating gear end clearance as follows:

AND HORNET

With the front and rear floating gear thrust washers assembled, flanges togethei and the large flat face outermost, measure the total thicknesswith a micrometer. Then measure the thickness of the face of each washer. Subtract the sum of the individual measurements from the previously obtained overall measurement. By subtracting lhe thickness of the flange on th-e front end of the floa_ting gear from this figure, the floating gear end clearance may be determined. If the end clearance is not within the desiredÎimits, it may be corrected by selecting a pair of thrust washers having the necessary overall measurement. Place one thrust washer, face down, over the bearing _rn4e{ race with the oil slot facing the starter shaft hole. Insert the 82 needle bearings into positiot in the _floating gear, using heavy oil to hold them in place. Assemble the-floating gea{ in position and place the remaining thrust washer over the floating gear, with the-oil slot matching the slot in the rear thrust washer. Place the floating gear lock nut spacer over the front thrust washer and install the locking nut temporarily. Assemble the intermediate blower gear rear bearing sqpport plale, tapping it into position over the bearing. Secure it with nine screws finger tight. Turn the blower section over. Press the intermediate shaft rear bearing bushing into the bearing with the flange of the bushing opposite the thrust side of the bearing (see Fig..539). Using a suitable drift, tap the intermediate shaft rear bearing into position on the shaft and into the liner in the blower section. Insert the intermediate shaft bolt throueh the shaft from the rear and assemble the washlr and nut on the end of the shaft. Turn the blower section over and tighten the nine screws securing the intermediate shaft front bearing plate.

Fig. 541 -

Checking Clearance Blower Case

Between

Impeller

and

Impeller Shaft-Assemble the oil baffie with the plain side towards the gear on the front of


BLOWERBEARINGCOVER

,/ /'

27297---" I - S C R E WN . O SAFETY W I R EN E C E S S A R Y .

h-ig 542 -

545

202 7-SCREWS TO BE S A F E T YW I R E D AT ASSEMBLY.

FILE OR GRTND ./. T H E H E A DO F , / THls scREgl---" , F L U S HW | T H T H | S / B E V E L E DS U R F A C E AT ASSEMBLY

Blower Bearing Cover Assembly Showing Location of Securing Screws

the impeller shaft. Then assemble the two front bearings with thrust sides as indicated in Figure 539. Secure the bearings with the nut and pin. Remove the floating gear lock nut and inslall the impeller shaft and bearing assembly. Place the floating gear lock nut spacer over the front bearing, aqsemblethe lock and floating gear lock nut. Tighten and secure in position-. With a feeler gage check the clearance between the lock nut and lock. The lock nut spacer may be ground on a surface grinder to obtain the desired-clearance. Again turn the blower section over. Assemble the oil baffie at the rear of the impeller shaft, bevel side down, and then install lhe impeller shaft rear bearing with the thrust in the position as shown in Fig. 539, using a suitable drift. Assemble the small oil baffie, the large oil baffie, and the laminated shim over the- rear bearing, thgn place the steel spacer in position on tbe impeller shaft. Place a small straight edge on the rear surface of the laminated sliim and determine the clearance between it and the surface of the blower section where the blower bearing cover rests. This clearance should be from .002" to .003". Adjustment may be made with the laminated shim. Temporarily assemble the blower bearing cover gasket and cover, and tighten with eighi screws. Assemble the impeller with the Impelier Pusher and measure the clearance between the

impeller and the blower section (seeFigs. 540 and 54L). Adjust to proper limits by removing the impeller and cover and grinding the impeller shaft rear spacer on a surface grinder. After grinding, install the spacer on the impeller shaft and check with a dial indicator to insure that it is running true within .001" full indicator reading. Try the spacer on at various positions on the shaft until this condition is obtained. At this time also check the end clearance of the impeller shaft and bearing assembly. An end play of .010" with new bearings is permissible. If excessive, new bearings should be selected. Install blower bearing cover gasket and cover, and secure with the eight screws. On Hornet Ez-G and E3-G models, seven of these eight screws are of one type, while the eighth may be identified by the absenceof the safety wire hbles. It is important that this latter screw be installed in the correct position as shown in Fig. 542, otherwise the diff may be damaged. If the'head of this screw projedts above ihe flat beveled surface of the cover assembly, it must be filed or ground flush to prevent interference with the diff. After installing all eight screws, secure the seven like screws with safety wire. Due to the location of the eighth, in relation to one of the diff vanes, this screw cannot back out when the diff is in position and ther,efore no provision for safety wiring has been made.

546

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES Check the clearance between the O.D. of the _sp?cerand the I.D. of the blower bearing cover hole (seeFig. 5a3). Install the impellerbn the impeller shaft. Tighten the impeller nut with the

Impeller Nut Wrench and lock with the locking pin. An Impeller Nut Locking Pin Flaring Tool is available for this pin.

REAR SECTION Generator l)rlve Assernbly (Wasp Jr., Wasp Hl, III-G, and Ifornet E. E-G)-Place tlie geaTin a softjawed vise and drift the bearing into position on the gegr shaft. Install the genelator drive gear nut. Using the Generator Diive Gear Nrt Wrench, tighten the nut taking care to align one of the holes in the nut witli the hole in the gear shaft. Secure the nut with a cotter pin. Assemble the unit in the bracket, and install the bearing retaining plate. Fasten the retaining plate with screws and safety wire. Drive the cork into the hole in the large.end of the generator drive geal. Where excessive generator drive spline wear has been encountered, it is recommended that old style cork plugs be replaced by those of a new type which ihcolporates a hollow tube for permitting oil or oil vipor to reach and lubricate the splines.

outer bearing. Place the lock washer and nut over the shaft and tighten the nut with the Generator Drive Gear Nut Wrench. Bend up the tab on the lock washer. Install the inner bearing retaining plate and fasten it with screws and safety wire. Drive the cork into the hole in the large end of the ge4elator drive gear. Where excessive generator drive spline wear has been encountered, it is recommended that a rZ,, hole be drilled through the ce-nter of the plug to permit glt gq oil vapor to reach and lubricate the rptitto. If this is to be .done,care should be taken fo prev-ept thp plW,from turning in the gear and biass shims should be used when clamping the gear to lvoi-d damage to the bearing sgat. After iiri[ing the hole,. remove all burrs and clean thorougHt before reinstalling in the engine.

Generator Drlve Assernbly (Ifornet E2- G and E8-G)-Drift the inner bearing into position on- the gear sbaft and assemble the geherator drive gear and bearing in the bracket. Place the spacer in position on the gear shaft and assemble

Oll^ Purnp _AsFerrrbly-I_nsert the drive gear qhaft through the cap of the oil pump. Fiithe key in the keyway on the drive shaft lnd assemble- the lF g" drlrr_" g.ear._ Place the idler gear and shaft assembly in- the .cap. Install large scavenge section over the drive and idler shafts and fit it to the cap. If the oil pu4p contain-s lhree sections, place tfe kgV itl_ tltg keyw_ay_ of the drive gear shaft; then install drive and idler ge,4rson tlieir respective shafts. Install the small scavenge sec-tion over the drive and idler shafts and fif it to the large scavenge section. If the oil pump contains only two stages the latter paragraph does not apply. Fit the key i! _the_keyway of the drive gear shaft and assemble the drive and idler sears on their respective shafts. Install the basetr pressure section of the pump over the drive- and idler shafts and fit it to the adjacent scavenge section. Fasten the pgmp together by inserting the two lgo,sefitting bolts and-tightening the nuts finger tigbt. Iqqert the two tight fitting bolts and tlien tighter_ra! four nuts securely. TLe gears should -is turn {r-eeJvby hand if the pump correctly assembled. Cautlon-Do not tighten the nuts excessively as the pump sections will be distorted and binil on the gearc.

!'ig. 543 -

Checking Clearance Between O.D. of Spacer and I.D. of Blower Bearing Cover Hols

Pratt and Whltney Valve Lubrlcator-Place t!,e drive gear in position in the bracket, and drive the shaft into position with a brass'drift. Place the two ball bearings in position in the bracket and insert the shift and spring assem-

547

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES bly. Fasten the cover plate, with its,gasket, in position with the propef nuts and washers. When installing the valve lubricator, it has been found that lhe marks on the sliding plate should be set at a point somewherebetween one, and one and three-quarters (L%) on the scale. However, this may not be a perrnanent settiqg' although'it may be used dui{ng- run-in of the engine] As a precaution, it is well to remove the rodker box covers after about ten (10) minutes of running and check to see if sufficient oil is beine furnfshed to the rocker mechanism of each cylinlder. If an ever-supply is being fqnishe-d, wnicn is hkely to cause sfiSht smoking from the exhaust, it tituy be overcome by setting the pointer at a lower position on the scale. If there is not enough oil found in the rocker boxes, that is, if the springs, washers, and rockers are not moist with oil, adjustment should be made toward the higher end of the scale. the inner Stde Vacuum Pump Drlve-Drift bearing into position on the vacuum pump drive-

sear shaft. Place the spacer over the gear Jnaft and assembleouter bearing over the spacer. Install and tighten the nut which secures the bearing on the shaft. Insure that the hole in the nuT ahgns with the lock pin hole in the shaft. If a new sf,aft is installed, a hole must be drilled in the shaft with a No. 40 (.098") drill, using the hole in the nut as a guide. Pin the nut to the shaft with a No. 8 cotter pin. Starter Shaft and Bearlng-Place the starter shaft on a clean wooden bench (gear end down). Assemble the bearing spacer, bevel side down, over the shoulder on the shaft. Push the bearing into position on the shaft. Otl Screen and Check Valve AssemblyInsert the oil scr@n and check valve assembly in the chamber of the rear section; then screw the oil screen chamber plug in place. sure that the rubber oil Cautlon-Make seal is correctly positioned between the valve assembly and the screen body.

548


TOOL LIST Wasp Jr. Tool Narne ADAPTER -

Tool No.

82

B3

-

ADAPTER

-

Crankshaft Holding Fixture. . .PWA-19L9-2

ADAPTDR -

Crankshaft Holding Fixture. . .PWA-1919-3

ADAPTER

-

Crankshaft and Propeller Shaft Holding Fixture ..PWA-1919-4

ADAPTER

-

Propeller Shaft Holding ture..

EI

Eornet

ET- G

Fix.PWA-1919-1

E

x x

x

x x

x

x

x

x

x

x

x

Magneto Reaming

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x x

x

x

x

x

Shaft

Bushing, ....PWA-820

Master Rod Bearing, Assembty..TAM-315

ARBOR -

Master Rod Bearing, Assembly. .TAM-267

ARBOR -

Master Rod Bearing, Assembly. .TAM-270

x

Aligning, Cam Reduction Gear and Intermediate Governor Drive Gear Bushing, Reaming... PWA-959

x

PWA-608-1

BAn

-

A[gning, Magneto Shaft Hole. . . . PWA-1981

BAR

-

Reamer, Bushing -

BUSEING

-

BUSEING

-

Cam

Reduction

x

x

x

x

x

PWA-970

Knuckle Pin Bushing Facing (Use with PWA-860 and PWA861) . . PWA-862-3

x

x

x

Knuckle Pin Press Fixture. . . . PWA-810-1

BUSEING

-

Knuckle Pin Press Fixture. . . . PWA-810-3

BUSEING

-

Starter Shaft, Reaming with PWA-60)

(Use . PWA-819

CLAMP

-

Tappet Guide, Reaming

. PWA-1369

CLAMP

-


. PWA-1370

CLAMP

-


. PWA-1371

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

...PWA-459

x

x

x

x

x

x

x

x

x

Rocker Bearing, Assembly and DisasPWA-614 semblv

x

x

x

x

x

x

x

x

x

Spring -

x

x

Knuckle Pin Bushing, Facing. . . PWA-861

AND BASE

x

x

Knuckle Pin Bushing Facing (Use with PWA-860 and PWA861). .PWA-862-1

DEPRDSSOR -Valve

x

x

Knuckle Pin Bushing Facing (Use with PWA-860 and PWA861) . . PWA-862-6

-

DRIFT

x

Gear

BUSHING

CUTTER -

x

x

Inlet Valve Seat, Removing

BUSEING

x

x

ARBOR -

-

x

Face Plate, Crankcase Holdins. . . .12950-T-11

ARBOR -

BAR

E . G E2- G E 3 - G

x

x

Crankshaft Holding Fixture. . .PWA-1919-1

ADAPTDR

ADAPTDR -

B

Wasp

549

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES TOOL LIST (Contlnued) Wasp Jr. Tool

Narne

Tool

No.

DRIFT

AND PLATE -

Knuckle Pin Bushing, Assembly . PWA-2SSL-4

DRIFT

AND PLATD -

Knuckle pin Bushing, Assembly. PWA-2551-3

DRIFT

AND PLATD -

DRIFT -

Wasp

B

82

B3

x

x

x

EI

x

EI.G

x

x

E

E . G D2. G 8 8 . G

x

Knuckle Pin Bushing, Assembly . . . . .PWA-2SSL-6

Blower Bearing Cage, Assembly pWA-64 and Disassembly

Ilornet

x

x

x

x

x

x

x

x

x

DRIFT -

Blower Bearing Cage,Assembly. . . pWA-lgZb

x

x

x

x

DRIFT

-

Blower Bearing Cage, Disassembly . .PwA-r976

x

x

x

x

DRIFT

-

Blower Bearing Cage, Disassembly PwA-2881

DRIFT -

Exhaust Valve Guide, Assembly. . pWA-94

DRIFT -

Exhaust Valve Guide, Assembly . pWA-Zgg

DRIFT -

Exhaust Valve Guide, Disassem-

PWA-279 DRIFT

-

x

x

x

x

x

-

Exhaust Valve Guide, Disassembly PwA-421

DRIFT

-

Inlet Valve Guide, Assembly

DRIFT

-

DRIFT

-

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Inlet Valve Guide, Disassembly . . .PWA-277

x

x

x

x

x

x

x

x

x

Knuckle bly .

x

x

x x

x x

x

x

x

PWA-95

Pin Bushing, DisassemPWA-1493

Knuckle Pin Bushing, Disassembly. . .PwA-2402

DRIFT

-

Knuckle Pin assembly

Bushing,

DRIFT

-

Magneto Shaft D i s a s s e m b l y . . ..

Long

Dis...... PWA-1749

Bushing, PWA-1?42

x

x

x

x

x

x

x

x

x

PWA-1?48

x

x

x

x

x

x

x

x

x

Magneto Shaft Long and Short Bushings, Assembly ..PWA-1?46

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Magneto Shaft Short Disassembly....

Bushing,

DRIFT

-

DRIFT

-

Oil Pressure Pipe, Assembly

DRIFT

-

Pinion Gear Bushing, Assembly and Disassembly PWA-1522

DRIFT

-

Piston Pin Bushing, Assembly and Disassembly.... PWA-1641

DRIFT

-

DRIFT -

x

x

Exhaust Valve Guide. Disassem-

DRIFT

DRIFT -

x

x

blv .

DRIFT -

x

PWA-261

Piston Pin Bushing, Assembly and Disassembly.... PWA-1494 Piston Pin Bushing, Assembly

. . PWA-2149

x x

x

x x

x x

550

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES TOOL

LIST

(Contlnued)

Wasp Jr. Tool

Narne

Tool

No.

DRIFT -

Piston Pin Bushing, Disassembly PWA-2092

DRIFT -

Propeller Governor Driven Bushing,Assembly

Gear . .PWA-1512

Propeller Governor Driven B u s h i n g ,D i s a s s e m b l y . . .

Gear ..PWA-1191

DRIFT

-

DRIFT DRIFT

-

DRIFT DRIFT

-

DRIFT DRIFT

-

DRIFT

-

DRIFT

-

DRIFT

-

DRIFT

-

DRIFT

-

B

82

Wasp

B3

E1

El.G

Ilornet E

x

D . G E2- G E3. G

x

x

x

x

x

x

x

x

x

Propeller Governor Driven Gear Bushing, Disassembly.. .. . .PWA-1961 Propeller Governor Bushing, Assembly

Drive

Gear . .PWA-1193

x

Propeller Governor Drive Bushing, Disassembly. . .

Gear . . .PWA-1194

x

Propeller Governor Drive Bushing, Disassembly...

Gear .PWA-2377

x

x

Propeller Governor Bushing, Assembly

Gear ...PWA-2378

x

x

Drive

Rocker Shaft Insert, Disassembly....

(Large)

Rocker Shaft Insert, Disassembly....

(Large)

Rocker Shaft fnsert, Disassembly....

(Smalt) PWA-1776

Rocker Shaft Assembly

fnsert,

(Small)


Insert,

(Large)

Insert,

(Large)


PWA-1466

x

x

x

PWA-1279

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

PWA-757

x

x

x

x

x

x

x

x

x

PWA-758

x

x

x x

x

x

x

x

x

PWA-759

DRIFT

-

Starter Shaft Bushing, Assembly. . PWA-762

x

x

x

x

x

x

x

x

x

DRIFT

-

Starter Shaft Bushing, Disassembly . PWA -r7 49

x

x

x

x

x

x

x

x

x

Vacuum Pump Drive Gear Bushing, Disassembly PWA-1460

x

x

x

x

x

x

Vacuum Pump Drive Gear Bushing, Assembly PWA-1648

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x

x

x

x

x

x

x

DRIFT DRIFT DRIFT -

Valve Tappet Guide Assembly. . . PWA-908

x

x

x

DRIFT -

Valve Tappet Guide Disassembly. PWA-2362

x

x

x

Vertical Accessory Drive Shaft Bushing, Assembly and Disassembly ....PWA-1800

x

x

x

x

x

x

DRIFT

-

DRILL

-

Valve Guide, Exhaust

PWA-822

DRILL

-


PWA-801

DRILL

-


PWA-643

Valve Guide, Intake

PWA-166

DRILL -

x

x

x

x

x

551

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES TOOL LIST (Contlnued) Wasp Jr. Tool

l-

B

82

B8

x

x

x

FACER -

Complete, Inlet Valve Seat Re(Use with surfacing PWA-6 Holder) . . .PWA-226-29

x

x

x

FACDR -

Complete, Inlet Valve Seat Re(Use with surfacing PWA-6 Holder) ...PWA-25L-24

E1

Hornet E . G 82. G E8-e

El- G

E

x

x

x

x

x

x

FACER -

FrontSpark Plug Bushing. . . . . . . . 1008-T-b

x

x

x

x

x

x

x

x

x

tr.ACER -

Rear Spark Plug Bushing. .

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Governor Drive (Use Bushing, PWA-861)

. 106g-T-g Gear with . . .PWA-1783

FIXTURE

-

Cam Reduction Gear Bushing, Reaming ....L62L-T-L7

FIXTURE

-

Cam Reduction and Intermediate Governor Drive Gear Bushings, Reaming... . .PWA-708

FIXTURE

-

FIXTURE

-

FIXTURE

-

FIXTURE

-

I'IXTURD

-

\-

\-

No.

Cam Reduction Gear Bushing. . . . PWA-62

FACINGI TOOL -

\-

Tool

FACER \-

\-

Narne

Wasp

x

x

x x

Cam Reduction Gear Bushing, Reaming ....PWA-214

x

Cam Reduction and Intermediate Governor Drive Gear Bushi n g s ,R e a m i n g . . . ..PWA-1341 Crankshaft and Shaft, Holding Governor Driven ing, Reaming...

Propeller ....TAM-206

x

x

x

Gear Bush..PWA-1039

-

FIXTURE

-

Knuckle Pin, Press

FIXTURD

-

x

Cam Reduction Gear Bushing, Reaming ....PWA-615

FIXTURE

FIXTURE

x

Knuckle Pin Assembly withPWA-296\

x

x

x

x

(Use ...PWA-2557

x

x

x

x

x

x

x

x

x

x

x

Master Rod and Articulating Rod, Aligning. ....PWA-1781

x

x

x

x

x

x

x

x

x

Rocker Arm Ball End Socket Disassembly.... PWA-1352

x

x

x

x

x

x

x

x

x

x

x

x

x

PWA-296

GAGD -

Exhaust Valve Guide, Plug.

1516-T-10

GIAGE -


.45639-T-2

GAGTD-

Exhaust Valve Guide, PIug.

. 17101-T-1

GAGE -


GAGD -

Inlet Valve Guide, PIug.

GAGD -

Magneto Shaft Clearance

Bushing,

GAGE -

Maximum Bushing

Magneto

Wear,

x

x

x

x

x

x

x

x

x

x

x

x

x

x

End . .17216-T-I

x

x

x

x

x

x

x

x

x

Shaft ...PWA-1451

x

x

x

x

x

x

x

x

x

23408-T-1 . . .1516-T-11

552

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES TOOL LIST (Conttnued) Eornet TooI Narrre GAGE -

Maximum Bushing

Wear.

Tool No. Starter

Shaft . PWA-145I-28

EOLDDR -

Blower Gear (Steet Cage)

EOLDDR -

Blower Gear (Outboard Bearirrg).. ..pwA_609

-

Cam Reduction Gear (Use with PWA-7) PWA_248

EOLDDR -

Knuckle Pin Bushing Facing. . . PWA-8G0

EOLDDR -

Valve Seat, Inlet.

. .3b80-T-2

EOLDER -

Valve Seat, Inlet.

. .L2794-T-B

Valve Seat, Inlet.

.8692-T-8

EOLDER

EOLDER MANDRDL

-

. PWA-398

Expanding, Piston Pin Bushing, Pinning... . .PWA-L777

-

Starter Shaft Bushing, Reaming. . PWA-815

PLATE -

Starter Shaft Bushing, Reaming. . PWA-812

PILOT

PLATD

-TappetGuide,Aligning

PLATD

-TappetGuide,Aligning

PLIERS -

. . .PWA-82? . . .PWA-1302

Piston Ring.

. .PWA-1791

PLUG

-Tappet

Guide, Aligning

...PWA-828-1

PLUG

-Tappet

Guide, Aligning

...PWA-828-3

PLUG

-Tappet

Guide,Aligning

...PWA-828-2

PLUG

-

Tappet Guide, Aligning

. . .2733-T-2

PULLER AND PUSEEB -

Cam Reduction Gear Bushing, Assembly and Disassembly. . . PWA-220

PULLER AND PUSEER -

Cam Reduction Gear Bushing, Assembly and Disassembly. . . PWA-624

PULLER AND PUSEER -

Impeller. . .. . . .PWA-1306

PULLER -Crankshaft,Assembly

. . . .PWA-1065

PULLER -Crankshaft,

Assembly

. . .PWA-604

PULLDR -Crankshaft,

Assembly

.. . .PWA-510

PULLDR -

Exhaust Port Liner

PULLER-Flyweight,

Assembly

. PWA-1775 ...PWA-1067

PULLER -

Oil Pressure Pipe.

PULLDR -

Propeller Governor Driven Gear Bushing, Assembly .PWA-1190

PULLER

-

Push Rod Tube Packing Gland

. . PWA-760

PWA-849

DD.J

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES TOOL LIST tContlnued) Wasp Jr. Tool Narne

Tool No.

B

PULLDR -

Vacuum Pump Drive Liner

pWA-1881

x

PULLER -

ValveTappet BallSocket. . . . . . .pWA-1081

x

PULLER -

Valve Tappet Guide

82

W asp B3

. .pWA-1068

PUSEDR -

Front Main Bearing, Assembly pWA-66b

PUSEDR -

Impeller, Assembly....

. .PWA-1882

El-G

x x

x

pWA-254

PUSEER -Flyweight,Disassembly

E1

Ilornet E

E - G E2. G E 3 . G

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x PUSEER-Pinion

Cage

..PWA-4G6

PUSEDR -

Propeller Shaft Rear Bearing

PUSEER -

Propeller Shaft ll,ear Bearing.. . . 14088-T-19

PUSEER -

Push Rod Tube Packing Gland. PWA-491

x

x

x

PUSEER -

Rear Main Bearing, Assembly. . PWA-208

x

x

x

PUSEDR -

Rear Main Bearing, Assembly

PUSEER -

Rear Main Bearing, Assembly. . PWA-GG6

PUSEER -SparkPlugRushing...

x

x

x

x

x

x

x

x

x

x

x

x

x

x

PWA-859

PWA-O19

x

x

x

x

. . .3510-T-16

x

x

x

x

x

x

x

x

x

. . PWA-818

x

x

x

x

x

x

x

x

x

Cam Reduction Gear Bushing, Rough PWA-210

x

x

x

x

x

x

x

x

x

Cam Reduction Gear Bushing, Finish . . PWA-711

x

x

x

x

x

x

x

x

x

REAMER -

Exhaust Valve Guide

x

x

x

RDAMDR -

Exhaust Valve Guide

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

REAMER

-

RDAMDR -

BDAMER

-

Blower Bearing Cover

RDAMER -Exhaust REAMER RDAMER REAMDR -

REAMER

REAMER

-

-

REAMER REAMER

REAMER

-

-

Valve Guide

Expansion, Guide Hole.

Exhaust


Exhaust


Exhaust

PWA-299 .

PWA-806 ...PWA-1050

Valve PWA-302

x

x

x

Valve

x

PWA-303 Valve .PWA-417

Expansion, Inlet Valve Guide Hole. . PWA-301

x

x

x

Governor Driven Gear Bushing (Use with PWA-1039) PWA-1040 Inlet Valve Guide

x

. PWA-298

x x

x

x

x

x

Intermediate Governor Drive GearBushing,Rough.... PWA-710

x

Intermediate Governor Gear Bushing, Finish

x

f)rive . PWA-711

x

x

554

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES T OOL

LIS T

(C ontl nued)

Wasp

Iilasp Jr. Tool Narne REAMDR -

REAMER

-

REAMER

-

REAMER -

T o o l N o.

B

B2

B3

E1

H T -G

Ilornet E

E . G E2-G 83. G

Intermediate Governor Drive Gear Bushing Hole, Rough + 10 (Use with PWA-1341) . PWA-1339

x

x

x

Intermediate Governor Drive Gear Bushing Hole, Finish * 10 (Usewith PWA-1341) . ..PWA-1940

x

x

x

Intermediate Governor Drive Gear Bushing Hole, Rough + 20 (Usewith PWA-1341) PWA-1349

x

x

x

Intermediate Governor Drive Gear Bushing Hole, Finish * 20 (Use with PWA-1341) . PWA-1350

x

x

x

REAMER

-

Magneto Shaft Bushing Hole. . PWA-61

x

x

x

x

x

x

x

x

x

REAMER

-

Magneto Shaft Bushing

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Oil Pressure Pipe Hole Reaming.. ...PWA-2071

x

x

x

x

x

x

x

x

x

Oversize Oil Pressure Pipe, HoIe to Blower . . PWA-171 + 10

x

x

x

x

x

x

x

x

x

Oversize Oil Pressure Pipe, Hole to Blower PWA-171 + 20

x

x

x

x

x

x

x

x

x

Oversize Oil Pressure Hole Reaming. .

Pipe PWA-2071+10

x

x

x

x

x

x

x

x

x

Oversize Oil Pressure Pipe Hole Reaming. . . PWA-2071 +20

x

x

x

x

x

x

x

x

x

Starter Shaft Bushing (Use in conjunction with PWA-815, PWA-917, PWA-919, PWA820) PWA-58

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

RDAMER REAMER

-

REAMER

-

REAMDR RDAMER RDAMER REAMER

-

Oil Pressure Pipe, Blower

. PWA-57

Hole

to PWA-171

REAMER

-

Starter Shaft Bushing Hole. . . . PWA-60

x

x

x

REAMER

-

Stepped, Rocker Shaft Insert

x

x

x

. PWA-1682

REAMDR -

Stepped, Rocker Shaft Insert. . . 13824-T-3

REAMER -

Valve Tappet Guide, Firsr Cut. PWA-1347

x

x

x

-

Valve I'appet Guide, Spiral . . . PWA-1348

x

x

x

RDAMER -

Valve Tappet Guide, First Cut. PWA-1368

x

x

x

x

x

x

REAMDR -

Valve Tappet Guide, Second Cut PWA-1346

x

x

x

x

x

x

x

x

x

x

x

x

REAMER

REAMER AND FIXTUBD

REMOVER -

-

Vertical Accessory Drive Shaft Bushing.....1171-T-1

Intake Valve Seat (Use with PWA-608-1) . . PWA-329

x

x

x

x

x

x

555

REPAIR AND ASSEMBLY OF MAJOR SUB-ASSEMBLIES TOOL

LIST

(Contlnued) W asp

Wasp Jr. Tool N o.

Tool Narne RDMOVER -

Intake Valve Seat (Use with PWA-322 PWA-608-1)

REMOVDR -

Intake Valve Seat (Use with PWA-323 PWA-608-1)

RDMOVER -SparkPlugBushing RING -

Master, for Setting Block and In....3472-T-3 dicator

RING -

B3

x

x

x

x

x

x

E1

El- G

x

x

x

x

x

x


SDTTING BLOCK -

Knuckle Pin

. .PWA-1769

SETTING BLOCK -Knuckle

Pin

...PWA-715

SDTTING BLOCK -Knuckle

Pin

...PWA-713

SLDEVE -

Front Main and Thrust Bearing, PWA-79 Assembly

SLDDVE -

Front Main Bearing, Assembly . .PWA-622

SLEEVE -

Front Main Bearing, Assembly. . PWA-701

SLEEVD -

Thrust Bearing Assembly

. . PWA-156

SLEEVD -

Thrust Bearing Assembly

. . PWA-536

SPACDR -

Knuckle Pin (For use with PWAPWA-2093 296).

SPACER SPACER TAP -

B2


RING -

x

x

Plug Bushing...

. .PWA-1526

TOOL-CrankpinLapping....

.PWA-981-1

TOOL-CrankpinLapping....

.PWA-981-3

E

E - G 82. G E 3 . G

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x x

x

x

x

x

x x

x

Knuckle Pin (For use with PWA. PWA-2530 296) .

Spark Plug Bushing Hole in Cylinder. PWA-334

TOOL -

x

Knuckle Pin (For use with PWA...PWA-2252 296).

TAP -Spark

\-

. . . .PWA-1262

B

Hornet

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x x

x

x

x

Crankpin Lapping (Use with PWAPWA-981-6 980).

TOOL -

Impeller Nut Locking Pin. . : . . .PWA-1558

x

x

x

x

x

x

x

x

x

TOOL -

Magneto Shaft Bushing, Facing. . . . PWA-55

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x

x

x

TOOL -Valve

L a p p i n g ,E x h a u s t

....PWA-ll

TOOL -Valve

L a p p i n g ,E x h a u s t

....PWA-117

TOOL -

Valve Lapping, Inlet.

WEDGE -Expandittg...

PWA-10

x

x

x

x

x

x

x

x

x

PWA-991

x

x

x

x

x

x

x

x

x

WRENCE -

C a m R e d u c t i o nG e a r N u t . . . . . P W A - 7

x

x

x

WRENCE -

Crankshaft BoIt (Ir4" hex.) . . . PWA-1914

x

x

x

oDo

REPAIR AND ASSEMBLY OF MAJOR SUB.ASSEMBLIES TOOL LIST (Conttnued) Wasp Jr. Tool Narne

Tool No.

WRENCH -

Crankshaft Bolt

. PWA-603

WRDNCE -

Crankshaft Bolt

PWA-106

WRENCH -

Crankshaft Plug

WRENCE -

Floating Gear Retaining Nut. . PWA-345

WRENCE -

Front Main Bearing Retaining PWA-648 Nut. .

WRDNCH -

. . PWA-7

B

82

Wasp B3

ET

HT- G

x

x

Hornet E

E . G D2. G 8 3 . G

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Front Main Bearing Retaining PWA-659 Nut

WRENCE -

Generator Drive Gear Nut

PWA-174

x

x

x

x

x

x

x

x

x

WRENCE -

Impeller Nut

PWA-1269

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

WRENCE -

Intermediate Blower Gear Nut . PWA-347 . (Steel Cage)

WRDNCE -

Pinion Cage Lock Nut. .

PWA-502

WRDNCE -

Pinion Cage Lock Nut. .

PWA-660

WRDNCE -

Reduction Drive Gear Nut

WRENCE -

Reduction Drive Gear Nut. .

WRENCE -

Spring BlowerDrive Bolt. . . . . .PWA-1195

x

x

. . PWA-487 PWA-660

x

x

x

x

x

x

601

CHAPTER VI

FINAL ASSEMBLY GENERAL INFORMATION After the sub-assembliesand accessorieshave been cleaned, inspected, repaired and reassembled as described in the previous chapters, they should be forwarded to the final assembly line for assembly. The instructions in this chapter are written with the assumption that new gaskets and rubber seals will be installed where they are required,

replacing those which were removed at disassembly; all mating gears, shafts, bearings and fitting surfaces on oil pipes will be adequately oiled prior to installation; all safety wiring, palnuts and cotter pins will be installed where necessary, following the final assembly of each part; and all the necessary fits and clearances will be checked for the required limits contained in the Service Table of Clearances.

FINAL ASSEMBLY the swivel Blower and Rear Sectlons-Turn top of the Engine Overhaul stand to a horizontal position and attach the blower section to the top of the Mountilg Plate with the impeller facine downward. Then secure blower section to stand-with at least five mounting bolts. Turn the blower section so that impeller is facing upward. Fit gasket over studs and on the parting face of blower section, where it s the rear section. Then assemble rear section to blower and secure with the necessary nuts and washers. It may prove necessary to lightly tap the rear section irittr a fiber drift at the magneto and starter drive shaft locations. Be sure case or bushings are not distorted or damaged. rear section should be pushed Cautlon-The evenly on the blower to prevent damaging the oil pressure pipe and horizontal drive shaft bushings. Turn the accessory section with the stand so that the rear section lies in its normal flying position and proceed with the installation of the following: each Vertlcal Accessory I)rlve Shaft-Insert shaft through its respective bushing in the rear section. Fit ball bearing (and gun control gear, if provided) over upper end of each vertical drive shaft and secure with nut. Each nut should be tightened only finger tight on its respective shaft at this time. tachometer shaft Tachorneter Shafts-Insert into its respective hole in the rear section and ensase its gear teeth with those on vertical acdeslory diive shaft. Place gasket against tachometer coupling mounting pad on rear section. Then secure tachometer shaft in position by fastening tachometer drive coupling to rear section with two fillister head screws. The

tachometer shaft or shafts may be installed on left and/or right side of the rear section, depending upon whether one or two shafts are used. In this connection, it is important to install each tachometer drive coupling on its particular side of the engine. Each coupling has a spiral oil groove in its bore to provide a return for the oil which leaks past the bushing. If installed on the wrong side, this groove would assist oil leakage rather than prevent it. On engines shipped from the factory the tachometer drive pads on "1" for the right the rear section are marked No. "2" for the left side (viewed fror^r side, and No. the rear). The couplings are similarly marked and the numbers on the rear section and coupling should correspond when properly positioned. starter shaft Starter Jaw and Shaft-Insert through its bushing so that the splined end of the shaft protrudes into the rear section. If necessary, tap shaft with hammer and fiber drift and drive ball bearing completely into recess of blower section. Fit starter jaw and washer over end of starter shaft in the order mentioned; then screw nut on end of shaft and tighten. Starter Shaft End Clearance-After installation of the starter shaft, the clearance between the starter jaw and the face of the starter shaft bushing should be checked. As all engines are carefully checked before leaving the factory for the desired starter shaft end clearance, it should never be necessary to increase this clearance except when new parts are installed, or unless a gasket of abnormal thickness is used between the blower and rear section. However, if less than the minimum clearance is found with the original parts installed, check to see that the bushing has not worked backwards in the rear section. Should the end clearance be excessive, the flange of the starter shaft bushing should be

602

FINAL

Fie. - 601 -

ASSEMBLY

Checking Starter Shaft Bushing with Flush Pin Gage

checked for wear using the Flush Pin Gage (see Fie. 601) to determine if its thickness is within th6 desired limiting dimensions. This is very important as the backlash between the generator drive gear and the starter jaw gear is controlled bv the end clearance of the starter shaft. If the birshing flange is worn excessively, installation of a new bushing should, in most cases,correct the See Chapter V for instructions on difficulty. installing a new bushing. If, after a new bushing is installed the de.sired clearance cannot be obtained, further adjustment may be made by changrng the thickness of the rpu-c"r located iir fronfof-the starter shaft ball bbaring. This may be done by installing a thicker spacer or by grinding down the present one, d-ependingwhether it is necessary to increase or decrease the clearance. Starter or Starter Cover-Place gasket against starter mounting pad on rear section; then fasten starter or starter cover to rear section with the necessary nuts and washers. the generGenerator Drlve Assembly-Install ator drive assembly in position on the rear section and insure that the gear teeth of the generator drive gear and the qtarter -ju* gear are properly engaged. A rubber oil seal is required between the flange of the generator beiring housing and the mounting pad of the rear section. Check the backlash between the

Fig. 602 -

Checking Backlash between Generator Drive Gear and Starter Jaw Gear

generator drive gear and starter jaw g€r, usi4g a dial indicator. The dial indicator should be mounted on a stud of the starter drive pad with the plunger resting on a generator drive gear tooth (see Fig. 602). This backlash should be checked first with the starter jaw pushed as far forward as possible and then again with it pushed as far to the rear as possible. When in the forward position the backlash should not be less than the minimum specified while in the rear position it should not exceed the replacement limit. If this backlash exceeds the replacement limit, the teeth on the generator drive pinion and starter jaw gear should be carefully examined for pitting and wear. If the excessivebacklash cannot beadjusted through the starter shaft and bushing, it is prmissible to machine the lower face on the flange of the generator bearing housing, until the proper backlash is obtained. Should the backlash be found insufficient, it should be increased to the proper value by installing one or more steel shims between the flange of the generator bearing housing and the mounting pad on the rear section. This should be done only when no further adjustment can be made through the starter shaft assembly. Place the gasket and cover over top ofgenerator drive assembly and secure with four nuts and washers.

FINAL ASSEMBLY Magneto Drlve Shafts-Insert each magneto drive shaft (from forward side of blower section) into its respective bushings in blower and rear sections. Before the shaft is pushed completely through its bushings, the pump and gun control gear should be held against the face of rear magneto drive shaft bushing. Then the shaft may be pushed through the gear and into position. Drive key into keyways of the pump and gun control drive gear and magneto drive shaft, using a hammer and brass drift if necessary. Insert magneto drive shaft oil shield through hole in magneto drive cover mounting pad and into position. Fasten magneto drive cover and gasket to its respective mounting pad on rear section, using four fillister head screws. Be sure that a gasket is fitted between each cover. The leather oil seal incorporated on each magneto drive cover should be in good condition, or the cover should be replaced. Fit each magneto coupling flange over end of magneto drive shaft, lining up the keyway with the key which is already in place in the drive shaft, and secure in position with screw. Lock the magneto drive shafts and tighten screws which fasten magneto coupling flange to each shaft. gasket over mounting flange on OII Pump-Fit oil pump housing. Insert body of oil pump into its bore in the lower right hand side of the rear section and engage teeth of oil pump drive gear with those of the bevel pump and gun control gear. The oil pump assembly should then be fastened to the rear section with the necessary nuts and washers.

603

and in accordance with the same procedure as that specffied for the instaliation of the fuel pump drive. Conhect lubricator pump oil supply pipe to oil _inlet _and pressure holes in lubricatoi pump body and rear section respectively. Gun Drlve or Accessory Drlve Covers-Place gasket on each vertical drive pad on top of rear section, then secure each cover to its respective pad with four nuts and washers. If gorr synchronizers or other accessoriesare to beinstafed in lieu of gun drive covers, make sure that the proper backlash is obtained between the two mating gears. Vacuum Pump_ Drlve-Insert vacuum pump drive shaft and bearing assembly into b6re of liner on left side of rear section. Be sure teeth of vacuum pump drive gear and fuel pump drive gear are properly meshed. Place gasket over inner face of mounting flange on vacuum pump drive housing, and then push housing into position in the rear section. Install spacer and oil seal in vacuum pump drive housing. Check backlash between vacuum pump drive gear and pump and fuel pump drive gear (see Fig. 603). I_nstall gasket and vacuum pump (or cover) over flange of vacuum pump drive housing and secure with nuts and washers.

Check the backlash between the oil pump drive gear and the pump and gun control gear. Adjustment of the backlash between these gearsr may be made by facing the magneto drive shaft bushing in the rear section, or by installing a new bushing, but it must be ed that the backlash of the vertical accessory drive shaft will also be affected. See instructions on this subject in Chapter V. Fuel Pump l)rlve and Fuel Pump-Insert fuel pump drive gear shaft through hole in boss of fuel pump drive gear bracket, Install fuel pump drive gear bracket and gasket on lower left hand side of rear section, and engage teeth of fuel pump drive gear with those of bevel pump and gun control gear. Be sure that the proper backlash is obtained. As described for the oil pump, adjustment may be made by facing the, magneto drive shaft bushing flange. Place gasket over mounting flange of fuel -drive pump and engage pump shaft with fuel pump geqr shqft. _Fastenpump into place on fuel pump drive bracket with the necessary nuts anii washers. Pratt and Whttney Lubrlcator Pump (Wasp Jr. B and B2)-As this unit is integral with the fuel pump drive, it is installed at the same time

Fig. 603 -

Checking Backlash between Vacuum Pump Drive Gear and Fuel Pump Drive Gear

604

FINAL ASSEMBLY

c d rr ^ Ao. oo o,a

rff ore.

rfi brn)

l'5toos

il

INSTALL ONLY BETWEEN REAR S E CT I O N A N D V AC U U MP U MP D R IVE HOUSING.

Fig. 603,4.-

INSTALL ONLY BETWEEN VACUUM PUMP DRIVE HOUSINGAND VACUUM

PUMP(On cOven).

Vacuum Pump Gaskets

Refer to Figure 603A which shows the gasket used between the rear section and the vacuum pump drive housing, also the one used between the vacuum pump drive housing and the vacuum pump (or cover). Reversing the location of these gaskets may result in improper backlash ,and blanking off the oil supply to the pump, causing subsequent failure of the pump. Special care should be taken to insure the proper installation of these gaskets. Note-Misalignment of oil holes in rear section mounting pad and gasket up to one half the hole diameter is permissible and will supply vacuum pump with ample lubrication. Otl Dratn Plpe-Place gasket against pads of oil drain pipe ports on blower and rear sections, then attach drain pipe to pads with the necessary nuts. Oll Pressure Rellef Valve-Insert plunger and spring in the oil pressure relief valve cage. The oil pressure relief valve is located in either of four positions; the oil pump housing; the right side of the accessory section, just above the oil pump; the sump; or at the left side of the pressure chamber. Be sure the plunger seats properly in its cage. If it is evident that the plunger seats improperly, it should be lapped with a very fine grade of grinding compound. After lapping,

the plunger should be blued and checked for even seating. Fit gasket under flange on oil pressure relief valve body, then screw body into case. Be sure that lock nut on valve adjustment screw is tight. not disturb setting of adjustCautlon-Do ment screw in oil pressure relief valve body, However, it may be necessary to alter setting of the screw during first engine run-in to maintain the desired oil pressure. Refer to Chapter VII. Install gasket, and screw acorn shaped cap on outer end of oil pressure relief valve body. Carburetor Eotspot or Adapter (ff Provtded) -Fasten carburetor hotspot or adapter to carburetor mounting flange on rear section with the necessarynuts and washers. Turn the accessory section with stand so that the rear section is facing the floor, then proceed with the installation of parts, as specified in the following: Maln Crankcase Sectlon (Rear Half )-Fit rubber oil seal in groove which is cut in parting face of blower section. Pour a generousamount of engine oil on gears of blower section. Install washers beneath the heads of their respective The lifting links crankcase through bolts. should be fitted on the two longest bolts, at either side of No. 1 cylinder opening. Insert

605

FINAL ASSEMBLY

Fig. 604 -

Checking Clearance between Bottom of Cam Spacer and Top of Cam Hub -

through bolts into their respective holes in rear section of main crankcase, making sure that the longest bolts are fitted through holes on each side of number one cylinder pad. Heavy rubber bands should be wrapped around the bolts to prevent them from dropping through the holes. Mount rear section of main crankcase on blower section, being careful not to damage the oil transfer pipe on Wasp Jr. engines. Fasten rear section to blower section with the necessarv nuts and washers. Crankshaft and Artlculatlng Rod Assernbly - Screw Lifting Eye on the forward end of the crankshaft, and attach the hook of a chain hoist to the eye, then lower the complete assembly into the rear section of the main crankcase so that the crankshaft gear engages with the starter and magneto drive shaft gears. When lowering the complete assembly it should be turned in such a manner as to permit the master rod to fit in its opening, No. 5 on Wasp Jr. and Wasp engines and No. 7 on Hornet engines. The eight articulating rods should also be positioned to occupy their respective openings in the crankcase. Before the assembly is completely lowered, it should again be turned so that No. 1 articulating rod is fnlly extended through its respective opening. Maln Crankcase Sectlon (Front Half )Lower this section over forward end of crank-

Wasp Jr. Engine

shaft to the parting surfaces of the rear half of main crankcase. It may be necessary to drive this section downward (alternately on opposite sides) with a hammer and fiber drift to bring it in with the rear half of main crankcase. forward section of the main Cautlon-The crankcase must be installed in a level position to prevent cramping of the front main bearing. Force the nine through bolts upward through their respective holes in both crankcase sections, using a pry-bar. Cautlon-Do case.

not pry against the blower

Install the necessary nuts and washers. Carn l)rlve Gear (Wasp Ifl and Hornet E)Smear oil in the bore of the cam drive gear and then slip the gear over splines on forward end of crankshaft until it seats on front main bearing. When the gear is being installed it must be turned so that its large spline engages with the large spline on the crankshaft. Care must be taken to see that the oil transfer rings are not damaged while entering the liner of the oil transfer bracket. Carn Drlve Gear (Wasp Jr. Engtnes)-First insert cam drive gear key in the slot provided in the crankshaft, using a hammer and brass dnift. Then slip gear over shaft so that its keyway aligns

606

FINAL

ASSEMBLY

with key in crankshaft and, at the same time, -"rtr th"e cam reduction gear so that its marked l"otft lutt* tr"t*een the t*o marked teeth of the cam drive gear. Cam Otl Feed Braeket (Wasp Jr. Engl+el)Stio tt ir bracket over for*ard end of crankshaft it to the forward section of the main ;A il*e with the necessary nuts or fillister "ru"["ut" A gasket shoulcl be used where the ft"ua ."t"*t. oil feed pipe attaches to the crankcase.

Cam Reductlon Gear (Wasp and Eornet)Install the cam reduction gear in its bushing in the front section of the main crankcase with spacer between it and the bushing flange. It is important to mesh the cam driv_egear,,cam_reduction gear and cam in correct relationship. The marked tooth on the cam drive gear engages with the two marked teeth on the cam reduction gear. The two marked teeth on the_cam engage the marked tooth on the cam reduction gear pinion.

Carn and Cam' Spacer iWasp Jr. Englnes)S*"ut oit in the bole of the cam drum; ther! slip "urn on"t forward end of crankshaft and sleeve drive gear un!il it is properly seated' ;f-;fi The two mark-ed teeth on the cam rim must ""n"e" *itft the marked tooth on the piryorl of the gear while No. 1 articulating -rod ""il?"a"ction i" il r""tt a position that No. 1 piston would be at top dead center. If a floating ring type cam oil feed bracket is used, be sure that the oil transfer tFqt are.prPperly centered in bracket before cam is installed' Smear oil in the bore of the cam spacer-; then spacer over forward end of crankshaft until slip ^reais on top of cam drive gear sleeve. Check it betiveen bottom of cam spager-?nd .i"uiu"." hub, using feeler gage (seeFig. -60+). cam of top Adj".tt"ent of this clearance may Ue madg .bI srinaine spacer on cam drive gear upon which 6am hub r6sts or by installing a thicker spacer'

Bearlng Plate (Geared Englnes)Smear oil around inside of reduction drive gear liner and then install bearing plate on front parting face of forward crankcase section. When assembling this plate on Hornet engines having a governor drive gear attached to the forward end of the cam reduction gar, it is gear as important to mesh the cam reduction "Cam Redescribed in the paragraph entitled duction Gear". Insure that bearing plate is evenly seated, and secure it in position with three flat head screws. Reductlon Drlve Gear (Geared Englnes)Smear internal splines of reduction drive gear with oil and assembleon the front of crankshaft, using the Reduction Drive Gear Pusher (see Fig. 605). Install reduction drive gear lock washer and lock nut, and tighten, using the Reduction Drive Gear Nut Wrench. Lock nut in position by bending up tab of washer.

Fig. 605 -

I'nstalling Reduction Drive Gear

Checklng Plnch Ftt of Thrust Bearlng Cover (Direct Drlve Englnes)-Before assembly of the front section on the engine, it is important to check the pinch fit of the thrust bearing cover against the outer race of the thrust bearing, unless this has already been done during inspection and the same thrust bearing is to be rrsed. The following procedure should be followed: Install cover in position on front section and tighten the nuts. Turn the front section over and measure at several points, the distance from the shoulder of the liner, where the rear face of the thrust bearing rests, and the point on the cover directly forward. Next measure the width of the thrust bearing outer race and the tab spacer (if used) which rests against this race. The total of these two measurements should be from .004" to .008" greater than the distance from the cover to the rear shoulder of the liner. Adjustment may be made by either grinding the present spacer or installing a new thicker spacer. On engines having the steel ring riveted to the rear of the cover, the pinch fit may be reduced by removing the rivets which hold the steel ring to the cover and wet grinding the face of the ring which mates with the cover. The pinch fit may be increased by facing the flange of the cover sufficiently to afford the necessaryfit.

607

FINAL

Fig. 606 -

ASSEMBLY

Installing Cylinder

Front Sectlon (Dtrect Drlve Englnes)-Smear oil on front main bearing, propeller oil transfer rings (if provided), and cam lobes. Place front section over forward end of crankshaft, and rest it on parting face of main crankcase. It may be necessary to drive the section downward (alternately on opposite sides) with a hammer and fiber drift to bring it in with the main crankcase. front section must be installed Cautlon-The in a level position to prevent the propeller oil feed pipe (if provided) from being damaged. On the Wasp Jr. B3 insure that the two ends of the rocker oil manifold fit into theif holes in the front section. On Wasp H1 and Hornet E engines, it is very important that the propeller oil transfer rings do not become damaged when installing the front section. In some cases it witl be necessary to insert a long thin rod between the parting surfaces of the front section and the front section of the main crankcase to compress the oil seal rings so that they will enter the liner in which they bear. Fasten front section to main crankcase with the necessary nuts and washers. Thrust Bearlng and Sllnger (Dlrect Drlve Englnes)-Install thrust bearing in position in

its liner. On Wasp Jr. engines the small spacer should first be inserted between the thrust bearing and the propeller oil transfer ring carrier. Screw Lifting Eye on forward end of crankshaft and attach the hook of a chain hoist to the eye. Raise the crankshaft slightly, then insert a piece of fiber between the rear crankshaft counterweight and rear section of main crankcase. Remove chain hoist hook and Lifting Eye, then drive thrust bearing into liner, using a suitable sleeve type drift. Place the thrust bearing slinger over forward end of crankshaft and seat it against the bearing. srrre that slinger is properly Cautlon-Be centered over the shoulder on the crankshaft. Thrust Nut (Dlrect Drlve Englnes)-Screw thrust nut on crankshaft and tighten it securely with the Thrust Nut Wrench. The crankshaft may be prevented from turning by using the Crankshaft Spline Wrench. Remove fiber which was inserted under counterweight of rear crankshaft. crankshaft Plstons and Cyllnders-Rotate until articulating rod of the master rod cylinder is at its top dead center position. Fit rubber oil seal around radius under cylinder hold-down flange of each cylinder. Insert correct piston

608

FINAL ASSEMBLY

Fig. 607 -

Installing Oil Sump

pin through piston and bushing in arJiqulatlng iod. The piston pin should be well oiled before insertion. It is important that each piston and piston pin bear the same number as that of the -ylinder in which the piston is to be installed. Each cylinder is numbered on the forward side of the hold-down flange, and each piston is numbered on one of the piston pin bosses. Each piston pin is numbered on one of the plugs at the end of the pin. It is common practice to install the piston and pin with their numbered sides toward the front of the engine. In any event, a uniform procedure should be adopted. Coat the cylinder walls, piston and rings with a generous amount of oil. Stagger the ring gap_s around the circumference of the piston. Lock the Ring Clamp over the piston and rings and slide cylinder over piston and into place against its mounting pad. The cylinder should be fastened to the crankcase with at least one nut before installing other cylinders (seeFig. 606). After installing the master rod cylinder, the remaining cylinders should be installed in the same manner, following around the engine in a Screw cylinder counter-clockwise direction. hold-down nuts on studs, then check alignment of each pair of adjacent cylinders, by placing a straight edge across their exhaust and intake port flanges. The four ports on each pair of cylinders should be within Yn" alignment.

Tighten the cylinder hold-down nuts, using the Cylinder Hold-down Nut Wrench. not tighten nuts excessively, Cautlon-Do as in so doing the studs may be stretched or broken. The recommended torque for tightening cylinder hold-down nuts is 300 in lbs. for both the necked and the unnecked type studs. For engines which incorporate inter-cylinder oil drain pipes or oil pressure pipes, slip the hose connection into position, and secure with clamps or wrap lock. Oll Surnp-Place a gasket cn each mounting flange of the oil sump; then secure sump to its resp-ective mounting pads, using four washers anil nuts (see Fig. 607). The proper spacers if used, should be placed under the washers on the two rear studs. Screw oil drain plug into bottom of sump and tighten. Oll Suctlon Ptpe-Insert oil strainer into oil suction port at rear of sump. Place gasket over oil suction pipe mounting pads on rear section and sump, then fasten the pipe in position. On Wasp Jr. 83, Wasp H1 and Hornet E engines, this will also apply to the rocker box scavenge pipe from the lower compartment of the sump, excepting that there is no strainer at this location.

609

FINAL ASSEMBLY a shroud is used Cyttnder l)eflectors-Unless for cooling purposes during the run-in of an engine after overhaul, it is recommended that the cylinder deflectors be left off until after runin of the engine. For complete instructions on installing cylinder deflectors see Chapter VIII.

pressure pipe to the tee connection at No. 1 cylinder and to the oil outlet at the lubricator pump on the rear section.

both front and rear Ienltlon Manlfold-Attach sf,ielding manifolds to the main crankcase with the necessary nuts or cap screws. On the rear manifold, it is first necessary to dis the two sections before installing it on the engine. After the manifold has been installed in position, the two parts may be ed together with the large union nut.

With CrankshaftWrench, turn crankshaft anticlockwise until the piston in No. 1 cylinder is at the exact top dead center of the compression stroke (both valves closed). Set the clearance between adjusting screw ball and valve stem to .060" for Wasp Jr. and Wasp engines and .078" for Hornet engines, for both inlet and exhaust valves in No. L cylinder. To perform this operation, use Valve Adjusting Screw Wrench and feeler gage. Turn crankshaft anti-clockwise nearly one revolution until pointer is near inlet open mark (I.O.) on front section of direct drive engines and bearing plate of geared drive engines, then insert .0015" feeler gage between adjusting screw ball and stem of No. 1 inlet valve. Tap Crankshaft Wrench in an anti-clockwise direction until a slight pressure is exerted against feeler, or until inlet valve is just ready to open, then note position of pointer with respect to inlet opening mark. Turn cranlcshaft anti-clockwise until pointer esexhaust valve closing mark (8.C.), then insert .0015" feeler gagebetween adjusting screw ball and stem of number one exhaust valve. Next turn crankshaft clockwise until pointer is in a vertical position. Tap wrench in an anticlockwise direction until pressure on feeler begins to release, then note position of pointer with respect to exhaust closing mark. The following table contains the opening and closing positions of the valves.

Intake Ptpes-With the necessaryflange, gland nut and rubber packing in place on the intake pipe, place pipe in position and screw gland nut Ioosely into the blower. Install copper gasket at cylinder intake port with the split side toward the port, then fasten intake pipe flange to cylinder heaii with cap screw and nuts. screw and nuts evenly to Cautlon-Tighten prevent distortion at the flange. Tighten gland nut at blower end of pipe, using the Intake Pipe Nut Wrench. not tighten excessively, as in Cautlon-Do so doing the end of the intake pipe may neck down. Push Rods and Covers-Wasp Jr. engines, which incorporate either on Automatic Valve Lubricator or the One-Shot System, require the use of a drilled type push rod ball end at the tappet ends, only, of the push rods for the following cylinders: Inlet #L,2,3, 8, and 9 cylinders; and Exhaust #L, 2, 3, 4, 7, 8, and 9 cylinders. Plain type ball ends should be used on both ends of the remaining push rods. Smear oil on the ball ends of each push rod, and then insert push rod in cover. Rotate crankshaft until tappet which actuates push rod to be installed is fully receded in its respective guide. Depress rocker arm with the Rocker Arm Depressor, and fit push rod and cover into proper position. Be sure that push rod is properly marked and inserted in its correct position with respect to the cylinder number. Tighten gland nut on each end of cover using Push Rod Gland Nut Wrench. The gland nut at the tappet end of the cover should be tightened first. Cautlon-Tighten excessively.

these nuts snugly but not

Prlmer Llnes and Cyllnder Otl Feed PlpesScrew primer line distributor into top of blower section and attach necessary primer lines. Connect primer lines to their respective elbows at the cylinder heads. On Wasp Jr. B enginm, having a valve lubricator system, attach the

Timing Pointer Checklng Valve Tlmlng-Fit over propeller shaft of direct drive engine and to reduction drive gear of geared engines.

Engine Tipe

Inlet Opens (in degrees before top center)

Hornet

20" E.

waspJr. 26"Êie?n. wil-

Inlet Closes (in degrees after bottom center)

zsir. rcir*

77" L.

Exhaust Opens Erhaust Closes (in degrees (in degrees before bottom after top center) center)

zri n. zrl n. 76" E.

srl l. eri r,. 21" L.

Adjustrrrent of Valve Clearances-The valve clearances are adjusted in a sequencewhich conforms to the firing order of the cylinders, (i.e. 1, 3, 5, 7,9, 2, 4,6, 8). Turn the crankshaft anti-clockwise until both valves of cylinder No. 1 are closed and the piston is at the exact top dead eenter of the compression stroke. Insert a .010" feeler gage between the valve tip and the adjusting screw ball. Loosen lock nut and back off or turn down on valve clearance adjusting screw, using Valve Adiusting Screw Wrench, until .010" clearance is obtained. Retighten the lock nut, being careful not to turn the adjusting screw. the adjusting screw lock nuts Cautlon-When are tightened an excessivepressure should not be exerted as such will pre-load the adjusting

610

FINAL ASSEMBLY

Fig. 608 -

Timing Marks on Scintilla SB-9R Magneto

screw and breakage is apt to occur in subsequent running. 275 in.-lbs. is considered the proper torque limit for tightening. Do not strike wrench with any object while tightening. After adjustment of the valves in Number 1 cylinder, the crankshaft should be turned with the CrankshaftWrench so that the piston in Number 3 cylinder is at top dead center of its compression stroke. Adjust valves in same manner as described for Number 1 cylinder. This should be accomplished at the remaining cylinders in the firing order previously given in this section. Be sure that each plston ls at exact top dead center. After completion, rotate the crankshaft two complete revolutions and recheck the clearances. Any valve clearancesfound below .010" should be reset to this figure, but.a greater clearance should not be disturbed unless obviously excessive. Tfunlng and Synchronlzlng Magnetos to Timing Pointer over propeller shaft Englne-Fit of direct drive engines and to reduction drive gear of geared engines, if not already installed. With Crankshaft Wrench turn crankshaft anticlockwise until the piston in Number 1-cylinder is on the compression stroke, (both valves closed) and the Timing Pointer aligns with the specified spark advance mark on the nose section or the bearing plate.

Fig. 609 -

Timiig Pointer for Timing ing Magnetos

and Synchroniz-

Turn magneto shaft until timing marks on the large distributor gear align with the timing marks on the inside of the front end plate. At this time the running segment on the distributor or rotor should be in a position opposite the Number 1 distributor block electrode, and the breaker should be just opening. Connect the Timing Light across the breaker s of the magneto or insert a .0015" feeler gage between the breaker s. Turn magneto shaft slowly until the breaker s begin to open and the timing light goes out, or the feeler gage can be removed with a slight pull. This should occur when the straight edge against the cam step falls in line with the marks on the breaker housing (see Figs. 608 and 610). The straight edge should coincide with the timing marks on the breaker housing, when the s are just breaking. However, a distance of Ysz"between the straight edge and the timing marks is permissible. If this distance is exceeded, refer to the instructions in Chapter XIV, "Magnetos". Turn magneto drive rubber coupling until it can be engaged in its mating flanges without causing the rnagneto shaft to turn. Engage rubber coupling and fit magneto over dowel pins in mounting pad and fasten magneto to engine rear section with the necessary cap screws. When both magnetos have been installed, turn crankshaft 90' in a clockwise direction, then reverse rotation until the feeler gage can be removed from between the pdints with a

611

FINAL ASSEMBLY

\-

\-

slieht pull, and note the position of the Timing Po-intei with respect to the specified advance mark on the front section or bearing plate (seeFig. 609). The points of both magnetos should break simultaneously when the Timing Pointer aligns with the timin_g-mark on the front section or plate. If the s do not break at this point, adjustment should be made in accordance with instructions in the next paragraph If the points break before the pointer aligns with the timing mark on the front section, remove magneto, turn rubber coupling clockwise one or two notches; refasten magneto to engine rear section; recheck timing as previously out Iined. If the points should break after the pointer aligns with the timing mark o_n-the front section, the above procedure should be followed except that the rubber coupling should be turned anti-clockwise one or two notches. Due to the fact that the coupling has 19 notches on one side and 20 notches on the other, a very fine adjustment can be made. Make a final check to see that the straight edge is in line with the step of the cam and the marks on the breaker housing when the points are just starting to open.

no circumstances should an Cautlon-Under American Bosch magneto and a Scintilla magneto be used together on the same engine. Magnetos wtth Steel Coupllngs=Mqgnetos which have steel couplings should be timed to the engine as previously outlined for the rubber type coupling, with the following exceptions: To engage and fasten each coupling, turn it around until it slips into place over the coupling drive gears and secure with lock ring. To disengageeach coupling, remove lock ring and slip the coupling backward toward the magneto. . This operation may be performed without removing magneto from rear section. To retard magneto timing by means of the coupling (when breaker s open early) disengage coupling, turn it anti-clockwise one or two teeth, engage coupling and secure it with lock ring. To advance magneto timing by means of the coupling (when breaker s open late) the instructions in the preceding paragraph should be complied with except that the coupling should be turned clockwise one or two teeth.

t-

R e d D o t o n C a m Indicates No. 1 Lobe

I

\-

Edge Straight Placed Acros Step of Timing Muet Collar Coincide Marks "T" with Timing when Points

&i,I';,fi B'i*f"f,B.""

"E" give correct Gap. limits Permisible are on either side of l;!" "T". Timing Marks

Fie. - 610 -

Rear View of American Bosch SB9RU-3 Magneto Showing Timing Marks

YIEW L@KINO AT UAaNE|O ENO FIRINO OPzEP- l-3-5-7-9-2-1-6-A

Fig. 611 -

Wiring Diagram

6L2

T.INAL ASSEMBLY FINAL

OPERATIONS

Remove Timing Pointer and Crankshaft Wrench from propeller shaft of direct drive engines, and the Timing Pointer and the Reduction Drive Gear Timing Wrench from geared engines. On direct drive engines fasten propeller thrust bearing cover to the front section with the necessary nuts and washers. installing cover plate, be Cautlon-When sure that the drain holes in the plate match up with those in the nosesection. Magnetos-Assemble the breaker covers on the magnetos, and fasten with the knurled screws. Secure the fastening serews with wire clips. Install the distributors in their correct positions on the magnetos. To insure correct positioning, the numbers "4 and 6" on the righf distributor block should be next to the numbers "4 and 6" which appear on the main cover. Fasten blocks with the metal straps and lock with wire clips. Ignltlon Wrlng-It is irnportant to check the ignition wiring. The numbers on the distributor blocks indicate the serial firing order of the magneto. The firing order of the engine is 1, 3, 5,7, 9,2, ((1" 4, 6, 8. Therefore, the cable from terminal connects with No. 1 cylinder; the cable from terminal "2" connects with No. 3 cylinder; the cable from terminal "3" connects with No. 5 cylinder, etc. The right magneto fires the front spark plugs, and the left magneto fires the rear spark plugs (seeFig. 611). The booster ((H" wire is connected to the terminal marked on the top of the main cover, and the ground wire from the magneto switch to the terminal marked ttP". Rocker Box Covers-Fit a gasket on the mounting face of each rocker box cover. Fasten covers on the rocker box housings with the spring clamps or nuts. Reductlon Gear Eouslng (Geared Englnes)Place the Crankshaft Wrench on the propeller

shaft and screw Lifting Eye to the end of propeller shaft. Attach the hook of the chain hoist to the eye. Pour a liberal coating of oil on reduction drive gear and intermediate governor drive gear assembly, (if provided). On Wasp and Hornet engines, install tee pipe connection and oil pipes connecting front of sump to oiler bracket. On Hornet EG series engines used in installations where the propeller blades close to the ship, lower reduction gear housing on to front rnain crankcase so that wide spline on propeller -location; shaft is 20" ahead of the master rod that is, between numbers 7 and 8 cylinders. It is recommended that the Superintendent of Overhaul be consulted in this respect. Rock propeller slgft slighlly to jnsure proper meshing of gears. Secure with hold-down nuts. Instaii propeller shaft oil feed pipe and locator, and screw on locator cap. Propeller Otl Fe_edPtpe-When assembling the nose section on Wasp H1 engines, trouble has been experienced because the propeller oil feed pipe has been forced into the nose section, thus cutting off the supply of oil to the tappets. To prevent this, an additional shouldei has been added to the pipe and it is recommended that the new type pipe be used on all earlier models. On all other Wasp and Hornet engines the propeller oil feed pipe should be aligned with the oil pipe hole in the nose section so that it will not become damaged when nose section is lowered onto the front main crankcase section. Spark Plugs-Install spark plugs in front and rear of each cylinder -Attach and tighten with Spark Plug Wrench. each i[nition wire tb its respective spark plug. I4spectlon of Assernbled Engtne-It is considered a good practice to make a thorough visual i{rgpection of the assembled engine. See that all external nuts and fittings are tight, and that no gaskets or safety wires have been omitted.

613

FINAL ASSEMBLY

TOOL LIST Wasp

Wasp Jr. Tool No.

B

82

B8

EI

ET. G

D

.PWA-2240 x ADAPTER _ (Usewith PWA-2239) .. x . .PWA-249 . . Compressing. Ring Piston CLAMP . .PWA-13 Compressing... PistonRing cLAMP Piston Ring .- Compressing. . . . .PWA-184 CLAMP x ....PWA-455 DEPRESSOR - R o c k e r A r m .

x x

x x

x

x

x

x

x

x

x

x

x x

x x

x x

x

x

x

x

x

Tool Nanre

\-

Ilornet

Lifting, for Geared Crankshafts. . PWA-662 Lifting, for Geared Crankshafts. . PWA-1079 -Lifting, . . . .PWA-520 #30 Spline. . . . - Lifting, #40 Spline. . . . . . . .PWA-1332

DYE DYE DYE DYE -Lifting, . . . .PWA-1333 DYE #50 Spline. . .. - Starter Shaft Bushing Flush Pin. TAM-1113 GAGE EANDLE - Cylinder Hold-down Wrench (Use EANDLE

-

with PWA -2299 and PWA-2240) . PWA-2398 Cylinder Hold-down Wrench (Use with PWA-2239 and PWA-2240). PWA-241L

POINTDR -Timing, POINTER -Timing,

1 3 0S p l i n e . . . . . 140Spline... . .

POINTER -Timing, (3:2 red.). PUSEER - Reduction Drive Gear. LIGET-Magneto.... WRENCE - Crankshaft, #30Spline WRENCE - Crankshaft, #40 Spline WRDNCE - Crankshaft, #50 Spline

TIMING

...PWA-85

x

x

x

E . G 82. GI D 3 . G

x

x x

x

x x

x

x

x

x

x

x

x

x x

x x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x

. . .PWA-115

x

' .PWA-535

x

x

x

x

. . .PWA-465

x

x

x x

x

x

x x

x

x

x

x

x

.PWA'24L7 ....PWA-112

x x

x

x

x

x

... .PWA-155 .. . .PWA-197

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

I

x

x

x

x x

x

x

x x

x

x x

x

x

x x

x

WRENCE WREITCE -

. . PWA-237 Intake Pipe Packing Nut . . PWA-144 Intake Pipe Packing Nut Push RodTube Gland Nut. . . .' .PWA'2434 Reduction Drive Gear (Timing) . .PWA-1636

x

x

x

WRENCE -

..PWA-1093

x

x

x x x x

x x

x x x

x

I

WRENCE

-

WRENCE

-

WRENCE

-

WRDNCE

-

WREITCE WRDNCE -

Cylinder Hold-down Cylinder Hold-down with PWA-2239 and Cylinder Hold-down with PWA -2239 and Cylinder Hold-down with PWA-2239 and

Nut

Nut (Use PWA-2240). PWA-2006 Nut (Use PWA-2240) . PWA-2397 Nut (Use PWA-2240). PWA-2399

Thrust Nut. . Nut.. WRENCE-Thrust \PRENCE -Thrust Nut.. WRDNCE WRENCE

-

WRENCE

-

WRDNCE

-

WRDNCE

-

WRENCE

-

WRENCE WRDNCE WRDNCE

-

WRDNCE

-

. . PWA-186

Thrust Nut. . Thrust Nut. . Torque (600 in. lbs.) .

x

x x

x

x

..PWA-1092

x

..PWA-1084 . .PWA-1094 . .PWA-1095 PWA-2239

. . . .PWA-1075 Valve Adjusting Screw . . .PWA-1398 Spark Plug - ry*" hex. Bendix Plug 7B - V8" hex.. . . . .PWA-1441 B e n d i x P l u g 6 S 6- 1 4 " h e x . . . . . . P W A - I 4 7 4 ..PWA-1684 BendixLS1O - r'/8"hex.. . PWA-1696 hex. . LS L,4'8 Aero ,4" LS hex. BG LS 3AB Aero 94" 321- !,4" hex., and AN tYPe . -PWA-2254 plugs - ,4" hex...

I

x x

x x x x

x x x x

x x x x

x x x

x x x

x

x

x

x

x x x

x x

x x x x

x

x

x

x x

x x

x x x x x x x

x

x

x

x

x x x

x x

x

x

x x

x x x x

701

CIIAPTER VII

RUN-IN OF ENGINES AFTER OVERHAUL GENERAL After an engine has been overhauled it is essential that it be run-in to seat the piston rings, burnish certain other new parts which may have been installed and, at the same time, to insure that the engine's performance is satisfactory. In most casesit is neither necessarynor desirable to endeavor to measure horsepower to a fine degree in the field. There are many variables which affect horsepower, and it is not feasible for the average overhaul base to set up the complete equipment and the personnel necessary for very close horsepower measurement. Where an engine has been overhauled as recommended in the preceding chapters of this Manual, and if the carburetor and magnetos have been overhauled, and tested previous to installation on the engine, it should develop essentially the same horsepower as when new. A check on manifold pressure and R.P.M., using a calibrated test propeller and correcting for carburetor air temperature, will render a sufficiently close check on horsepower for mnst purposes.

By the same token, it is not generally practical fuel or oil consumptlgn to tiy to measure specific (lbs./H.P . /br.) in the field. It is advisable, however, to check the grosstfuel consumption in gallons (or pounds) pei hour, and the gross oil consumption in quarts (or pounds) per ho_ur,at cruising horsepower (fuel consumption also at rated power) to make sure that these consumptions are within the normal range. Measurement of the oil flow through the engine is not considered necessary after overhaul, as the flow will automatically fall within the proper limits, if various fit and clearance recommendations are followed. An oil constumption and temperature check is considered sufficient. In the event that it is desired to attempt an extremely close measurement of horsepower on field test stands, the various correction factors and detailed procedures are described in this chapter.

TEST HOUSE

\_

The test house may be segregated into the following three parts from a design standpoint: engine compartment with mounting stand, cooling air intake and exhaust stacks or ducts, and control room. Mountlng Stand - It is desirable that the mounting stand be enclosed. An enclosed stand is advanfageous, not only from the standpoint of quietness and convenience, but also because it affords protection to the workmen who mount and dismount the engine. In addition, it is of distinct advantage, particularly in cold climates, for ready engine starting and proper temperature control. Torque stands are not recommended as overhaul test equipment, in view of the necessity of continual calibration and because measurement of the actual horsepower output is not essential. It is also difficult and expensive to construct a torque stand which is entirely free from excess rigidity. Severe rigidity of mounting stand structure should be avoided. The construction should simulate, as nearly as possible, the flexibility inherent in the average airplane structure. In this connection, the suspended type mounting has been found very advantageoust. With this design the entire assembly of engine mount 4qd a ing drum is suspended by means o{ fbur Ioops of slranded steef cable, two at each end of [he drum. Each loop is attached to anchors with rubber blocks set in the corners of the roof and side walls. The anchoring of the engine

mount assembly is effected by two loops of similar cable, one at each end of the drurrr. These loops are also attached to anchors with rubber blo-cksset in the floor, directly under the assembly. Turnbuckles are provided in each loop of cable so that the propel tension for the desired rigidity may be obtained. In order to hold the engine mount assembly against the propelle-r thiust, the two anchoring cable loops on each end of the test stand are crossed; that is, the loop from the rear of the drum is anchored at the front of the test house and the loop from the front of the drum is anchored at the rear of the test house. This arrangement is illustrated in Fig. 701. The engine mount assembly is constructed in two parts - the engine mount prope-r and the ing drum. The in-g drum- consists of a liollow steel cylinder, 8 ft. long andS9th in. in diameter, constructed of r/z in. steel. The ends of the cylinder have a 4 in. inner circular flange made from lft in. steel to strengthen the ends and form an anchorage for the tubular engine mount. The engine mount is made of welded steel tubing and designed to accommodate adapter mount plites for di-fferent models of engrnes. The adapter mount plate for single row engines (Part No. TC-51259) is illustrated in Fit. 702. This construction per-it.- a ruggg.d engrnemount and also the maximum of accessibilitf to the accessory sggtio.nof the engine. This engine mount assembly is heavier than is required for single row engines but with the trend tbward highei power an-d larger engines a stand

702

RUN-IN OF ENGINES AFTER OVEREAUL

Fig. 701 -

Typical Engine Test Chamber

703

RUN.IN OF ENGINES AFTER OVERHAUL of this type, if constructed, will be found advantageous for testing larger engines. If the test stand is intended to only single row engrnes during test the ing drum may be of lighter construction, consisting of a hollow steel cylinder, 6 ft. long and 30 in. in diameter made from % in. steel. The ends of the cylinder may be closedwith Yain. flanged plates. Englne Cornpartrnent - The engine compartment may be either round or square in cross section, preferably round. It is also permissible that the compartment be round only at the central portion which envelopesthe engine and propeller. If this type of construction is used, the transition from the square to the round section should be gradual, and shaped to insure a smooth flow of air over the engine. The advantage of a cylindrical-shaped engine room is that it contributes to smooth air flow. A disadvantage is that a specially constructed stand is necessary for working around the engine. It is recommended that the engine compartment have cross sectional dimensions of at least 16 ft. x 16 ft. It should be as free as possible from obstructions which might interrupt or deflect the propeller blast. Fig. 701 illustrates this point. Obstructions that will interrupt or deflect the propeller blast usually cause eddying and surging and result in a rough running engine. Whereas the aforementioned dimensions INTAKE

are greater than the minimum values required for the types of engines discussed in this Overhaul Manual, they should be used if the space is available in view of the possibility that a more roomy test house will be needed for larger, more poweiful engines at a later date. It is much easier and less expensive to build the large test house at the start than to enlarge a smaller one later on. In any event, the crbss sectional dimensions should not be less than L2 ft. x 12 ft. in order to provide a three foot propeller tip clearance. The length of the engine compartment proper depends upon the type (round or square) of engine compartment constructed. In any case il should be long enough to cover the engine stand with the engine mounted, and provide an additional space-in front, sufficiently large to permit working- on the engine prior to mounting on the stand. In the caseof the compartrhent with the round central portion, the transitional section from square to round may be the determining factor. In cold climates, roll type doors should be provided to close off the engine compartment from the air inlet and exit stacks and a heating system should be installed. Electric liehts with suitable reflectors may be sunk in the iides and roof of the engine room. A two ton chain fall and track should be suspended from the roof, directly over the engine.

AND EXHAUST AIR STACKS

The intake and exhaust air ducts or stacks may be either horizontal or vertical, but in either case should have a cross sectional area equal to the engine compartment. The horizontal type of intake duct is preferable because it provides a smoother flow of air to the propeller and engine. The vertical exhaust stack is preferable because the exhaust gases, together with the heated cooling air, are thrown upward and more quickly and completely dispersed in the atmosphere. The combination of the horizontal intake and vertical exhaust stack forms an "L" shaped test house embodying the desirable qualities just described. The horizontal vanes showing to the rear of the engine compartment in Fig. 70I are provided to deflect the exhaust air up through the vertical exhaust stack. However, such vanes are not essential where the air exit is dimensioned and contoured in manner conducive to free, smooth air flow.

If, for some reason, the use of a vertical intake stack is necessary,the propeller should be at least 10 feet from the inner edgeof the stack opening. The length of the ducts or stacks, which are used primarily to deaden the noise from the engine and propeller, depends upon the type and extent of soundproofing desired for the particular Iocality where the test house is located. Whether or not immediate soundproofing is intended, it is good policy to investigate the possibility of such requirements for a future date and to make the necessary provisions for the incorporation of soundproofing with minimum structural changes. The matter of soundproofing is too specialized and detailed to permit it to be covered in this manual. If experts on the subject are not available locally, Pratt & Whitney Aircraft will gladly offer suggestionsupon request.

CONTROL R O O M The control room should be located adjacent to the engine compartment and so that the operator is behind the plane of the propeller. It should be of sufficient size to house all controls, instruments, and equipment necessary for the

operator to manipulate while an e:rgine is running during test. The illustration, Fig. 703, shows the inlerior of a control room. The room should be provided with a heating and ventilating system and special attention should be given

704

RUN.IN OF ENGINES AFTER OVEREAUL

f-rr ree 2 HOLES

f onn-r-

9 HOLES

tt onruu-4HoLEs THESE SURFACESMUST BE FLAT AND FREE FROM BURRS. MATERIAL-BOILERPLATE REE-TC-5t259

______*t-8

-.*

HoLLorv I fi-raxI uor.rc SCREW POINT ALLEN SET

-,*--l 45O CHAMFER TO ROOT DIA. OF TH,DS.BOTH ENDS.

\n

w

DRILL STUD TO ROOT DIA. OF TH,D TO RECEIVESET SCREIV.

| -ro rx'o.

jl-ro rx'o I ore.s.A.E.

SCREW STOCK

DETAIL OF STUD AND SET SCREW LOCATION- 2 REQUIRED.

Fig,.7O2 -

Adapter Mount Plate for Single Row Engines

705

RUN.IN

OF ENGINES AFTER OVEREAUL

to eliminating oil and fuel vapors. A lighting system which will completely light the control rbom, and especially the instruments, shogld be installed. This system should be installed with care and explosion-proof fixtures used throughout. A window and door between the engine compartment and control room should be provided. The window should be located opposite the engine, behind the rotating plane of the propeller and should have two plates of heavy glass. The doorway should have double doors. A desk or writing board should be built below the window and the mountings for the engine instruments and controls so that the operator may have a good view of the engine at all times while manipulating the controls, observing the instruments and recording data. It is suggestedthat the engine control station be provided with the instruments, controls and equipment described in the following paragraphs. Tachometer - A tachometer should be provided which reads in revolutions per minute (300 - 3600 R.P.M.) combined with a manually operated revolution counter. Stop Watch - A stop watch reading 0-100 seconds is advantageous for checking fuel consumption. Fuel Pressure Gage - A fuel pressure gage should be connected to indicate the pressure at the carburetor 0-15 lbs./sq. in. (0-1 kg./sq. cm.). Oll Pressure Gages - Oil pressure gages with ranges suitable for the following pressures should be installed: 1. Main Pressure- 0-300 lbs./sq. in. (0-21 kg./sq.cm.). 2. Governor "Nose" Pressure (for engines equipped with nose mounted governor) 0-300Ibs./sq. in. (0-21 kg./sq. cm.). Oil fnlet and Otl Outlet Ternperature Gages - These gages,with graduations of 50' - 220" F . ( 1 0 ' - 1 0 4 ' C . ) a n d 1 0 0 ' - 2 9 0 "F . ( 3 8 ' 143' C.), should be permanently connectedin the oil lines. Alr Inlet Temperature Gage - Air inlet temperature gage(-30'- 150' F.) (-34'- 66" C.) should be located in the air duct to the carburetor to indicate the temperature of the air just as it enters the carburetor. Manometers - Two manometer tubes should be installed. These tubes should be capable of indicating 60 in. Hg absolute pressure. One mercury manometer should be connected with the blower rim and another may be connected with No. 1 intake port. The manometer indicating No. l intake port pressureservesas a check on the blower rim manometer during test.

Clock - A clock should be installed in the control room or at the control station so that the operator may check the running time. Potentiometer-pyrorneter, or Pyromllllvoltrneter, and Thermocouple Swltch - A means of accurately determining cylinder head temperatures should be installed. A thermocouple switch with sufficient s for at least four thermocouple connections should also be installed. Barometer and Chart - A barometer should be installed in the control room together with its temperature correction chart to allow the operator to determine the true barometer. Psychrorrreter and Chart (Opttonal) - A psychrometer and chart may be provided in the control room to determine the moisture content of the air. Manual Controls for Englne - All manual controls for the engine (throttle, mixture control, blower gear ratio selector valve, starter) should be conveniently located at the control station. These controls should be of robust construction and provided with locks to secure the controls at their desired positions during the test. Fuel Flowmeter or Equlvalent - A fuel flowmeter which reads directly in pounds of fuel flow per hour is helpful in quickly determining _the fuel consumption. The fuel flowmeter should be calibrated for the specific gravity of fuel used. Fuel flow may also be determined by using a tank on a weight scale, or a volume gage. This is further discussedunder "Fuel System". FueI Wobble Pump - A manually operated wobble pump shoulil be connected to the fuel inlet line of the engine. This pump is provided carburetor prior to positively supply fuel to the "FueI System". to starting as described under Prlmlng Pump - A manual or electric priming pump-starting. should be installed in order to facilitate The use of this pump is described cold in the Operators Handbook. OtI Wetght Tank - A weight tank, connected into the engiire oiling system, should be mounted on a platfoim scale so that oil may be weighed and the consumption thus checked when desired. "Oil The arrangement is discussed further under System". Otl Wobble Pump - A manually operated wobble pump should be connected to the oil inlet line of the engine. This pump is provided to positively supply oil to the engine prior to starting as describedunder "Oil System". Ignltlon Swltch - An ignition switch should be provided which will allow the operator to cheCk the operation of each magneto separately.

706

RUN.IN OF ENGINES AFTER OVEREAUL

Fr {J

"*d t

O h fi

II Fb! f-.

\---

707

RUN.IN

OF ENGINES AFTER OVERIIAUL

The ignition switch should also have an off position which will positively cut-out the ignition system of the engine. Flre Extlngulshers - The control station should be provided with portable fire extinguishers of the Pyrene (carbon tetrachloride) and Foamite (sulphuric acid and soda) types. A permanent COz system should be installed. Two control valves for the permanent CO2 system

should be installed at the control station, one to operate the system in the engine compartment and one to operate the system for the control room. A third valve outside the test house should operate both the control room and engine compartment systems. Following is a list of manufacturers from whom the foregoing instruments and other equipment may be procured:

LIST OF MANUFACTURERS OF INSTRUMENTS, CONTROLS AND EQUIPMENT 1.

Tachometers

Blanchard Instrument Co. Cambridge, Mass., U.S.A.

2.

Stop Watches

A. R. & J. E. Moylan Co. 264 West 64th Street New York City, N. Y., U.S.A.

3.

Fuel Pressure Gages

American Ashcroft Hancock Co. Bridgeport, Conn., U.S.A.

4.

Oil Pressure Gages

American Ashcroft Hancock Co. Bridgeport, Conn., U.S.A.

5.

Oil Intet and Oil Outlet Temperature Gages

Foxboro Company Foxboro, Mass., U.S.A.

6.

Air Inlet Temperature Gages

Foxboro Company Foxboro, Mass., U.S.A. Taylor Instrument Co. Rochester,N. Y., U.S.A.

7.

Manometers

American Ashcroft Hancock Co. Bridgeport, Conn., U.S.A. Macalaster Bickwell Co. Cambridge, Mass., U.S.A. (GlassU Tubes Ya in.OD x 40 in. long for manometers)

8.

Clock

May be obtained locally

9.

Potentiometer-pyrometer or Pyromillivoltmeter, and Thermocouple Switch

Leeds & Northrop Philadelphia, Pa., U.S.A. Lewis Engineering Co. Naugatuck, Conn., U.S.A. Foxboro Company Foxboro, Mass., U.S.A.

10.

Barometer and Correction Chart

Taylor Instrument Co. Rochester,N. Y., U.S.A. Henry J. Green 1191 Bedford Avenue Brooklyn, N. Y., U.S.A.

11.

Psychrometer and Chart (Optional)

Taylor Instrument Co. Rochester,N. Y., U.S.A. Julien P. Friez & Sons Baltimore, Md., U.S.A.

L2.

Manual Controls for Engine

Simmonds Aero Accessories 10 Rockefeller Plaza New York City, N. Y., U.S.A.

708

RUN.IN

OF ENGINES AFTER OVERHAUL Fischer & Porter Hatboro , Pa., U.S.A. United Aircraft Products Inc. Dayton, Ohio, U.S.A.

13.

Fuel Flowmeters

L4.

Fuel Wobble Pump

15.

Priming Pump (Manual)

The Lunkenheimer Co. Begkman St. and Waverly Ave. Cincinnati, Ohio, U.S.A. Bendix Products Div. Bendix Aviation Corp. South Bend, Indiana, U.S.A.

(Electric)

16.

Oil Wobble Pump

United Aircraft Products Inc. Dayton, Ohio, U.S.A.

L7.

Ignition Switch

Scintilla Magneto Div. Bendix Aviation Corp. Sidney, New York, U.S.A.

18.

Fire Extinguishers


19.

Scales (Fuel and Oil)


The entire test house structure may be built of brick and mortar, or reinforced concrete. In any event, the material should be non-inflammable. Inasmuch as the engine stand ing cables are designed for a maximum tension of approximately 80,000 pounds, the wall and roof

structure should be capable of withstanding this stress with an adequate safety factor. Layouts and detail construction drawings of recorimended test house designs are available and may be obtained from the Pratt & Whitney Aircraft Service Department.

CARBURETOR AIR INTAKE The air intake duct to the carburetor should draw its air from outside the test house. It should have a cross sectional area of at least 38 sq. in. and should be as free as possible from sharp bends or irregularities that might restrict air flow or cause turbulence. The air duct entrance at the outside of the test house should be Iocated so that dirt or foreign material will not be taken in. A preheater, utilizing the heat of two or more exhaust stacks, or a steam radiator, should be provided in the system to supply preheated air to the carburetor. It should be possible to maintain the temperature of air entering the carburetor at 100' F. or more under the lowest outside air temperature conditions for the

SYSTEM

locality. A suitable iarburetor air temp-erature regulaling valve should be qrovided. The preheating system should be so designed as to cause restriction or disturbance to air no apfrebiable flow.- If the preheater is located some distance from the carb-uretor, the portion of the duct between it and the carburelor should be well insulated to prevent lossof heat. The entire intake system should be sufficiently "backfire" pressutes,and a strong to withstand backfire relief valve should be located near the carburetor. A flexible section should be incorporated between the carburetor and the fixed poltion of the intake air duct.

ENGINE EXEAUST SYSTEM The use of an exhaust collector ring is not recommended for the test stand operation. Short stacks are desirable, in that they simplify the mounting of the engine on the stand and permit the operator to detect misfiring cylinders or im-

proper mixtures by watcbing the exhaust flame at each cylinder. The exhaust of two or more cylinders may be conducted through a stove to provide preheated air to the carburetor, as men"Carburetor Air Intake System". iioned under

TEST PROPELLERS From the standpoints of convenience, economy and cooling efficiency, a four-bladed wooden test propeller is recommended for the average test

stand. Suitable test propellers, together with the hubs and attaching parts, are listed in the Pratt & Whitney Aircraft Parts Catalogs.

709

RUN.IN OF ENGINES AFTER OVERHAUL Since the location and characteristics of a test house have considerable bearing on the propeller diameter, a test propeller, as furnished, is somewhat larger in diameter than normally necessary, to permit calibration on the particular test stand where it is to be used. A new propeller should be calibrated on a new engine, or on one that is known to be running satisfactorily, and under atmospheric conditions which are considered average for the location. This is done by trimming off the ends of the blades in small increments until the engine will turn its normal rated revolutions per minute at its rated manifold pressure. The detailed procedure for calibrating, trimming and balancing is as follows: Check the propeller for static balance with regular propeller balancing equipment. If rebalancing is necessary, trim the heavy blade, or blades, as required, referring to the related paragraphs which follow for the proper method of trimming. Install the propeller on an engine which is known to be normal in every respect, and run the engine to get an indication of how much the propeller diameter must be decreased. Atmospheric conditions should be noted so that they can be duplicated, or necessarycorrections made, during subsequent trial runs of the calibration procedure. Run the engine at its normal manifold pressure and note the R.P.M. Due to variables such as temperature, atmospheric pressure,shape of the test house, etc., it is impossible to state, without trial, exactly how much increase in R.P.M. can be expected per inch reduction in propeller diameter on a given test stand. The increase is usually somewhere between 30 and 50 R.P.M., however. It is suggested that the diameter be decreased 1 in. (Yz in. per blade) for the first trimming operation, then the resultant change in R.P.M. noted and used as a guide during further trimming of the blades. The first step preparatory to the actual trimming of the blades is to rest the propeller firmly on a bench or suitable stand and draw a line from the hub to the tip of each blade. This line should be on the front face and along the center of the blade width. Cautlon - To prevent damage to the fabric blade covering, when drawing this line, do not use a hard pencil or sharp pointed tool. Next, mark off one half the desired decrease in diameter on the line drawn along each blade and scribe an arc from this point, the radius of which is Yz the width or chord of each blade. Saw off the blade end to this line and round all sharp corners with a suitable file. Paint the newly exposed wood with a good grade of shellac to prevent the fabric covering from becoming loose and the wood from splintering. Upon completion of the trimming operation,

the propeller must be rebalanced before installation on the engine. Make sure the hub and cone are perfectly clean, then mount the propeller on a regular propeller static balancing stand, using proper arbors and centering cones. The balancing-stand should of course be in a location free from vibrations and drafts. Rotate the propeller slowly and make sure nothing is affecting entirely free movement. Set the propeller so that two blades are horizontal and determine which, if either, is the heavier. Using a draw knife or suitable fiIe, trim the end of the heavy blade, blending the edges in a round shape, holding to the radius as originally scribed. It has been found that a round blade end is much less subject to splintering and wear than a square one. Set the other pair of blades in a horizontal position and repeat the procedure described for the first pafo, then place the propeller so the blades are 45o off the vertical position. Repeat the trimming until the propeller is in perfect static balance. When in true static balance, the mass of one pair of blades will exactly counterbalance the mass of the other pair, even though it may be found that one blade may vary as much as ry' ir'. in length from the other three bladesto obtain this balance. Caution - Do not use any plugs or fillers of any kind, or additional shellac, to obtain balance. As previously stated, the engine should turn its normal rated"R.P.M. at normal rated manifold pressure when the trimming of the test propeller has been completed (refer to engine performance curves for proper values), regardless of the altitude at which the test stand is located. It is permissible that the manifold pressure exceed normal rated manifold pressure bV 3% at rated speedand that the R.P.M. vary plus or minus 50 from rated R.P.M. at rated manifold pressure. If the calibrating is done in cold weather, the propeller should be trimmed to obtain the maxlrnum allowed tolerance on rated manifold pressure and the mlnlmurn tolerance on the rated R.P.M. Where there is a wide difference between winter and summer temperatures, it is desirable to have two test propellers, one calibrated for winter use and the other for summer urie. Quite often the same engine will require a propeller which is up to two inches smaller for winter use than for summer use, to obtain proper manifold pressureand R.P.M. values. A test propeller may eventually become too small for a given model of engine, due to stock which has been removed to overcome damage (splinters, nicks, etc.) which occurred during test operation. In such an instance, it may be found possible to retrim it for use on some smaller or less powerful engine. When wooden test propellers are not in use they should be protected from weather, particularly ice and snow.

7LO

RUN.IN

OF ENGINES AFTDR OVERHAUL

III'ER C FT.EL TA}I€ OTT'TAL FOR FI.ELS OF SES.6 OCTA}C RATIT{GS

STRAilER

THI' YENT "**II

ED?lffrJcHffilI

\

\ t' sAFETy GATE nLvE WITH WEIG}ITT FUSbLC L|t{(

YOI.TE

rLd

ttat

ctuTcn

accaaeaaTa

Ld

FIIL

E?ER

clutct

3-WAY VALVE OPTONAL OITAINING

M€THODIS OF FI'EL FLOW

rcIl," '

INSTRUMENT FANEL

OIJT3DE AN NTAKE .E: + To cAR$nEToR

CAR8. AN

VENT COCK

FULFLO FILTER MOOEL WFDS wtTH il3CVC FILTER UNITS. DRAIN COCK

OIL RADIATOR

gATER TO SEWER

STEAMI

Fig. 704 -

Piping Diagram of Typical Test House

usE r- P|PE ANO FITTINGS FOR ALL FUEL,WATERAND STEAM LrNEsAND tf eree ANo FrrrrNcs FoR tr-r- crRduttttNc otL LtNEs EXCEPTIYHEREOTHERWISE SPECIFIED.

7LL

RUN-TN OF ENGINES AFTER OVERHAUL COOLING SHROUDS A shroud or cooling cowl should be used during run-in of a geared engine to insure satisfactory cooling of the cylinders. One may also be used for direct drive engines and should be used if it is desired to run the engine with the cylinder air deflectors in place. The cooling shroud takes the place of the cowling which encircles the cylinders in a normal airplane installation. It is usually flared at the forward edge so as to deflect sufficient air over and between the cvlinders. It

should be constructed of a heavy gage durable material to withstand the constant buffeting of the test propeller and should be mounted independent of the engine so that it may be quickly moved to the front of the test stand to allow easy accessin mounting and dismounting the engine, unless it is made with hinged sections as illustrated in Fig. 70L to allow the engine to be mounted and dismounted without disturbing the shroud.

FUEL SYSTEM The lines feeding fuel to the engine should have a minimum diameter of one inch and should be free from sharp bends or restrictions of any kind. Particular care should be exercised to provide sufficient flexibility in the piping to prevent line breakage or leakage. In no case should a trench or connecting agebelow the floor be used to carry piping or controls into the engine compartment, as fuel or gasesmay collect in such a ageand cause an explosion or fire. A wobble pump with relief valve should be installed in the fuel system to facilitate filling the carburetor prior to starting the engine. A primer, either manually or electrically operated, should be connected to the primer fitting on the engine. The priming pump may be installed

either in the control room, or directly at the engine. The system should be provided with a means of measuring fuel flow for the purpose of checking consumption. The simplest method of measurement is a flowmeter calibrated for the specific gravity of the fuel used. A very satisfactory method is to weigh the fuel and accurately time the consumption of a given weight. Another method of measurement is by means of a volume gage. When a volume gageis used, it is essential to have an accurate check on the specific gravity of the fuel. A suggested fuel system is shown in the piping diagram (Fig. 704).

OIL SYSTEM The piping of the oil system should be at least Lrl in. in diameter, and as free as possible from fittings which tend to restrict the oil flow in order to insure an adequate supply of oil to the engine under all temperature conditions. Particular care in this regard should be given to the oil intake system. In order to provide a positive supply of warm oil to the engine when starting in extremely cold weather, a wobble pump capable of building up at least 60 lbs./sq. in. pressure should be incorporated in the oil intake system. Provision should be made for catching the cold oil that is in the oil intake line as hot oil forces the cold oil out before this line is connected just prior to starting the engine. The oil system should incorporate oil cleaning provisions, such as an oil fllter in the oil return line to the engine. An oil filter which has proved satisfactory in test stand operations is the Fulflo Model WFDS with 1136VC Type fiIter units manufactured by the Commercial Filters Corporation, 16 Macallen Street, Boston, Mass., U.S.A. Both the oil pipes and the filter should be so ananged that they are completely demountable for periodic cleaning. If it is not possible to

make the pipes completely demountable, they should be arranged with gpadual bends, so that they may be cleaned easily with a swab. The filter should be cleaned and new filter units installed after 300 hours of operation. The filter manufacturer's instructions for renewing the filter units should be followed. In order to maintain oil temperatures within the desired range, a combination steam and water radiator may be introduced in the oil system. Thus, by applying steam, the temperature can quickly be brought up to the desired point and by r-egulating the flow of the cooling water, it may be maintained within the desired limits. An accurate measurement of the oil consumption may be obtained by mounting the oil tank on a platform scale. Figure 704 illustrates a suggested oil system. Warnlng - It has been found that, in test where the oil is vented to the stand operation -air, there is sometimes a tendency for outside the oil to form a high acid content. This condition, if allowed to remain unchecked, can cause conosion or "washing" of the leaded master rod bearing and possible destruction of the bearing. It iv particularly important that a close

7L2

RUN.IN OF ENGINES AFTER OVERHAUL

check be kept upon the acid content of the oil. If the neutralization number, according to A.S.T.M. analysis method No. D 188-27 T, exceeds .3, there is danger of corrosion of the leaded master rod bearing. The oil should be changed any time that the neutralization number approaches this figure. It is good practice to change the oil every 30 hours and, every second oil change or every 60 hours, to flush the oil system out with clean, new engine oil. When this is done, the oil cooler should be removed and cleaned separately. Il at any time, the neutualization number of the oil at the end of the test exceeds .65, the engine should be disassembled and the master rod bearing inspected.

The use of an acid inhibitor in the test stand oil will aid in preventing high neutralization numbers and in prolonging the periods between oil drains. Thq company furnishing the oil should be consulted in this connection. The use of an oil cleaner in the oil system will also serve to prolong the periods between oil changes. Atty increase in operating time betweei oil changesshould be approache-dgridually as warranted by the general condition of the oil and its freedom from excessiveacidity. If there has been an engine failure on the test stand the complete oil system should be flushed out with a petroleum solvent.

CONTROLS Engine controls are provided by suitable bell cranks and torque tubes which extend from the engine mount assembly to the operating room. Hydraulically operated controls are being used, in some instances, with very satisfactory results. It is recommended that the streamlined member which houses the operating controls, fuel lines, oil lines, and instrument wires extend from the side of the engine mount drum to the wall of the test house on a level with the horizontal center line of the ing drum. INSTALLATION

This streamlined member should be ed from the wall of the engine room and should be connected to the suppoiting drum by a flexible leather section. Fle}ible connections should be provided at this point in the fuel lines, oil-liJres, "Fuel ind engine controls. As stated under plt underneath System'i, the use of a trench or -In case of an-y tie engine is not recommended. leakage or breakage of the fuel line,_fuel will collect in such a trench and any explosion or fire will be conducted directly to the control room.

OF ENGINE FOR TEST

The test stand should be equipped with an Engine Mounting Ring, such as Pratt & Whitney Airbraft Part No. TC-5t259,. as illustrated in Fig. 702. The starter which is to be used should have its gasket and be installed on the engine. proper -It shoutii be securely fastened and the attaching nuts safety-wired to prevent it from becoming loose during run-in. The fuel pump with its proper gasket should be installed on the engine with the fittings necessary for the connection of the fuel lines. Lifting Sling PWA-37, in conjunction with a hoist, should be used for lifting the engine into position for mounting on the stand. Geared ilrive enginesshould have an additional rope slilg to the "nose". This rope sling should be attached to the hook of the chain fall and ed around under the propeller shaft to keep the center line of the engine horizontal while installing the engine on the test stand. The engine should be secured to the Engine Mounting Ring with nine bolts. The following instrument and control connections should be made: 1. Connect manometer line to blower rim for measuring manifold pressure (absolute blower rim pressure to be used as manifold pressure in determining horsepower).

2.

Connect manorneter line to No. 1 inlet port, also for measuring manifold pressure. (Optional)

3.

Connect the tachometer.

4.

Connect the throttle control.

5.

Connect the mixture control. Connect main oil pressure gage line to the connection at the upper left side of the rear section. Install propeller governor cover Part No. 26646 on Wasp and Hornet engines having provision for such on the nose section.

6.

7.

Connect pressure gageline to oil agein "nose" section. Thfu connection is located to the right of the governor mounting -Pgd' as viewed from the front of direct drive Wasp engines. On geared Hornet engines the cbnndction is made at the boss on top of the reduction gear housing. 9. Connect manual control to the two-position propeller control valve for engines so equipped. 10. Connect fuel line to the engine fuel pump and to the carburetor. 11. Connect fuel relief valve (if not integral with fuel pump) in fuel inlet line to carburetor. 8.

NOTE:-(FFON RIGHTSIDEOFENONEAND (Q= ONLEF' SIDEOF ENGINET FROMFEAR. LOOKING SPEEDOFSHAFTSREFER TO CRANXSHAFT SPEED A - C A R B U R E T O RM O U N T I N G P A D -SHAFTSPEED ITOI S T A R T E R I T O U N T I N GP A D - sHAFr seeeo ti ro t c- GENERAToR ircuNTtNG pAD - SHAFTSPEED ITO I (L) O-FUEL PUMP MOIJNTING PAD - SHAFT SPEED ITOI (ReL) E -VERTICAL A,XILIARY ACCESSOFI. MOUNTING PAD (L&R) F-TrcH DRtvE-snerrseeeofrot

B-

c -orL rANK vENr ro eNo. - txtaru.er (REL) (l) eRESSURE cAGe coruN.-$xzzr'rRr H-otL

(oprroNAl

NECESSI OF BREA

LocATtoNs)

I _ OIL PRESSURE RELIEF VALVE (R) J -ENGINE OIL SUMP DRAIN I-I8N.S-3

477 7

K-OIL PWP L-

o t L T N L E T p A D ( A V A T L A B L EB y R E M o v A L o F o r t -

M - OIL OUTLET PAD N-orl ourLET THERMo. coNru.-|xrerur-r

INLETaTHERMo

c o r . r r u .e s s V . ) 4.777

(d

FRONT -i.IOSE COWL P- REAR - NOSE COWL

O

tpol .562 !

Q-FRONT - RING COWL R- pRop sHAFT pLUG(HIGH pREss. otlreeo) ST-

a4

IGNITION WIRE MANIFOLD puMP iiouNTlNG FLANGE-SMFT

SPEED trrot(L)

vAcuuM

U - MAGIIETO BOOSTER CONN. ONE MAGNETO ONLY v-I\,IAGNEIO GROTJNDCONN. BOTH MAGNETOS W-HYDRO

ADJ. PROPCONTROL LEVER

x-BREATHER-f,rosr y-

conn.(il

@) -n7so(o?o)

MANTFOLC PRESSURE CeCe CONr.r.-$x27N.p.T (A.al)

Z-L;FT;NG

DRILLED oFEN|NG lS REQIJIRED lN THE COIvPANION FITTING

LTNKS

LE,\GTH Of, '

A-A-LOCATION TO BE USED WHEN PROVIDING OIL TO PROP GOV (HaururoN srD. pRoP To Ft-RNtsH sPEclAL PLUG WHEN USING THIS LOCATIONJ

REAR FACE LINE OF MOUNTING LUGS

B-B-REMOVE INNER PLUG UhDER SQ. HD PIPE PLUG WHEN DESIRINGoIL PRESSURETO PAD-ETR.-l.)

+L ft. a

c-c-AccEssoR/ou nerunr+-txtINpr BLASTTUBEcoxu. |-t+ H.e.r (nal) D-D-MAGNETo -t-ra ru.r-s coNNEcrroN E-E-orLrNLET TI-ERMoMETER F-F-OIL

.-sg FRONT FACEOF THRUST NUT

INLET FLANGE

t' Z 3 !2

fix aaxr-r

GG-ROCKER BOX OIL SUMPDRAIN I-I8N.93

4-5TU6

+d

txeaN.r-a 6.STUDS

f x rarvc-:- ljoeee

J"'

FRONT VIEW OF THRUST CO/ER STUDS

ill?."-rH,s sr

NOSE COWL FRONT UEW

. cstzE

t.001 .250 D.HO

TORQUE LIMITATIONS ON ACCESSORYDRIVES- D-2695O

zjf on *3o SHAFT END PROPELLER ROTATES COUNTER CLOCKWISE WHEN VIEWED FROM FRONT

DEFIICTOR ASS/. COMPLETE-}.486I0

ENLAR@ VIEW OF SPl SCAE 4'

(rRessunervpd

MfN. ll Mrt. -L

FOR PRIMII{GSYSTEM SEE DRWG, C-45936 EXAMINE FOR CLEARArcE RocKER Box coNTouR on'wb

r

"it

jurr.r *st(.ooz)

+zttg

EQUIPMENT INCLUDED IN C.G LOCATION MAGNETOSOIL PUMP TACH DRIVE IGNITION WIRE CARBURATC'R

r_ !oo.

CHORDAL .0672 SLOTWTDTH.0652

l:886to. ----f -

4t7

4583 PD.

II TEETH 24146PtTCH so'pRessuee

t_

see (r4os) LL pRE ont OIL FEEDLOCA -

4.777 THE INVOLUTE TOOTH FORM SHALL BE TRUE INSIDE THIS DIAMETER.

l l

R. APPROX.

ENLARGED VIEW OF SPLINES SCALE 4: I

fnor.rio*^r"^r.

f, za Nr4- STU

,lz+-M-s '- 4-STUDS

nro.I-raxs e.oe-sartffif

;**6o*'r. I]A DR'LLJ I rq.E'ssuRE ott.:ED LOCATION

tooo r t.625 DrA.

raocra)ontu.

tdro22

c'stNKeo'4$on*i

^ ls': -,.eI ,-.i33 6 oi,i,i\6$---_"'-ill"

Dr& TACH DRIVE FULL SIZE

- an'* ! _:-

.3/r4_+i+*J

cn n.uax$_.azslffi

ua.

t oo5

t

-jza ":-* DEVELOPMENT OF JAW

$ onrul

[.<,-- :r 5t-iNEs';'ffi'-toot'$$!orl ,, vrA_.zrg$L - ? / 'c I

-.aa

61 -t:]:-{-=

/ / l FRONT,SUPPgRT- RrNG COWL / /FULLSIZE

3HOLES 3o' +f l'41/, 1-1/r/

/ 3oif.9Y!'"*." ;l{5 ro FAcEoF GEAR

@ Sxas

c

COWL LUGS WILL BE IN

LocArroN sHowNwrrxrrc$

EXHAIJST PIPE FLANGE

GEi\ERATOR DRIVE

T2JAWSEQUALLY SPACED

j srze

sceleI sze

I

I//

/Qor

,rit

srARrER

D€ t r H l :': :l t. t \ I J _. al

ANGULAR LOCATION OF TH]S FLAhIGE TO BE DETERMINED AT Ei{GINE INSTALLATION, REQUIRED FOR REi'Or'ING OIL PUMP BODY

RUE ANGLE OF FLANGE tf- a4-

I

fixz+r.r.n-s 2- STUDS

-F E|t x: Ar€. EASa

OILOUTLET PAD FULL SIZE S :r^CE FOft l2 TEETH ?O/ag PIICA :'r- STRA|NEFI S O . P R E S S U E EA N G L E gOF S:\

.ozarl.333

MOUNTING LUGS DRILLED HOLES EQTJALLYSPACED

smi333ore

o25R.

D€VELOPMENT OF JAW

alf r,lrxc.on. ovER RocKERco/ERs ftf corvl cLEARAT€EDrA.ovER ROCKER@VER STIJOS

APPROX

ll t6

frur.t

TNVoLUTE roorH i FORMMUSTBE TRUEINSIDE THISDIA.

*MAX

[; I

5i8-t_

In ttt--?

__-t riio.

DRILL DIA. 2 HOLES

F-F R.6Z

Joos r.875

+ooa _ooo r.500 DrA

rlvrN

+

s

frrlj

r[i

OIL INLET FLANGE FULL SIZE

VrcUUMPUMPPAD

(ruu-sze)

Fig. 705 -

Typical Installation Drawing -

v o*,aa=H

$ ora.

CARBURETOf OIL INLET PAD FULL SIZE

Wasp Jr. 83

713

!.o02 HEX 3t2

n, .8Put : x]

.3I4 DIA. MAX

07 i

HEX

fi- rar.r-r

EXTERNALSPLINE OPTIONAL

n

- lO'* - -

too5 -.2t6

-._^__Cl,-izn ;-:T.'-:P\|sNT

.osslSP' +se1.!l!

OF'JAW

f-ea Nr-a

2 )^5 i:,- - -Y 5,4:::

'-$x zaur-s STARTER DRIVE I2 JAW (oerroNeu) FI.I.L SZE -.-----PRO.JECTION

6-STUDS EQUALLY SPACED

VERTICAL AUXILIARY A C C E S S O R YD R I V E S FULL SIZE

TCABLE TO EACH

\ smnx eluc

OF THESE TWO S

7l\,-tr1\

!

\l

= \ l

= I 3f f.\frtA

--::

..--

'/ {i,

#s

t.oos sDtA.

-ed-

]xea H.r-a

B/ STARTER DRIVE 3 JAW (FULL srzE)

)€dI-OPMENT

S FRONT MANIFOLD

1 6-STUDS ! EQUALLY SPACED

RADIO SHIELDING (nena vnw)

OF JAIY

-

6t-

-r$-

l*Htr,.

Hr+

tlv

t ore ontu-

fr x24NF-3

CARBURETOR

I/PI}.ITING

PAO

FORREFEREilCE ONIY

torg,-(Rl,or.| $Gxt llDE OFEr{G.AfiO(L}'Ofi LEFT SID€OFEilG,LOOXIi'GFFOI' REAR SP€ED REFIR?O CRANK3HAFT SHAFTSPEEDS A- CARS.IRETOR NA-YgH PAD-SMFT SPEED I TOI B- STARTER iDul{Tlt\G tl ro r c- cEr€RAToR rrouNTtNG pAD-g{AFr'speeo pAD_SHAFT pur/p SpEED trO r (r_) D_ nf,L rbUNTttC pAD-grAFT E: cUN Syr{cHRONtZER SPEED tTOt (Ra.L) - sHAFr seeeo j To | (RlL j-rexs-r F- TAcl-torrETER DRIvEzusHED ro

G- orL TANK lol? ro exc- !-u-Ner H- o|L [email protected] i-27N.PT I - OIL PRESS.RELIEF \ALVE (R} I?NF.3 J - O I L S I J M PO R A I N _ h ' K- o|L PUMP (R) L- FLEL pREss. cAGE coNN. i-az

t-ta-Ner

SPACE REODE REIn/IIG FA

(nal)

(L)

st---------i EI{-ARGEO VEW OF SPI-INES SCALE.4:l

(r- )

ner

N_ oL f{-ET BAD_(R) O- OIL OUTLET BAD P - FRONT - NOSE @WL O- REAR -ISSE COWL

fixze}f-s

4 TNSERTS

R- FrcNT -RING COWL s- o€FLEcroR RtNc supPoRr lrNrerc T-

GNITON WIRE MANIFOLD

u:

BReATHERllpsEcoNN.

fi aee

ponrl

t375'toor o

lRl

SPEEDU44TO I @VER},IOR I,|OI'NTIiIG PAD-SHAFT speeo r* ro r srlrr w_ vAc. puMp lvouN?p.lc pAD_(L) (R. r. D x - MANtFoLo pREsstJRE cece conn. {-zz-N.er y- DEFLESIoR Rtlrc SUPR RT (ExHAJsr pcrtT) V-

z- FUEL rNLEr coNN. i- ta-Net

I

/r )

!0ro

LrErrs

O }|oLE IGH PRESS{JRE OIL SUPPLY TO PROP

fh"

B8-RE[,|O/E lNf€R PLTJG UND€R SA. FO. PIPE PLUG wl-€N D€SIRIhIGOIT. PREsS. TO FAD E.R.U-) C.C LFTING LINK D-O MAGNETO BOOS.1€R CONN. ONE MAGNETO ONLY F-F I|AGI.|ETO GROUND CONN. rcTH [,l,AG1'lETOs G,€ PROP. SI{AFT R-IJG GIIGI-IPRESS. OIL FEED) COr.rN. f -ra Uer H-H{CCESSORYO|LRETURT.T

REAR FACEOF tOLr{TNG

G-GROOVES EOUALLY SPrc!

-42{fAfl x2aNF-3 4 STUDS1

?-

a

(u) FRO.IT FrcE OF THRUST T{JT

EQUIPI,ENT INCLUDEDlN C.G LOCATIONS MAGT€TO5 TGNITION WIRES OIL PUMP TACFI. DRIVE €TRBURETOR

ON ALL INLET }ORNS

OF IN.PORT

\Y)t-L_ ':I{r'7 -Tv r 3 4/

z{o' TI-IIS A'{GLE Pl-AtE

S N

/

loos-

€€x3r a0

L.*r'o

:386,

OF TUBE

en€ssun€ wPq) D€FfJcToR AssY co[rPlJTE->41726 FOR PERMISSB.E TORQ{JE LOADS ON ACCESSORY DRIVES SEE D'26950 R/OCKERBOX COTITOJRSAI|D ARMNGEMENT FOR COII/LITIG R.27TI8

i---.--c L't,-E

r

3.53r tooS

2565 ' - tFoc[t

t3.531

2.565 1.loos

lpos

I

zsoa!.o,\

fx2a NF-3 12 STLDS

- | x a+ r.rr- a---1 r e 6 sruDs FRONT VIEW OF TNUST CO/ER STI.DS fx

r ON C - 3 - = r

ffitrr-

t

FROIIT VEIVOF STuDS FOR CC'IA'LINGSLPPOR'T CARB DN

F.F

GROUND

.t

I t6

I

REAR MANIFOLD

t7' rE

.l

r--_ 4.777'

. i Gorcot*s..

--r-

tt

Tt5 rl l u _ I --1i-err

&sTr.at

RADIO SHIELDIiIG (nern vrew,)

Fig. 7054

ffifi.'i'tr-3[sr * \H,4 hl

PRO,'ECTPN OF T}EE

u4--t

;SPACE REa,D.FoR **,* *f^(ERs

ottY

/

/

J

---rS'

,

-E

-I

ir

{rac nr-r 4 STT.DS

;i-

ILARGED VIEW oF sPt-h€s

s JAwsJ EpUALLY SPACED

!.oro 1@ " .52o 4

i|rel xr-s

l---.i-

- {tr--

9 STr.rOSPRO-ECThIG S FROM PADFACE.

**,*/

6!n Elru

SARTER DRilE 3-J.il Fllr lrzE

t oF cYLrNo€R,

\',

F-venncer_ e\

r8tr

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I 4 4 STUDS sruDsI

I

/ ,/

/

i. Lax.

t

.675::tglor^

,-.-.

@ L3252 0 +oo2 _,OOO5

FULL SIZE

tdLEiIGTH OF E spt rNr

--r -l . xx24NF-3 24ilr'

-----t4il

I

.?@'DtA.

6-GROOVES EQUALLY SPACID

TO FACEOFGEAR

o

hr

.OF UT€R

\..

ry"

f,xea}f-r 2-STiDS

NOR DRIVE

sc r/E i srzE

r"n

SECTPN THRU EXHAUST PORT FULL SIZE

OI.(I,TfT nltrll

-firaar,rF-3

PAD

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2-STUOS

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I

9I\DUNTII{G LUGS

Li I ll

$'oeruuo xoues

, u l t 6iri l "

EQIALLY SPACED

EI.IG.DIA c^/ER ROCKERCCI\/ERS, i, D-CO/VL CLEARAI.ICE DlA, c^/ER tft ROCKER CO/ER STUDS.

-*2fe

n(nss)ue. r CARB FTTOT'

NA}€E SPACEREqJIRED FOR REIYOVINGOIL PUMP BODY

.*

t-o 2-

ROO Tt8E5

ro.DrA.

+-_-+r, .r+l83lneer.aPnEssrJRE

@:*

8t

OIL FEED I-oC,TPN

i i

"FT - q i

.soo'.*9!

I

af1

CARB. BOTTOM FLAI€E

Fig. 705^{ -

Typical Installation Drawing -

Wasp S3H1

TACH.F r,E RI-L

J:ZE

7L4

iEN

F^CE OF

sTr.Dsoil-Y OUANTER gZE

FRO{T i'P]FOflT-FT€@TL ru,! t(!E

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- $Clgc

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-'+tS ._T

F3 SURTER DFIE 3-Jfl Flrr |IZE

|ter xr-r

9 STIJOS FRO..ECT|NG T FRC'M PADFACE.

c. f

CYLTND€RS --------\

X

t .ili lsi l

EXHAUST STACX TO BE SLDE FTT IN LII€R

lo

fr2erf-r

f

n-Âi,

,-{lrzarc-3 9 STI,DSPRO.ECTING i FMt|

PAD FACE.

SECTPN TI{RU €XHAUST PORT FULLSIZE

{."L -rtZ---

. f : q"--

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--

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2-STTJOS

35'

---r

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gs'

OIL IIILET PAD F1JLL3ZI

9]'DUNT|I{G LUGS

fi'oRtueo noues EQTALLY SPACED

DLE CUTOFF-PRIi/ER

D.-ET.IG,D|A Or'ER ROCKERCC^/ERS. D-CO/VL CLEARArcE DIA,O/ER

;*

RocKERco/ER sruDs.

Z\\/r------€PEN

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CARzuRETOR @NTROLS

SPACEREOUIREDFOR RElvOl/ll{G OIL PUMP SODY !R.ET

D

:*

TL€ES

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\\'asp S3H1

7o',.

JZ'"'",'"

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l r-&#llgtg'^. *-'3!L

@:

rAcH.m € _

Rrl-g|zE

FORREFEREilCE Ol{tY

7t5

RUN.IN OF ENGINES AFTER OVEREAUL *Note-A

t2.

Connect fuel pump drain line.

13.

Connect a tee into the blower rim manifold pressiure line and lead to the economizer unit of the NA-Y9J carburetor (used on someWasp engines).

L4. Connect a mercury manometer to NA-Y9C, NA-Y9G or NA-Y9G1 carburetors to indicate the absolute pressure below the carand buretor when the automatic mixture power control unit is checked in "Mid" and ('Cruising" position. This connection is made at the carburetor on the accelerating pump side near the parting section and automatic mixture regulator flange. 15.

Connect a line from the automatic mixture and power control unit of NA-Y9C, NAYgG or NA-Y9G1 carburetors to a tee in the main oil pressure line.

16.

Connect a line to the oil drain connection of the automatic unit of NA-Y9C, NAYgG or NA-Y9G1 carburetors and lead this to the oil drain pipe on the left side of the engine rear section.

17.

Connect breather lines to the breather connections of the engine.

18.

Connect priming system.

19.

Connect fuel pressure gage line to carburetor.

20.

Connect magneto ground wires.

2L.* Connect head thermocouples to at least two cylinders. 22.

Install carburetor air inlet duct.

23.

Connect air inlet thermometer line in air duct to carburetor.

24.

Connect oil inlet and outlet lines.

25.

Install exhaust stacks.

26.

Install cooling cowl (if used).

survey of all cylinder hgad and banel tdmperatures should be made on the first engine run in a new test house, or on the first engine of each type to be run in an old test house. Tliese temperatures should be determined by spark plug gasket thermocouples ior- head temperatures -and rivet type thermocouples embedded just ab6ve the cylindef barrel mounting flange for banel temperatures. Frbm tliis temperature survey, the two hottest cylinder locations can be determined ahd thermocouples used at these locations for all future tests. Cylinder barrel temperatwe measurement is unnecessary after the initial check.

The installation diagram, Fig. 705, *.itt be helpful in finding the previously mentioned connections. The test propeller should be inspected prior to installatiott'ott'the engine propell-er shaft to be sure that its hub splines and nut are free from burrs or dirt which might cause damage to- the engine propeller shaff. The propeller shaft snSUa bêc6vered with a light o-il, the propeller installed and the attaching nut securely tightened. Any loosenesswill allow the test club to work on the propeller shaft which may cause damage or galling. For the tightening gperat-ion a torlue of from 625 ft.-lbs. to 750 ft.-lbs. should be applied to the propelle,r nut. Thit may be accorirplished bv urling a bar fogl feet lon! and applying a weight of-between 160 and 190-pound; ai the end ol the bar. The weight should be applied at right angles to the ground. The bar shorild not be struck with a hammer or other heavy instrument except to check the tlghtness of thd nut. To check-the tightness of the nut after the above operation has been performed, a 21h lb. hammel may be used to strike the bar near the nut. Care should be taken not to exceeda normal swing of the hammer.

TEST PROCEDURE GENERAL An experienced test operator should have charge of the run-in of an overhauled engine. The operator should keep the engine and instruments under constant observation. A log of the engine test (seesample sheet, FiS. 706) recording observations at 15 minute intervals, should be kept filed with the engine inspection and overhaul records at the completion of the test. It is recommended that the temperature of the air entering the carburetor be maintained at 90" F. (32" C.) for test stand operation. This is particularly important when running-in engines equipped with NA-Y9C, NA-Y9G or NAYgGl carburetors.

The engine should be watched for oil and fuel leaks, and=necessary corrections should be made during the run-in, where possible. A few minor adjuslments, 6uch as oil and fuel pressure relief adjustments, are usually necessary-andshould be made during th€ run-in. Where the engine is equipped with short exhaust stacks and it is possible to watch the exhaust flame from each cylinder, the flames should be watched for any difference or change in color which might indicate misfiring plugs, excessively lean or rich mixtures or other discrepancies at one or more cylinders.

7L6

RUN.IN OF ENGINES AFTER OVERHAUL NO'

SERIES-NO.-SHEET

ENGINE

OBSERVED

BY

LOG OF ENGINE TEST sTD. OBS. BAROMETER-IN.

CARBURETOR

HG. AT-

F.

TIME

HUMIDITY-FUEL

DATA

CARBURETOR

MAGNETO

TYPE

LOSS OF REV'S.-RIGHT

NO.

RIGHT NO,-LEFT

MAGNETO

LEFT MAGNETO

TEST CLUB

REMARKS

Fig. 706 -

Sample Log of Engine Test

(OCTANE RATING)-

7t7

RUN.IN

OF ENGINES AFTER OVERHAUL STARTING

THE ENGINE

Before starting the engine, a wobble pump in the oil system should be operated until the engine pump is supplied with oil. This precaution is particularly important in cold weather. Where it is extremely cold, the oil feed line should be disconnected at the engine oil pump and the cold oil forced out of the line through use of the wobble pump just prior to starting the engine. Instructions for starting the engine are contained in the Operators Handbook.

tenths inches of mercury), below the carburetor in the "Mid" and "Cruising" positions with the throttle wide open. If the unit will not maintain the desired regulated pressures within the aforementioned limits, it is not functioning properly. If the unit has been overhauled and bench tested as described in Chapter XVII, only in rare caseswill it require readjustment and this should be done only by someone who is familiar with the proper procedure.

These instructions should be strictly adhered to. Oll Pressure - If the oil pressure, after starting, does not on the gage almost immediately the engine should be stopped and an investigation made for the cause.

To check the automatic mixture control unit while installed on the engine, the following procedure should be carried out: 1. With the throttle partly closed, (1200 R.P.M.) put the selector valve in the t(Mid" position and speed up the engine by opening the throttle until the manometer indicating pressure below the carburetor reaches a point where there is no change in pressure for an increase in throttle opening. This will be the pressure to which the automatic unit is regulating and it should remain constant for all throttle positions from this point to full throttle. If the operation is satisfactory and the pressure is correct for the particu"Cruising" lar carburetor setting, the position should be checked. 2. To checkl the "Cruising" position, partly close the throttle and move the selector valve to the "Cruising" position; then throtspeed up the engine by opening the "Mid" tle, as was done in checking the position. The manometer indicating pressure below the carburetor should show an increase in pressure until it indicates the regulating pressure for the "Cruising" position, anil should remain constant for ah throttle positions from this point to full throttle.

Before the run-in is completed, the pressure should be set, by adjusting the relief valve so that it is 70 - 90 lhs./sq. in. (5 - 6 kg./sq. cm.) with the engine turning 2200 R.P.M. and the oil inlet temperature at 140" - 167' F. (60' 75'C.). Fuel Pressure - If the fuel pressure is not within the desired range of 3 - 5 lbs./sq. in. (0.21-0.35 kg./sq. cm.) at 1000 R.P.M. and above, it should be adjusted by means of the fuel pressure relief valve. Englne Run-In Schedule - The following schedule outlines the minimum run-in period recommended for properly seating piston rings and burnishing newly installed bushings, etc., in an overhauled engine.

R.P.M. 800-1000 L200 1400 1600 1800 1900 2000 2L00 Rated Speed

Minutes 15 t20 60 60 60 60 60 30 15

Checklng Operatlon of Carburetors havlng Pratt & Whltney Autornatlc Mlxture and Power Control Untt - This unit should be overhauled and bench tested as described in After the overhauled engine Chapter XVII. has been run-in, it is advisable to check the operation of the unit when mounted on the carburetor and controlling its operation. It is also desirable to check approximate fuel consumption in the two automatic positions. The principal check of the unit is for its ability to maintain constant, without hunting, the desired absolute pressure, plus or minus .2 in. Hg (two-

pressure below the carburetor, Note-The when in "Mid" or "Cruising" position is controlled by the air shutters; therefore a thorough investigation of the shutters and their linkage should be made before readjusting the regulator unit. 3.

The throttle should be partly closed, until it is positively controlling the engine speed and power, before moving the selector valve out of the "Cruising" position and into the "Mid" position. The throttle should be still further closed, until it is again controlling the engine speed and power before moving the selector valve out of the "Mid" position and into the "Manual Full Rich" position or "Emergency" position. The engine should be

7L8

RUN.IN

OF ENGINES AFTER OVERHAUL

Fig. 707 -

Psychrometric Vapor Pressure Chart

7L9

RUN-IN OF ENGINES AFTER OVEREAUL operated in the "Manual Full Rich" position at all times on the test stand except when checking the operation of the Automatic Mixture and Power Control Unit and for fuel consumption checks.

The carburetor is of the fixed jet type, the proper jet sizes having been determined and tested in each carburetor. Under no circumstances should these be changed without first consulting the factory.

EORSEPOWER DETERMINATION A reasonably accurate determination of the horsepower dei'eloped by a Wasp Jr., Wasp or Hornet engine may be made by ieferring to the sea level calibration curve for the particular engine (assuming that the test stand is located approximately at sea level). The Operators Handbook describes, in detail, how to use the calibration or operating curves, including information pertaining to the carburetor air tem, perature correction. If the test stand is situated appreciably above sea level, the altitude part of the calibration curve should be used as described in the Operators Handbook. The information which follows is furnished in the event that, for some reason, the closest possible determination of actual horsepower on the test stand is desired. Absolute Blower Rtrn Pressure or absolute manifold pressure (in. of Hg) is the algebraic sum of Observed Blower Rim Pressure and Corrected Barometric Pressure. Thus if an engine is operating with a Blower Rim Pressure of -2.3 in. Hg and Corrected Barometer is found to be 29.22 in. Hg then the Absolute Blower Rim Pressure (absolute manifold pressure) is 29.22 * (-2.3) : 26.92in. Hg. Corrected Barometer is found by subtracting from the True Barometer the vapor pressure (i.e. pressure due to moisture content) in the air. For example: assume wet and dry bulb temperatures of 78' F. and 84' F. resp,ectivelyQ8/84. From the Psychrometric Vapor Pressure Chart a correction factor of 0.9 is found for these temperatures. Thus, if the True Barometer is 30.L2, the Corrected Barometer is 30.12 - 0.9 : 29.22 in. Hg. Trre Barorneter is computed from the Observed Barometer by correcting the latter for temperature variation away from the standard temperature upon which the barometer scale is based. Thus if the Observed Barometer is

30.25 in. Hg at 79" F., refer to the Barometric Temperature Correction Chart, supplied with the barometer by the manufacturer, and for 30.0 in. Hg and 78"'F. find a correction factor of -.13. The True Barometer is found by adding the correction factor (with the conect sign) thus: 30.25 - .13 nn True Barometer The True Barometer should be computed and recorded once every hour. Wet and. Dry Bulb Temperatures are required in order to compute the vapor pressure from the Psychrometric Vapor Pressure Chart (Fig. 707) and obtain the Corrected Barometer. Readings should be recorded once every hour. After the absolute manifold pressure has been derived and used with the engine R.P.M. to read hors,epower on the calibration curve, the horsepower read from the curve must be conected for the variation from 60' F. (standard temperature at sea level). The following formula can then be used to deterrhine the actual horsepower: Actual Horsepow€r: Horsepower Read on Curve For example, consider the Wasp engine running at 2200R.P.M. with an absolute blower rim pressure of 32.5 in. Hg and a carburetor air temperature of 80" F. At 32.5 in. Hg and 2200 R.P.M., the sea level calibration curve shows 525 brake horsepower. Using the horsepower correction factor table which follows, a correction factor of 1.019 is found for the carburetor air temperature of 80' F. Using the correction factor in the above formula for actual horsepower, 525 : 515 actual horsepower. 1.019 The following table of correction factors for carburetor air temperatures should be used with the foregoing formula.

720

RUN.IN OF ENGINES AFTER OVEREAUL H. P. CORRECTION FACTORS Barometer 29.02 ln. Mercury

Air Temp. oF.

Correctlon Factor

Air Temp. oF.

Air Temp. oF.

Correctlon Factor

95. 96... 97... 98.. . 99... 100.. 101. L02.. 103.. 104.. 105.. 106.. t07.. 108.. 109.. 110. 111. Ltz. . 113. Lt4. .

8 1 ..

Cheeklng FueI Flow - After the engine has been run--in, the gross fuel consumption in pounds or gallons per hour should be checked. it is recomirended ihat the fuel consumption be measured at several points within the cruising range and at rated power and speedof the engine. The gross fuel consumption may be determined readily at all times if a fuel flow meter accurately calibrlted for the specific gravity of the fuel is installed in the fuel line tb the engine. Flow meters of this type should be calibrated once every two months and should be accurate to within L/6 tlvoughout its usable range. It-ryuy also be found bf timing a given weight- of fuel that the engine- consumes from a weigb! t-ank mourrted on a scale. A third method of finding the gross fuel consumption is by timingâ -given volume of fuel consumed. The volume fuel flow tank should be accurately calibrated for the specific gravity of fuel. See Tig. 794,for the various arrangements for determining fuel flow. When determining gross fuel consumption !V the volume or weifhl method, the longe,r the duration of the check, the more accurate the result will be. However, in any case, the time interval should not be less than one minute (60 seconds). flow (lbs./hr.) is computed Fuel Flow-Fuel by means of the formula: x 3600 Flow _lbs. sec. Thus if it takes74.5 secondsto empty 9 lbs. of gas out of the weight tank, the Fuel Flow : 9_. J600 74.5

Correctlon Factor

.1.033 .1.034 .L.035 .1.036 .1.037 . 1.038 . .1.039 .:.....1.040 . .1.041 . .L.042 ..L.043 . .1.044 ..L.045 . .1.046 . .L.047 . .L.047 .1.048 . .1.049 .1.050 1.051

or 434lbs./hr. In caseof stands equipped with a fuel flowmeter the flow in tbs. /hr. is read direct. (lbs-/8.P./!t.) Speclffc Fuel Consunptlon j Stto,rtd it be desired to-determine Specific Fuel Consumption (not considered practical in average horsepower, case on held test stahds) the actual"Horsepower arrived at as described under Determination", must be used. The following formula may then be emploYed:

, : Fuel m Flow (lbs.ihr.)

S.F.C,

Thus for an ensine developine 525 H.P. with a fuel flow of 350-lbs.1hr., the Specific Fuel Consumption is equal to: -350 : 525

.666lbs. lH,.P.llv.

Note-Becalrse of the several engine models and numerous carburetor settings involved, it is not feasible to cover actual fuel consumption figures in this manual. Where fuef consumPtion figures are desired for a particular englr-le model and carburetor setting, information will be furnished by the-Pratt & Whitney Aircraft Service Department upon request. Checklng Otl Consumptlon - qg+ng. .th" should be deterrun-in, th6 goss oil consumption -running the hour at mined' while the engine is 2000 R.P.M. The consumption may b-e ascertained by subtracting the weight of oil- at the ettd of tlie hour, as in-dicated on the weight tank

72L

RUN-IN OF ENGINES AFTER OVERHAUL scales, from the weight at the beginning of the hour. Readings should be recorded every 15 minutes. If the gross oil consumption is not more than 4.5 lbs. for Wasp Jr.,6lbs. for Wasp, or 7.25 lbs. for Hornet engines, and not increasing during the last two 15 minute intervals, the condition of the newly fitted piston rings should be considered satisfactory. If the oil consumption is high, or increasing during the last two 15 minute intervals, the run-in may be continued for an additional two hours at 1600 R.P.M. to further seat the piston rings, after the run at rated speed is completed. If the condition is not corrected after this run, as determined by a check run of one half hour at 2000 R.P.M., the cylinders should be removed and the condition of the rings investigated. Flnal Englne Check - Since the test club propeller does not have the same flywheel effect

as an airplane propeller, it is impractical to make a final idle adjustment of the carburetor on the test stand. However, at the completion of the run-in, the engine should be checked for idling, acceleration, and operation of the magnetos. The engine should not lose over 100 R.P.M. when opeiating on one magneto at 907o rated speed. Checks on single magnetos should be made in as short a time as practicable, as continued running on one magneto at high horsepower output can cause serious detonation. After checking one magneto, the engine should be allowed to run 5 or 10 secondson both magnetos before switching to the other alone. If the engine is to be placed in storage, it should be run at least 30 minutes at 50% normal rated speed on unleaded gasoline, before being removed from the run-in stand.

801

CHAPTER VIII

PREPARATION OF ENGINE AFTER RUN-IN GENERAL After run-in of the engine, the following treatment should be applied prior the procedure outIined for "Preparation for Installation in Ship" or "Preparation for Short or Long Time Storage". Cleanlng Englne-The engine should be washed externally with white furnace oil, varnoline, or the eqoivalent to remove all oil, grease or dirt. Care should be taken to keep the-cleaning fluid away from the electrical equipment as much as possible. Oll Dratr!_ Plugs-Remove the sump drain plug and the oil pressure strainer in the iear section. PREPARATION

Check the sump plug for signs of foreign matter. Check and clean pre$sure strainer. Spark Plugs-Remove spark plugs and check gap which should be not more than .0L5". Valve Clearances-When checking valve clearances make sure that engine is thoroughly cool. Remove rocker box covers, being careful not to damage the gaskets. Check valve clearances in accordance with instructions contained in Chapter VI. Extreme care should be taken in replacing rocker box covers as a slightly damaged gasket will cause oil leakage.

FOR INSTALLATION

Greaslng Rocker Arm Ftttlngs (Grease Lubrlcated-Wasp Jr. B Englnes)-When greasing the rockers it is advisable to turn the crankshaft so that the piston is at the top of the compqessio4 stroke of the cylinder being greased. This allows grease to reach the ball end of the push rod and the adjusting screw since neither is under pressure. At the same time the grease fittings on the exhaust rocker boxes shodd be giveq a_plentiful supply. The top five cylinders should be given half again as much grease as the lower cylinders, due to the tendency of the lubricant to drain down the push rod cover tubes. Normally inlet rocker boxes require as much grease as the exhaust rocker boxes. Checktqg Magnetos-Check magneto breaker points for condition. Make sure they are not oily. Remove any trace of oil or grbase from inside the magneto breaker housings with carbon tetrachlolide, then dry the housings thoroughly. This is important, as serious burning of the breaker points can result from a minute quantity of oil or grease,or a mixture of cleaning fl:uid anil oil or grease. Do not remove the oil from the cam oiler felt of Scintilla Magnetos. Check Cyl. Nos.-

IN AIRPLANE

synchronization between the two magnetos and if a correction is necessary,refer to Page 609. all ts Waterprooffng Magnetos-Seal where moisture might enter with melted compound Quaker Wax No. 368.* Do not put any oil, grease, or preservatlve cornpound. ln the breaker cornpartment. Checking Nuts and Screws-Inspect engine carefully and check nuts or palnuts for looseness and broken safety wire. Look for oil leaks, as such are likely to indicate loose connections, packing or nuts. Packing glands should be tightened and safetied. Give the engine a final visual inspection for any damaged parts. Cyltnder Deflectors-Refer to Chapter I for the description of the various types of deflectors which have been used on the subject engines. The following table indicates the number of the cylinder barrel-fin, counting from the top fin of the barrel, below which the butterfly clamp should be located on both types of pressure baffies (bolted type and latch type). l-2 2-B 8 - 4 4-6 5 - 6 6 - 7 7 - 8 8 - 9 9 - l

Wasp Jr. (Navy)

Fin No.

22

4

4

22

4

4

4

4

4

Wasp Jr. (Comm.)

Fin No.

4

4

4

4

4

4

4

4

4

Wasp (Navy and Comm.)

Fin No.

Hornet (Navy and Comm.) Fin No. To locate the butterfly clamp on bolted type de,flectors,install the deflectors between adjacent cylinders and locate the position of the butterfly clamp from the hole in the deflector, using the

11 11 11 11 11 11 11 11 11 8

8

8

8

8

8

8

8

8

position into which the clamp slides the most freely. Fasten the inter-cylinder deflectors to the cylinder barrels by clamps and wing nuts. Fit the primer lines through the rubber grommets

802

PREPARATION OF ENGINE AFTER RUN.IN in the deflectors and connect to the cylinders where necessary. The primer lines should be fastened to the intake pipes with clamps. For Wasp Jr. engineswhich incorporate a valve lubricator system and require installation of the cylinder oil feed pipe on No. 1 cylinder, fit the lrpper section of the oil feed pipe through the rubber grommet in No. 1 cylinder heail deflector and connect it to the inter-ear pipe on the cylinPREPARATION

The latch-type deflectors are installed in the s€rmemanner as the bolted-type with the exception that the inter-cylinder deflectors are latched to the adjacent cylinder head deflectors instead of being bolted.

OF ENGINES TOR STORAG}E

General-Unless an overhauled engine is to be placed in service within a few days after run-in, it should receive special treatment before being placed in storage. Previously, "Long or Short Time Storage Treatment" was applied to the engine, depending upon the length of time and climate conditions to which the engine would be subjected. However, since the final destination of an engine is unpredictable, it is recommended that all engines be given the maximum amount of storage protection. It is recommended, therefore, that the following treatment which is comparable to the previously recommended "Long Time Storage" be applied to all engines which are not to be used immediately after overhaul. A tag indicating the date of treatment should be attached to both the engine and the packing case. Engines to be shipped overseas should be packed in a special double thickness waterproofed packing case. Prellmlnery Treatment-During the last 30 minutes of operation previous to storage, the engine should be run on clear or unleaded gasoline. The engine should then be washed down with white furnace oil or varnoline, or their equivalent, to remove all grease and dust. When washing the engine, the cleaning spray should be kept away from all electrical equipment. Preferably while the engine is still warm, drain the engine of excessoil by removing the sump drain plugs and main oil screen and plugs. Clean and replace the screen and all plugs. Within two hours after the conclusion of the clear gasoline mn, spray corrosion preventive compound, Rust Veto No. 3568-8*, into each cylinder, with the piston at the bottom of its stroke, in sufficient quantity to insure adequate coverage.. The following procedure should be completed as soon as possible after engine shutdown, but in every case the requirements regarding Rocker Boxes and Exhaust Ports should be completed within 24 hours. Roeker Bor Covers-Remove rocker box covers.

der with a hose connection. The hose connection should be secured to the pipe with wrap locks or clamps. The lower end of the pipe should then be connected to the lubricator pump.

and clean the

Rocker Boxes-Inject sufficient corrosion preventive compound, No-Oxide EEE, * into the

rocker boxes. to coat thoroughly the valve rockers, valves, valve springs, and the interior of the rocker boxes. Actuate the valve mechanism to insure thorough coating of the valves and valve gurdes. Replace the rocker box covers. Thrust Bearlng-Remove the thrust bearing cover plate, and thoroughly coat the thrust bearing with corrosion preventive compound, NoOxide EEE *, then replace the thrust bearing cover plate. Generator and Vacuunr Punrp Drives-Remove the generator drive and vacuum pump drive cover plates and apply corrosion preventive compound, No-Oxide EEE *, to the splines and bearings. Replace the cover plates. Exhaust Ports-Spray"compound, a sufficient quantity of Rust Veto No. corrosion preventive 3568-8*, into the exhaust ports to coat thoroughly the heads of the exhaust valves. The exhaust valves should be in the full open position to insure a thorough coating. Install the exhaust port covers. Internal Englne Preservatlon-(To be completed prior to cylinder treatment). With spark plugs removed, pump corrosion preventive compound, No-Oxide EEE *, through the engine oil ages by means of the engine oil pump in sufficient quantity to^411.the system. Thit.will require some mearu of driving the propeller shaft at a speed of approximately 150-200 R.P.M. Do not allow the first oil leaving the engine oil outlet to mix with the supply which is entering the engine. Rotate and rock the engine on the stand to coat thoroughly the interior. Drain the excesscompound from the sumps. Replace the plugs and safety in place, the engine stand Cyllnder Treatment-Turn so the engine propeller shaft is extending vertically upward. Close the lower set of spark plug holes with plugs. With the intake valve open and the piston at the bottom of the stroke, spray the interior of each cylinder with corrosion preventive compound, Rust Veto No. 3568-8*, through the top set of spark plug holes, so that a quantity of spray will be deposited on the intake valves as well as on the cylinder walls. Follow-

803

PREPARATION

OF ENGINE AFTER RUN.IN

ing this operation, rotate the crankshaft at least six revolutions for piston ring coverage. Respray each cylinder with the piston at the bottom of the stroke for final cylinder wall coverage. Remove the plugs and drain the excesscompound from each cylinder by tilting and rotating the engine on the stand. After draining, install dehydrator dummy spark plugs, Protek-Plugs*, in all the spark plug openings. Attach the spark plug leads to the dehydrator plugs, and insure that the plugs are tightly seated on the spark plug bushings. Do not turn the crankshaft after thls operatlon. Note-Do not remove the moisture seals from the dehydrator plugs, until they are to be installed. Palnted Surfaces and Rubber Parts-Corrosion preventive compound, Rust Veto No. 3568B *, fu detrimental to paint and enamel. Remove any of this compound spilled or sprayed onto paint€d surfaces by wiping with a clean, dry cloth. External Englne Cleanlng-Spray the exterior of the engine with cleaning fluid (white furnace oil, or varnoline) and dry with compressed air. When spraying the engine, the cleaning spray should be kept away from all electrical equipment. Particular attention must be given to removing cleaning fluid from all rubber parts. Carburetor Openlng-Install the hot spot, if shipped with the engine. Securely attach a % pound bag of dehydrating agent, Silica-Gel*, in the intake manifold. Mount the wooden cover on the carburetor opening, using acid free waxed paper as a gasket between the cover and the carburetor mounting flange. Openlngs-Cover all other openings. Cover breathers, oil inlet and outlet connections, etc., with waxed paper securely tied in place. Propeller Shaft-The exposed surface of the propeller shaft should be coated thoroughly with corrosion preventive compound, No-Oxide EEE*. When required, a thread protector cap should be installed. care Surfaces-Special Crankcase Partlng should be taken to coat the parting surfaces on the nose and rear sections with corrosion preventive compound, No-Oxide EEE *. removing the carburetor Carburetor-After from the engine carefully drain all the gasoline. Fill the entire carburetor with corrosion preventive oil, Necton No. 50 *. Thoroughly slush the interior surfaces by rocking the carburetor, exercising care not to damage the float or needle valves. Operate the throttle pumps to empty the carburetor. Drain all excessoil and replace the plugs. Lock the throttle in the full-closed position. Check all screws and nuts, making sure they are tight and properly safetied. At-

tach the carburetor warning tag, and wrap the carburetor in a waterproof bag. Magneto-Clean the points and inspect -breaker the mechanism of the magneto. Seal the magneto with melted magneto sealing compound, Quaker Wax No. 368*. Do not put any oll, grease, or preservatlve conrporrnd ln the breaker compartment. Spark Plugs-Clean the spark plugs and adjust thefu gaps.- Coat only the threads of the-sp-ark plugs with corrosion preventive compou-nd, NoOxi-de BEE *. Wrap in acid-free waxed paper, and place in the speciialspark plug shipping box. such parts Accessorles or Auxlllarles-Inspect as generators, starters, automatiC power -control unit, etc., when furnished with the engine, for proper preparation for storage. Cover.any uncompainted-poitions with corrosion preventive pound, Rust Veto No. 3568-8 *. Pour corrosion ireventive oil, Necton No. 50*, -into the fuel b*rrp and propeller governor, and rotate to fill itt civities,- w6en suCh parts are furnished with the engine. Drain the excess oil. Coat the propeller hub parts with corrosion preventive Lompound, No-Oxide EEE*, and wrap !t- in acid-free waxed paper before packing. Likewise, wrap all the above accessoriesand auxiliaries in acid-free waxed paper before placing in the shipping case. preparation .for General Inspectton-During storage the en-gineshould be c[er:-keii thoroughly to be sure thit all nuts are tight and properly safetied. The propeller thrust bearing nut should be made [ight and all parts of the engine should be in proper adjustment ready for runmng. The entire engine should then be covered with a heavy waterprobf paper and the paper secured in place. *specifications listed in this chapter may be procured 'the the' following sources. When- procuring material to fromspecifi.cationslisted, requests should be made that the matelial'be furnished i'n accordance with latest reuision of this specification as designated by a letter suffix to the specification. Speclffcatlon Number

Source of Supply

wax No.368 Quaker 8:*nf*f,T;:"1"":;:., RustvetoNo'3568-8 ";#i"f"ftf!tblf;'". o;nuV?offiir",o,N,.., No-oxideEEE ". and Chicago, Illinois Standard OiI Co. of New Jersey Necton No. 50 Sitica-Gel m.ay be procured from the Dauison Chernical Co., Baltirnore, Md. Protek-Plugs may be procured from' Pratt & Whitney Aircraft, East Hartford, Conn. Corrosion preuentiue compound, No-Oxide EEE, should be heated to 180' F. (82' C.) before using. Rust Veto .Ay'o.3568-8, should be sprayed on surfaces with a DeVilbiss Gun, Type CL-IOL, or its equiualent, with air pressure m,aintained at 4O to 5Ol.bs.per square inch.

804

PREPARATION PREPARATION

OF ENGINE AFTER RUN.IN

OF ENGINE FOR RUNNING

AFTER STORAGE

starting an engine that has General-Before been taken out of storage, extreme care should be taken to seethat all oil has been drained from the cylinders and the intake pipes. The general precautions before starting an engine are outlined in the Operator's Handbook. These precautions should be carefully followed and, in addition, the following instructions be adhered to.

allowing any oil which may have accumulated in the lower part of the engine to drain out, as well as to drain any oil which may have collected in the lower intake pipe and which would be drawn into the cylinders when the engine is started. Turn the crankshaft at least twentyfive times by hand with the above-mentioned plugs removed and allow oil to drain thoroughly.

Remove any trace of oil or grease from inside the magneto breaker housings with carbon tetrachloride, then dry the housings thoroughly. This is important as serious burning of the breaker points can result from a minute quantity of oil or grease,or a mixture of cleaning fluid and oil or grease. Do not remove the oil from the cam oiler felt of Scintilla Magnetos.

Install the spark plugs and the oil sump plugs. When reinstalling the intake pipes, the gasket between the intake pipe and the cylinder should be in good condition and the flange should be evenly seated and pulled up snugly. Before engaging the starter, the engine should be turned over by hand at least six times.

The engine should be brought up to room temperature (60'F. minimum) and the Protek-Plugs removed from the spark plug bushings. ProtekPlugs, after removal from cylinders cannot be reused with any assurance that they will provide continued protection. Therefore, it is recommended that they be destroyed immediately after removal. Oil sump drain plugs and the lower intake pipe should also be removed, thus

The engine should be run for approximately one hour, not over 1000 R.P.M., using a grade of oil from 75 to 100 viscosity. This is followed by draining the oil and replacing with a grade recommended for service before the engine is flown. Carburetor-Before installing the carburetor on the engine, the heavy oil in the carburetor should be thoroughly washed out with gasoline.

901

CEAPTER IX INSTALLATION

AND RUN-UP

INSTALLING

OF ENGINE

IN AIRPLANE

ENGINE IN AIRPLANE

subject of installation of the enGeneral-The gine in the airplane is not strictly an overhaul function; however, this chapter covers the subject briefly to acquaint the Overhaul Shop with the final operations on the engine. Wtth Flxed Mount-After the engine has been overhauled and run-in, it is ready to be reinstalled in the airplane. Before delivery to the airplane, the engine should be thoroughly washed or sprayed with kerosene or white furnace oil to remove all dirt accumulated during test and then dried with an air blast, as described in Chapter VIII on "Preparation for Installation in Airplane". Hook the Lifting Sling to a chain hoist and the sling to the lifting links provided at the top of the engine, and then relieve the stand of the engine weight. Raise the engine to the level of the mounting ring. At least two men must be available, one to operate the chain hoist and the other to guide the engine into place. Install all eight of the bolts in the mounting ring. The mounting lugs on the airplane must be in line with the mounting lugs on the engine, so that all of the mounting bolts may be drawn up without putting a strain on the engine or the mounting ring. Be sure to draw up evenly on the bolts to assure proper alignmerrt of engine and mounting ring. of Accessorles, Ptpe ConneeInstallatlon following accessories, tlons and Controls-The and the pipe connections and controls should be connected after the engine has been installed in the airplane: Vacuum Pump. Carburetor (attach braces if provided). Starter. Generator, (if provided) with all external wire connections. Carburetor air scoop (below carburetor). Exhaust manifold and pipes. Exhaust pipes to hotspot. Tachometer cable. Thermocouple wiring. Wiring from magneto to switch (ground wire). Manifold pressure gage pipe. Fuel pump drain pipe. Fuel pump inlet and outlet pipes. Fuel pressure relief pipe.

Fuel pressure gage pipe (at left or rear side of carburetor). Carburetor fuel supply pipe (at left side of carburetor). Oil Tank vent pipe. Oil pressure gage pipe. Oil inlet temperature gage. Oil outlet pipe connection (at rear center of engine). Oil inlet pipe connection (at right side of rear section below oil pipe). Hot air control rod (on air intake). Governor control linkage. Starter energizing rod (if provided). Mixture control rods (on side of carburetor behind throttle). Throttle control rods (on side of carburetor). Battery. Any other accessories, piping or wiring which were removed at the time the engine was removed from the airplane. Wlth Rem.ovable Mount-The same instructions for cleaning the engine before delivery to the airplane apply in this case as with fixed mount. Attach Lifting Sling_and remove bolts holding engine to the stand. Raise engine to horizontal positioq and attach mount to engine, fastetting with all eight bolts on mounting flange. Be sure to draw-up all bolts evenly to assure proper alignment of engine and mount. Install carburetor and air scoop. Note-As the method of connecting up these lines varies with different installations, it is advisable to consult the "Installation Handbook" or Installation Department of Pratt and Whitney Aircraft, for further information. Guide engine and mount to plane and attach mount to fuselage structure by means of four bolts. (In some installations the mount is connected to the cell structure of the plane.) Attach all oil, fuel and control lines to their respective connections provided at the engine fue wall.

902

INSTALLATION AND RUN.UP OF ENGINE IN AIRPLANE

Flxed Pltah, Controllable' Constant Speed Propellers-Complete inand Eydromatlc structions for the installation of these propellers are given in the service manual issued by the propbller manufacturer, and this manual should be cbnsulted before installation. general Run-up of Englne ln Alrplane-The purpose of the run-up of the engine in the airplane is tb insure that the installation is functioning normally and that the engine operating characteristics are satisfactory. The duration of the run-up period should be at least thirty minutes and preferably an hour. Preaautlons-Engines Runnlng Ground equipped with pressure baffies can be severely ol:erhbated wheir running on the ground unless extreme care is exercised. The effectiveness of pressure cooling is dependent on the forward speed of the plane building up a positive pressure in front of the engine cylinders, and a negative pressure behind the cylinders thereby forcing the cooling air between the fins. When running up an engine against the blocks, the flow of air is very much reduced, so that unless the power is Iimited the cylinders will overheat. It is recommended that at least two cylinder head thermocouples be installed and that, when warming up, the temperature should not be allowed to exceed 400" F. (204" C.). The maximum R. P. M. possible within this 400o F. (204" C.) limit will vary with different installations and propellers, so that for a given airplane it is good practice to determine what limiting R. P. M. under average conditions is necessary as

an added protection against overheating. It is generally possible, however, to warm up the engine at the usual 1000 R. P. M. When opening the throttle further to check the R. P. M. and magnetos, the cylinder head temperature should not be allowed to exceed 500'tF. (260" C.) in the short burst. The cylin{er temperatures are likely to increase rapidly after ing400o F. (204" C.). Where it is found necessary to give a newly installed engine a prolonged ground run-up,- the ring cowl and int-er-cylinder bafles should be removed as an aid to cooling. After this run-up, the oil strainer should be cleaned to remove any foreign matter which might have come from the tank or pipes of the airplane. Check all installations and controls to see that everything is satisfactory. of OII Pressure Rellef ValveAdjustment -adjust the pressure turn the adjgsting screw To with a screw diiver, until the desired pressure is obtained. The valve is adjusted at the factory to give ?0-90 pounds pressure at rlted sp$ when the oil inlet tempeiature is 140oF. (60'C.). When testing an eng-ine in a new installation, the pressure should be checked and, if_necessary, adjusted to give the above-mentioned pressure. However, wh-en the relief valve is once set for a particular airplane, readjustment to care for variatiotts in pressure is irot advocated. If the pressure drops abnormally, it is recommended ttrat the cause be determined rather than that the relief valve be readjusted.

1001

CEAPTER X GUN SYNCERONIZERS DISASSEMBLY Unscrew cam follower cap and lock plunger or plug from gun'synchronizer cover, using suitable wrenches. Unscrew four cap screws which fasten zun synchronizer cover; then remove cover and ittim.- Withdraw cam-follower, cam and gear shaft, bearings and bearing retainer as a unit from housing. Remove cotter pin, nut and bolt

from cam and gear shaft. Remove retainer and upper bearing from cam and gear shaft by tapping on end of shaft with a dural drift and hammer; then remove cam follower. The bearing may be pushed out of retainer with fingers after both of these parts have been removed from shaft. Remove lower bearing.

CLEANING All parts of the gun synchronizer may be cleaned with white firrnace oil.

(Specific Gravity 38-40.)

INSPECTIOIT The following parts should be inspected visually for the various conditions as outlined:

Ball bearing as described in Chapter IV, Inspection.

Gun synchronizer housing cover for cracks, mutilations and condition of paint.

Be sure that the lock plunger is of such a width that it will fit in notch of cam follower to the desired clearance. This plunger must not be rounded at the end, as if such were the case it would not seat properly in notch of cam follower.

Cam follower, cam and gear teeth for evidence of wear. Balt bearing retainer for free fit in housing. Dowel pin hole for proper depth.

Be sure that the cam follower slides freely in its respective holes in the housing.

REPAIR ANI) ASSEMBLY Press lower ball bearing on cam and gear shaft. Fit upper ball bearing in bearing retainer and insert cam follower in hole of retainer. Press upper ball bearing on cam and gear shaft. To perform this operation it is necessary that roller and cam follower be placed between lobes of cam. Secure the ball bearings and bearing retainer on the shaft by means of the bolt, washer, nut and cotter pin. Install the cam follower, cam and gear shaft, bearings and bearing retainer in the housing as a unit. Place laminated shim over gun synchronizer cover mounting flange and housing, and fasten cover in proper position on housing with four cap screws. Insert a small screw in the tapped hole at the end of the cam follower; then pull follower to the top of the stroke. Screw lock plunger in cover insuring that it seats properly in notch of cam follower. It may be necessary to move cam follower slightly to permit engagement of plunger in notch. Care must be exercised not to jam plunger when it is installed. In the event that the plunger will not enter, it should be removed together with the cam, and the width of the notch should be checked.

If the end of the lock plunger becomesjammed, do not attempt to correct this condition by filing the burred edges on the plunger, as in so doing the plunger may become sufficiently reduced in diameter to render it a loose fit in notch. Since a loose fit will seriously affect clearance between cam and roller on cam follower, a plunger which is damaged at the end should be replaced with a new plunger. Remove inspection cover plate on housing (after lock plunger is installed) and check clearince betwebn cim and roller on cam follower. This clearance must be in accordance with that specified in the Tables of Clearances and should b-e adjusted (if necessary), by adjusting the laminated shim beneath the gun synchronizer cover to provide the proper clearance. On later synchronizers an ecc'entric sleeve on the lock plunger is used to adjust the clearance between lhe c-am follower and the cam. This should be turned until the desired clearance is obtained between the cam and cam follower. Be sure that the inspection plate is installed after clearance is checked. Remove the screw in the end of the cam fol-

1002

GUN SYNCERONIZERS jammed and cease to function or else the gun may operate on a hair trigger instead of a pull trigger. Under these conditions a slight wear on the mechanism will cause the gun to fire continuously, with the result that the operator will be unable to shut it off.

lower, and screw cam follower cap on gun synchronizer cover. Secure cap screws which fasten gun synchronizer cover with safety wire. Note-If

the gun synchronizer is not assembled as described it may become INSTALLATION

Place the proper gasket on the gun synchrotizer mounting pad at the top of the rear section. Then fasten gun synchronizer to mounting pad with the necessary washers, castellated nuts and safety.wire. Be sure that bevel gear in synchronizer is properly meshed vrith the gun control gear. If the backlash is excessive,it may be reduced to the desired limit by either lapping the base of the housing on a surface plate or by machining it off. The amount of metal to be removed will be very small, therefore only a very little metal should be removed at one time.

Fig. 1001 -

Adjusting Clearance Between Cam and Operating Plunger

If a case is encountered where the backlash is insufficient, this can be overcome by inserting a shim to match the mounting surface of the synchronizer housing. When installing a shim care should be taken to insure that the diameter of the hole in the center of the shim coincide accurately with the hole in the face of the housing, otherwise the bearing retainer for the vertical gr" drive shaft will not be held sqcurely in position. The gun synchronizer should be securely bolted down and safety wired in place. The gun synchronizer cover screws should be safety wired in place.

Fig. 1002 -

Gun Synchronizer and Operating and Locking Plungers

\--

1003

GUN SYNCERONIZERS

.ooo5L oo2 L

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OB TA IN C LE A R A N C E W ITH PLUG AGAINST THIS SURFACE

LA MIN U M S H IM W ITH H E A V Y S E C TIONN E X T TO B A LL B E A R IN G . PEEL OFF IF NECESSARYTO OBTAIN .OO2 TO .OO5 C LE A R A N C E B E TW EEN C A M A N D R OLLE R IN LOC K E D P OS ITION .

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THESE GEARS ARE CHANGE-

ABLE FOR DIFFERENT P R O P E L L E RG E A R I N G R A TI O S .

oo4 TO .OlO BACKLASH .ot4

IN HOUSING.OOO5T .oo25 T tN covER .ooo .oo2 L

Fig. 1003 -

Gun Synchronizer Clearance Chart

1101

CEAPTERXI SPARK PLUGS GENERAL Spark plugs should be inspected and tested each time they are removed from an engine. The number of hours between these inspection periods depends a great deal upon the type of operation to which the plugs are subjected, the rate of electrode gap increase usually being the determining factor. In general, operators set up inspection and reconditioning procedures to suit their individual requirements. However, it is recomCLEAIYIIIC

mended that the spark plug manufacturer be consulted as to details in connection with the particular make and model spark plug in use. The following instructions treat with the recommended procedure for servicing spark plugs in a general manner. For specific instructions and tools for the different makes and types of plugs, the respective manufacturers should be called upon.

AND INSPECTION

It ls _v_eryseldom necessary and definitely undesirable to complefsly disassemble spark plugs at every periodic inspection. Under normal conditions, such as a scheduled operation where control is rigidly maintained, the following service procedure is recommended. Spark plugs should be installed in the engine as received, and operated until the tips of-the center electrodes have been reduced toapproximately the manufacturer's specified miirimum diameter or the ground electrodes to the minimum thickness, b"!rg removed only for inspection at the prescribed periods and serviced as outlined in this section. Before installing the plugs, a light coat of mica lubricant should be applied to the threads, and before screwing the plug into the cylinder, inspect the spark plug bushing threqds to make sure they are absolutely clean. Use fully annealed solid copper gaskets that are in good condition. Do not use old gaskets which have becomehard, distorted, or burred from previous service. Care is to be exercised in preventing excssive force being used when tightening the plugs in the cylinder. The pressure exerted should not exceed 450 inch pounds when cold, (approximately 37 foot pounds). Spark plugs are to be removed from the engines at the prescribed inspection periods at which time they are to receive the following maintenance wlthout belng dlsassembled. Lightly brush the threads and end of the shell using a soft wire brush. Do not use excessive pressure as it will tend to round offthe electrodes. Inspect shell threads for nicks and burrs. Chase vyith 18 mm die when necessary. Inspect top barrel threads for nicks and burrs. Chase with s4-27, or 5f-24,, die when necessary.

Thoroughly rinse the electrode end of the oily plugs in clean, unleaded gasoline. Do not hold the plugs immersed in the gasoline and if they are not coated with dirt or oil film, this operation may be eliminated. The blackened appearance at the end of the plug in the absence of heavy oil or lead deposit is not detrimental to its operation. This is acquired after a few minutes of operation in the engine. Permit the plugs to dry thoroughly after rinsing. Clean the inside of the upper shielded barrel. For this operation, use a smali piece of soft cloth wound on a wooden stick dipped in clean, urleaded gasoline. To remove moisture bake all plugs in an oven at 300o F. to 350o F. (149" C.:177" C.) for a period of two hours or more. Set the gaps to the recommended .0L2" clearance, using a flat, narrow width thickness leaf gage. Check the electrode gaps using a wire feeler gage. Bomb test aI spark plugs set at .0t2" gap. at 200 lbs./sq. in. For this purpose use COi or air, where an adequate and dependable supply of dry, high pressure air is available. After the above work has been completed, care is to be taken when storing the spark plugs awaiting installation in the engine. To prevent rusting, plugs should be coated with a light oil or suitable rust inhibitor. Be careful not to allow either the oil or the compound to enter the shielded banel or the inside shell around the nose of the core. In order to keep the plugs clean, and prevent moisture absorption, they should be covered by protecting caps screwed on both the shell and the barrel thread. The top or shielded barrel cap should be equipped with an internal

LLO2

SPARK PLUGS

gasket to insure an air-tight seal. As an added precaution, plugs should be stored in a heated compartment. This procedure is to be repeated at each period until the limiting factors outlined previously are RECONDITIONING In the event that the conditions of operation are such that it should require some reconditioning by the operator, the following procedure should be followed: plugs should be disasDlsassembly-Spark sembled, using snug-fitting socket wrenches. Open end wrenches should never be used as they ar-eliable to slip and causedamage. If the threads securing the core and shell together have a tendency to bind during the disassembling procedure, do not attempt to force the threads. Place the plugs in a rack, electrode end up, and pour a very small quantity of penetrating oil in the firing chamber. Place the plugs in a heat regulated oven with temperature maintained between 150' F. and 200o F. (66" C.93o C.) for at least twenty-four hours. This procedure will facilitate the disassembly in most cases. If difficulty is still experienced, it may become nece$saryto scrap the parts. large quantities of Shell Assembly-Where shells are being serviced and the facilities are available, removal of carbon and lead deposits is best accomplished by placing the shells in a heated salt bath, or a similar preparation which is recommended by the manufacturer. In small quantities, they may be soaked in clean, unlqqded srasoline to remove the oil and carbon. Hard darbon and lead deposits may be removed with a knife or round wire brush. A small wad of steel wool wound on a drill and used in a lathe or drill press chuck is also effective in cleaning the inside of the shell. Care should be taken to prevent damage to the internal threads, the core gasket seat, and electrodes. Rust may be removed by dipping in a L0% solution of suplhuric acid at L20o F. (49" C.) for a few minutes and then rinsing in cold running water. After drying, coat the shells with a light oil, or suitable rust inhibitor. All shells should be inspected for damaged hexagons, condition of the electrodes and buned threads. Damaged threads should be cleaned up with a tap or die, or in some caseswith a file. When the shell electrodes are burnt away in excess of the manufacturer's limit and can no longer be properly adjusted, they should be discarded and new shells used. On some makes, new electrodes may be inserted, as long as the shell is in otherwise good condition.

reached, at which time those makes of spark plugs which can have the center electrodes retipped or new shells to replace the ground electrbdes installed , are to be returned to the manufacturer, otherwise the plugs are to be discarded as unserviceable. OF SPARK PLUGS Core Assembly-Check the core assembly for defects. If the %6-27"or sl-24" elbow attaching threads at the shielded end of the plug are crossed or badly damaged, the core should be scrapped inasmuch as there would not be positive assurance that the elbow would be secured firmly in place. Small nicks or burrs can be cleaned up by iunning a die over the threads, or with a toolmaker's file. Check the mica insulation in the upper barrel for defects, such as deep scratches or gouging. Minor scratches are permissible. However, deep scratches or gouging may develop trouble later on. A definite crack in the insulation should be cause for rejection. Remove all traces of dirt and oil, etc. from within the shielded barrel. A small round wooden stick, or dowel, with several layers of clean cloth wrapped around it and dibped in clean, unleaded gasoline proves effective for cleaning the inside of the barrel. Examine the core threads for nicks, pitting, forms of corrosion, or mutilation. Small nicks or pits can usually be stoned out or removed with a fine toolmaker's file. Threads which are badly scuffed, during disassembly, are cause for rejection. Corrosion, if not too severe, may be tolerated. Check the amount of metal left on the center electrode shoulder in accordance with the manufacturer's instructions, and if worn in excess of the manufacturer's limit, the core should be scrapped. To remove the lead deposits which have accumulated on the mica core nose, it is recommended that the core be inserted in a motordriven cleaning socket and revolved at a speed of approximatelyl750 R. P. M. Socketsfor the varioG plugs should be obtained from lhe respective spar-k blue manufacturers. Preferably grade No. 180 Aloxite cloth should be used for this proce$s. However, J''{o. 0_0sa4dpaper will- also serve the purpose. Lead deposits are not of uniform hardnesii or equally distributed; hence it is possible that some sections on the core nose resistance to removal than other may offer greater -For this reason, the operator is causections. tioned not to exert too much pressure on the cloth in the early stages of cleaning. Following the removal of the carbon, lead deposit, etc., polish the mica using No. 300 Aloxite cloth or No. 000 Crocus cloth-in order to obtain a smooth finish. The operator is cautioned not to remove any more mica insulation than is absolutely nec-

1103

SPARK PLUGS essary to obtain a clean and well-polished core nose. Never use emery or carborundum cloth or paper, steel wool, file or sandblasting, as it is detlimental since particles from these materials might affect the plugs in the event that they become imbedded in the mica insulation. Sandblasting is too harsh on mica insulation and would wear away the insulation at a rapid rate. Care should be taken during the core nose cleaning operation to prevent unnecessary wear of the center electrode tips. If there is sufficient metal left upon the center electrode tip, it can be rounded off by inserting the core in the chuck of a motor-driven lathe and turning down the tip. Ottly enough material to obtain a smooth finish should be removed. The tip should be rechecked for contour after this operatron. On certain types of plugs, it is possible to retip the center electrodes when worn to an extent that thev exceed the manufacturer's limits. In this resiect, the manufacturer should be consulted. Examine the clean mica core nose surfaces for pits, burned areas, or unusual wear. Evidence of anv one of these defects should be cause for rei-ection. Check the diameter of the core nosie, using the gageprovided by the manufacturer. If the mica diameter adjacent to the core tip es through the narrow part of the opening in the ga1e,lhe, insulation has worn apay beyond the Safe point and is cause for rejection. Assembly-Using mica lubricant sparingly, on the lower threads, assemble the core into the shell of the plug. Normal tightening is sufficient. Over-tightening will only distort the core and perhaps damage it. The manufacturer of the particular spark plug should be consulted for the torque limits which generally is never in excessof 3501n.-lbs. (approximately 29 foot pounds). assembly, the spark plugs Bornb Tests-After should be tested in a pressure tester or bomb test at200lbs./sq. in. of COz. Air may be used providing special precautions are taken to exclude any moisture. All new or reconditioned spark plugs should g?p.at 200 lbs./sq. F" r"grrlarly across the .0L2" The duration of the test should in. pressure. -approximately fifteen seconds. If any be plugs fail to fire consistently at this pressure, theie may be a possibility of moisture having

collected on the core nose or in the shield chamber. Place such plugs in a heat regulated oven and bake them for approximately two hours at 250" F. to 350' F. (LzL' C.-I77o C.). Retest them after they have cooled sufficiently for handling. If they still fail to fire consistently after the operator has assured himself that the test equipment is operating satisfactorily, and that the flash-over is not occurring within the shield chamber, the plug is short-circuited and should be rejected. Practice is required to determine when a plug fires regularly in a bomb. With some types of plugs, the spark "hunts" from one electrode iroint'to another, firing across the point having the least resistance at the instant. To an inexperienced operator this hunting might appear to be a t'miss". After testing, the plugs should be coated with a light oil or a suitable rust inhibitor to pre,vent conosion, and protector caps installed on both ends of the plug. To avoid the effects of moisture, spark plugs should always be stored in a dry place. This is particularly important during the winter periods or damp weather. A cabinet, or a box, heated with one or more 100 watt electric light bulbs provides a suitable storage place. Terrnlnal Sleeves-Particular care should be exercised when installing the termir:al sleeves on the ignition wire. Cut just the specified amount of insulation from the conductor to permit the right length of wire to extend through the wire outlet. The insulation must bear firmly against the brass disc on the inside end of the sleeve. The ends of the ignition wires, constructed with a layer of cotton under the lacquered surface, should be dipped in an insulating varnish to about /s", and permitted to dry before terminal sleeves are applied to the wire. This treatment prevents the layer of cotton from acting as a wick should moisture find its way into the assembly. When installing the terminal in the plug it should be wiped perfectly cleaa, and aftei that not touched by the fingers as oil, acid, dirt, etc., will promote -eventual flashover, cause defailure of the sleeve. terioration, and The repeated installation of dirty sleeves in a spark plrrs results in contaminatlng the mica insulation on the inside of the barrel, which eventually will causefaulty operation.

t20L

CEAPTER XII

FUEL PUMPS GENERAL INFORMATION Iruel pump overhaul should only be undertaken at properly equipped overhaul shops where complete facilities for repair and testing are available. Ihe instructions contained in this chapter are reproduced from the manufacturers' handbooks PESCO FUEL (Pump

covering their products. If the necessary facilities and equipment are not available for overhaul, or additional information is required, it is recommended that the fuel pump manufacturer be called upon. PUMPS

Englneerlng Servlce Corporatlon Cleveland, Ohto)

DISASSEMBLY Instructions for disassembly are deemed unnecessary except for the following notations. Speclal Tools-Two special tools are required for disassembling Pesco Fuel Pumps, a wrench for loosening the lock nut and puller for extracting the front bearing. These tools are shown in Fig. 120I-. Special expansion tools are available also for removing and replacing the sleeve and rear bearing although they are not strictly necessary.

Sleeve and Bearlngs-It is recommended that the pump body be heated to about 250o F. (LzL" C.) in a gas oven or oil bath to eliminate unnecessary wear on the sleeve and bearings during disassembly. The sleeve and rear bearing can be removed with special expansion tools or by tapping the parts out on a soft wooden bench or block after the body has been heated. Experience shows, however, that these parts seldom require any attention for at least 4000 hours service.

INSPECTION AND REPAIR After disassembly, clean the parts with gasoline and inspect them carefully for damage and wear. All defective parts as well as those indicating wear in excessof the tolerances shown in Fig. 1206 must be replaced. Also observe the following: Blades-If the sides of the blades are rough or slightly scored, dress them carefully on a new, flat oilstone, but be careful to maintain the original radius on the edges. Smooth off any sharp corners at the ends of the blades which might score the bronze bearings but do not round them off excessively. Bearlngs-'Slight scoring of the bronze bearings may be corrected by lapping them carefully on a flat oilstone. DO NOT attempt to lap the seal surface of the front bearing. Unlversal Block-Examine the seal surface and tongues and smooth off any rough edges. Substitute a new part if the tongues are worn excessively. DO NOT attempt to repair the seal surface as it must be absolutely true to seat properly on the bearing face.

Seal Dtsc-If the seal surface is noticeably worn or scored, substitute a new part. DO NOT attempt to repair the seal surface. Rellef Valve-Inspect the valve to see that the edge is perfectly round and even and that the stem will allow free action in the gurde hole. Clean the guide hole thoroughly with a rag dampened with gasoline and wrapped on a wooden stick or metal rod. To reseat a valve, mount the valve housing on the pump body, insert the valve stem in the guide hole, place a short rod of soft brass or soft steel against the valve or in the spring hole and tap carefully with a wooden mallet. Valve Eouslng-See that the valve seat is round and even and that the integral check valves are in good order. If a ball does not seat properly, place the valve housing on a wooden bench or block, insert a %t" diameter rod of brass or soft steel through the hole in the spring retainer and tap lightly with a mallet until the ball is reseated. Gaskets-Discard used gaskets and substitute with new ones.

L202

25 DRILL 64

.19

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LOCKNUT WRENCH T- 160

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PUIIP ENGINEERINGSER. CORA Fig. 1201 - Special Tools for Pesco Fuel Pumps

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L205

PESCO FUEL PUMPS REASSEMBLY Heat the body to about 250" F. (121" C.) and insert the rear bearing and eccentric sleeve. Place the center pin in the bore of the rotor and the four blades in the rotor slots. This assembly unit can be held together with a rubber band until partlv inserted into the bore of the sleeve. While the body is still warm, insert the top, or front bearing using the special puller to protect the seal surface and to keep the bearing straight. Add the seal parts and drive coupling and tiehten the entire assembly with the lock nut. When assembling the seal parts, place enough oil on the seal surface to provide a film of lubricant, but do not oil excessively. Mount the valve housing on the pump body, referring to the instruction plate on the side of the housing. Add the valve and bellows assembly or diaphragm. * Fasten the cover to the housing and secure the cover screws and housing screws with safety wire. Finally assemblethe valve control spring, adjusting parts and lock nut. Assernbly Test-Test the pump for freedom of operation by turning the coupling with the fin-

gers. If the coupling will not turn, tap the assembly on a wooden bench or block to free the parts. Also, wash out the pump with gasoline to remove any particles of foreign matter. Disassemble the pump, if necessary, to recheck clearances and 6liminate tight spots. When the pumps turn freely after reassembly, proceed with the final test. *When assembling a new diaphragm or replacement valve assembly it is necessary to "preform" the diaphragm to allow for a slight depression at the center when the valve is seated. Preforming can be accomplished easily by assembling the parts in regular order but leaving the valve cover screws only finger-tight. Do not use a screw driver. By means of the adjusting nut, tighten the valve control spring almost to the limit, or enough to indicate that the valve is firrnly seated. Then tighten the cover screws with a screw driver and immediately loosen the valve adjustment to relieve excessive spring tension. Refer to the instruction sheet enclosed with the diaphragm or valve assembly.

rilYer., TEST Test equipment should include essentially a mounting fixture, an approved fuel flowmeter, a supply tank, tubing, a pair of globe valves for controlling intake suction and discharge pre$sure, and a pair of 30" U-tube mercury manometers for measuring suction and pressure. The mounting fixture should incorporate a suitable drive gear to be coupled to a ftH.P. variable speed electric motor. The flowmeter can be replaced by a stop watch and graduated container or bucket and scales. A 30" mercury manometer will suffice for pressures up to 15 lbs./sq. in. the manometer must be increased two inches for each additional pound. The equipment can be arranged as suggested in the test set-up diagram, Fig. 1204. The procedure outlined in the following paragraphs represents a modification of the standard factory test procedure, and although it has been simplified as much as possible, it can nevertheless be considered a satisfactory check on ordinary service work if observed closely. The thoroughness of the test will depend on the available range of speeds. If for any reason a departure from this procedure is contemplated, an explanation should be forwarded to the Pump Engineering Service Corp. for comments and recommendations. In the following tests the relief valve is to be blocked off from the pump except for the valve regulation test. Substitute a suitable cover plate for the valve housing or mount the housing at

90o from its normal position. The lower or lowest drain hole next to the mounting pad should be left open. I Break-ln-Run the pump for 15 minutes pumping gasoline with no restrictions in the fuel lines. Then disconnect the fuel lines and blow out the gasoline with compressed air while the pump is running. Finally run the pump dry for five minutes. the fuel lines to the pump, Dry Ltft-Connect and close off the valve in the intake lines so that no fuel can enter the pump. Start the pump and measure the mercury differential on the suction manometer, preferably at several speeds. Compare the readings with the minimum allowable dry lift indicated in the curves, Fig. 1205-4. Capaclty-Measure the capacity or rate with 4 inches of mercury inlet suction inches of mercury discharge pressure. mum allowable capacity is indicated curves,Fig. 1205-8.

of flow and 8 Miniin the

Valve Regulatlon-Mount the valve and valve housing on the pump in normal position, that is, with the intake side of the housing next to the pump intake port. Run the pump at approximately 2000 R. P. M. and by means of the hand valve in the discharge line, restrict the fuel flow as indicated in the curves, Fig. 1205-C with 4 inches of mercury suction. Then set the relief valve adjustment for 8 inches of mercury pressue (or

L206

PESCO FUEL PUMPS

any desired pressure). Vary the rate of flow from 0 to twice the original setting and note the effect on the discharge pressure. The allowable pressure variation is plus or minus one half pound per square inch (1 inch of mercury). the foregoing tests any seal Seal Test-During leakage is cause for rejecting the pump. Fuel leaking past the seal will drip from the drain hole. the 4O-hour inspection period Vent Eole-At clean the vent hole in the special plug in the valve supercharger connection. Or, if the vent hole is in the adjusting nut, remove the snap dtg,

take out the protecting screen, and clean both the screen and the vent hole. Blocking of the vent hole will result in pressure fluctuation and a general increase in pressure with altitude. Do not apply air blast to the vent hole because it might damage the sylphon or diaphragm. a safety precaution the vent Important-As hole is restricted to minimize loss of pump suction in event of damage to the sylphon or diaphragm. The manufacturer, therefore, strongly cautions against enlarging the vent hole becausethe result would be the creation of an unnecessaryhazard.

a o

MERCURY

I

,.-txouerenT\ FLOWMETER CAN BE REPLACED BY STOPWATCH AND GRADUATED CONTAINER

VALVE

VALVE

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TO REGULATE PRESSURE

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TO REGULATESUCTION

P E S C OF U E L P U M P MOUNTEDON TEST STAND AND COUPLED TO '/2 HP. MOTOR

FUEL SUPPLY TANK

tur.tp EtitctNEEB|No sERylcE

Fig. 120a -

Diagram of Setup for Testing Pesco Fuel Pumps

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Fig. 1205

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CECO FUEL PUMP (Chandler-Evans Corp. South Merlden, Conn.) DESCRIPTION

The Ceco fuel pump is of the rotary vane type oneratine in either direction of rotation. It is piovided- with a pressure relief and regulating valve using a continuous molded diaphragm and seal, no valve stem or other part extending through the diaphragm. Pressure may be set to any desired value within its range by adjusting the fillister head screw at the end of the valve cover. This maintains a uniform discharge pressure throughout a wide variation in intake suction, discharge rate and pump speed. The top of the diaphragm is vented to the atmosphere through a screened L/a" pipe plug. This outlet may be connected to the carburetor air scoop or

turbo-supercharger for maintaining uniform discharge pressmreat increasing altitude. The relief valve is so balanced as to vary the discharge pressure directly as the supercharger pressure. The by- valve is incorporated with the pressure relief valve to allow fuel to freely through the idle pump, when a separate manually operated pump is the source of supply. The drive shaft has sufficient lateral movement to allow for a slight misalignment and is provided $rith a metallic seal that required no adjustment. L/s" pipe holes are provided for draining any fuel that may possibly have escapedthrough the seal.

INSTALLATION Remove shipping plugs and pipe plugs, thereby draining the oil shipped in the pump. Turn drive shaft with fingers to check operation. Flush with clean gasoline. Lubricate pump through one of the open ports with light engine oil. Again turn shaft several revolutions by hand and drain out excessof oil. Place in any suitable position by rotating the entire pump on its square mounting flange or in the case of pumps with a rotatable rectangular flange by removing the four screws holding the flange on to the pump body and rotating. Next determine the direction of rotation of the engine. Arrows on the anti-drive end cover of the main housing in its normal position (so that the printing can be read normally when the pur4p is held upright with the valve assembly at the top) indicate the inlet port for either direction

of rotation. The relief valve housing is mounted on the pump body with four screws, the position depending upon the direction of flow. A plate on the valve housing indicates the end that should be over .the discharge port. The valve housing must be reversed when the direction of rotation is reversed. Pipes must be connected accordingly. Pumps are delivered with relief valves generally set at four pounds per square inch discharge pressure, at three hundred pounds per hour flow, at 2000 R. P. M. To change this setting, loosen the hexagonal lock nut at the top of the relief valve housing cover and turn the fillister head screw ciockwise to increase pressure or counterclockwise to decrease pressure. Reset hexagonal cap lightly with a short wrench, and lock wrre.

DISASSEMBLY To remove rotor assembly remove fout screws, rear plate assembly, and drive shaft. If leakage of the shaft seal occurs, the seal faces of the nitralloy seal collar and bronze bushing should, at this time, be very carefully lapped.

tool No. F2. Rotor assembly will then fall out intact. To remove the liner and drive end bearirg, remove the liner set screw, and immerse pump body in oil at 250o F. (12L' C.). When hot, these parts can then be pushed out freely with a push rod from the drive end.

Remove four screws and the anti-drive end housing cover, being careful that the center pin does not fall out. The anti-drive end bearing can be removed at ordinary room temperature by pushing on rotor from the driving end using

The relief valve may be removed by loosening the four screws holding the relief valve housing and cover, following which the whole assembly will fall apart.

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ASSDMBLY Clean all parts carefully in gasoline. Immerse pump body in oil at 250' F. (121' C.). Insert drive end bearing by holding it on a tapered wood plug. Reheat if necessary, then insert liner in similar manner, using a r/e" pin to line up the liner groove with the set screw hole. After cooling, install the liner set screw and its gasket, and insert the complete rotor assembly. Then place anti-drive end bearing carefully into pump body, and press squarely in place with an arbor presn. Do not heat when installing this bearing. Replace gasket and cover and draw down four screws uniformly. Next assemblethe shaft and seal parts in drive end of pump that are held in place by four screws. Tighten screws uniformly and check for freedom of rotation of the pump mechanisrn. If free,

stake the four screws in place. Assemble the relief valve in the valve housing, being sure that it rests squarely on the valve seat and that it works freely. Assemble the other parts of the valve, such as diaphragm, spring and spring follower; and replace the valve housing on the pump body in the proper position, depending upon the direction of rotation, with the four screws. Tighten uniformly. The lock wiring of all screws and the hexagonal lock nut should not be done until after the pump has been checked and the pressureregulated. It is recommended that all gaskets and rubber substitute packings be replaced with new ones. On pipe threads use only an approved pipe sealing compound.

INSPECTION ANI) MAINTENANCE Fig. No. 1207 shows cross-sectionalviews of the pump. Clearances should be checked as shown for both desired values and those maximum values above which parts should be replaced. Special attention should be paid to see that the bore of the liner is smooth, also that the working surfaces of the vanes are smooth and that the metallic drive shaft seals are carefully lapped. The square end of the drive shaft and its mating square hole in the rotor should not be worn ex-

cessively. When assembled, the pump should turn freely and show no sign of binding. The diaphragm should be carefully checked to see that there are no cracks or breaks, and that it is very flexible. The valve shall fit freely in the valve housing. The valve seat shall have a clean square edge all around, and may be checked with Prussian blue to insure proper seating of the valve.

1301

CHAPTER XIII

INSTRUCTIONS FOR STROMBERG NA.RgA AND NA-RgB CARBURETORS OVERHAUL-NA.R9A carburetor should be disI)lsassembly-The assembled for cleaning and inspection each time the engine is given an overhaul. After the carburetor has been removed from the engine and the hot spot and air intake or heater taken off, the halves of the carburetor may be separated bv the removal of the fillister head screws at parting surface and the venturi set screw. t[e -economizer needle, mixture control needle, The Dump sleeve and venturi are held in the throttle bodv. The pump sleeveshould be slipped off the operating stem as soon as the halves are separated as it is a brass stamping and is easily bent if allowed to drop on the floor or bench. If it is necessary to remove the venturi, it will have to be driven out using a wooden plug similar to that shown in Fig. 1301-.{. AU parts in the bodies, with the possible exception of the idle discharge jet assemblies, should be removed to enable a thorough cleaning and inspection. bodies and Cleanlng and Inspectlon-The all parts should be thoroughly cleaned in gasoline, and all agesblown out with compressed air. All variable parts should be checked to see that their sizes are in accordance with the latest carburetor specification sheet for the engine. Inspect all moving parts to see that they iio not have excessiveclearance. ordering replacement Replacements-When parts it is necessary to give complete informaiion concerning the parts desired to avoid delay in shipment or the receipt of wrong parts. Wherever possible, the serial number of the carburetor should be given. A careful reference to the attached assembly drawing (seeFig. 1302) to determine the correct part number and name, and if marked with an asterisk ( *) giving the size as stamped on the piece, will greatly facilitate service. A specification sheet giving the sizes of iets, fuel level, economizer setting, etc., will be -furnished no charge if you will write to the Bendix Products Corporation, Stromberg Carburetor Division, South Bend, Indiana, advising the model of your engine. Parts Price lists will also be furnished on request. P-t9223 covers a complete set of gaskets for this model. headless screw plugs below Reassembly-All the fuel level should be assembled with shellac, being careful not to get it on the end of the plug where it will come off and be carried by the gas into one of the metering orifices. Headless screw plugs above the fuel level and all other threaded parts screwed into the bodies should have a compound of graphite and castor oil put on the threads.

When it is necessary to replace the throttle shaft, pump lever or throttle stop, assemblethe Iever and stop as shown in Figure 1301-8 and D. The throttle valve should be so fitted that it excludes practically all tight when in the closed position. It is recommended that in replacing a float needle valve or a needle valve seat that these two assemblies be replaced at the same time, as it is very difficult to fit a new needle to an old seat or a new seat to an old needle. The float level should be fu" below the parting surface and is dependent upon the thickness of the gasket under the needle valve seat. The level should be checked under the conditions encountered in service as regards the fuel used and the fuel pressure or head at the carburetor. Those carburetors having a Yro" needle seat or gravity type, which is that one used with a gravity feed system having lessthan a9'1" fuel head, should have the level set using 1 tb. pressure (39" gasoline .71-0sp. gr.) at the carburetor. Those carburetors having a .L96" needle seat or pressure type, which is that one used with a gravity feed system having more than a 97" fuel head or a fuel pump, should have the level set using 3 lbs. pressure (117" gasolineat .7I0 sp. gr.). If after assembling, the level is not correct, remove the needle valve seat and put in thicker gaskets to lower the level and thinner gaskets to raise it. A change in gasket thickness of t4ntt wrll change the level approximately s/a". When any parts of the mixture control system are replaced, care should be taken to see that they are assembledcorrectly. As previously explained the needle valve is operated by an eccentric pin which is a part of the mixture control stem assembly. The mixture control stop is pinned to this same stem and it is important that the stop be located on it at the proper angle with the eccentric pin. This may be done by placing the mixture control stem, without the stem nut, spring and packing, in the throttle valve body with the eccentric pin away from the pump mechanism and turning it until the distance from the parting flange surface to the pin is Yra"(seeFig. 130L-E). With the stem held in this position, place the mixture control stop against the shoulder of the stem with the stop against the stop in the body (full rich position) and drill through the stop and stem. Then assemble the spring, packing, and nut on the stem, press the stop on against the nut, and pin in place.

t302

CARBURETORS The mixture control needle is screwed into the needle holder and these parts should be so adjusted that a needle valve travel of r%t" + .000", - rAt" and a lever travel of 75o to 80o is obtained. An approximate adjustment may be obtained before assembling the needle valve in the upper half by setting the bottom of the holder slot LrAz" from the main body parting surface with the needle valve held down against the needle valve seat (see Fig. 1301-C). \)Zhen this preliminary adjustment has been made, assemble the two halves together and determine if the needle has r%a,, + .000,,, _ |(t,, travel. The needle travel may be checked by removing the jet and plug below the needle and using the simple apparatus shown in Fig. 1301-4. When in the full lean position, the needle stops against the needle valve seat, when in the full rich position the stop strikes the stop lug. When the proper adjustment has been made pin the needle as shown in Fig. 1301-Cto prevent its changing in service. In assembling the needle in the carburetor the slot in the holder should be placed with the opening away from the pump mechanism.

The position of the economizer needle adjusting nut determines the engine speed at which the needle is lifted off its seat, and it is therefore important that this be set correctly in order that the engine will not be operating on too lean a mixture near full throttle or too rich a mixture at cruising speeds. The throttle opening at which the economizer should come in is given on the specification sheet as the economizer setting. This is the travel in degreesof the throttle valve from closed position to that point where the forked lever on the throttle shaft engages the economizer needle adjusting nut. To find the angle which the valve makes with the horizontal flange surface when the economizer comes in, add the throttle valve angle (given on the specification sheet) to the economizer setting. If the economizer setting is 33' and the throttle valve angle is 20o, the angle which the throttle valve will 'rnake with the horizontal flange surface when the forked lever engages the economizer needle is 53o. When the final adjustment is made, use another nut to lock or jam the adjusting nut, being careful, however, not to change the setting.

OVERIIAUL-NA.R9B The NA-R9B model is the same as the NARgA model except that a priming device is incorporated in the mixture control assembly - of The instructions coverins the the NA-R9B. NA-R9A are, therefore, applicable to tht NARgB except that part of them which covers the method of assembling the mixture control needle and stop. Prlmlng Systern - The priming system in the carburetor consists of a valve on the mixture control stem, with agesso arranged that fuel from the accelerating pump esthrough the valve to the pump discharge nozzle in the barrel of the carburetor when the mixture control is full rich, or esthrough the valve to an rA" pipe connection for the primer system when the mixture control is full lean. Fuel is diverted to the primer system when the mixture control is approximately 55o from the full rich position. To prime the engine the following procedure should be followed: (1) With the mixture control set full rich and the throttle closed, turn on the fuel. (2) Turn off the fuel when carburetor is full. (3) Set the mixture control full lean, which opens the channel to the priming system. Move the throttle slowly, thus operating the accelerating pump and forcing fuel through the priming system to the engine. The number of strokes required to satisfactorily prime the engine will have to be determined by experiment. (4) When sufficient priming charge has been pumped to the engine, close the throttle and set the mixture control full rich. (5) Turn on the fuel and start the engine.

Replacernents - When any part of the mixture control and primer shaft assembly are replaced, c,ale should be taken to see that they are assembled correctly. The primer valv-e should be lapped in, using a very fine lapping compound. Care should be taken to see that the valve seats perfectly and after assembly should be checked to see that it shuts off the gas from the pump discharge nozzle when mixture control is full lean and throttle operated. It is important that the stop be assembled in correct relation to the eccentric pin which operates the mixture control needle. This may be done by making up the complete assembly, including the lever, indicator plate and nut, and assembling it in the throttle valve body. With the stop in the full rich position (against the large head screw) the shaft should be adjusted so that the dimension from the shaft to the eccentric pin is .330" (see Fig. 1304-A). When this adjustment has been made drill and pin the stop in place. The mixture control needle is screwed into the needle stem and these parts should be adjusted to obtain a needle valve travel of r%t" plus .000", minus rAE";a lever travel of 75o to 80o, and the primer valve to open between 55o and 60o lever travel. An approximate adjustment may be obtained before assembling the needle in the throttle valve body by setting the bottom of the stem slot r%2" from the main body parting surface with the needle valve held down against the needle valve seat (see Fig. 1304-8). When this preliminary adjustment has been made assemblethe two halves together and check

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1304

CARBURETORS to see if the above requirements are met. The needle travel may be checked by removing the jet and plug below the needleand using the simple apparatus shown in Fig. 1304-C. When the final adjustment of the needle has been made so that all the above requirements are met, pin and solder the needle as shown in Fig. 1304-B to pre-

vent it changing in service. In assembling the needle in the carburetor the slot in the needle stem should be placed with the opening away from the pump mechanism. P-20L46 covers a complete set of gaskets for this model.

NA.ROA CARBURETOR SPECIAL AND STANDARD PARTS See Specification Sheet (Fig. 1302) for special parts applicable to your carburetor. ECONOMIZER NEEDLE ASSEMBLY: Std. P-L7321- 5o and 34o P-17430-L5o and 60o P-18036- 2o and 34"

ECONOMIZER SEAT: Std. P-17328-No.32 P-17436-No.34 P-I.8028-No. 44 MIXTURE CONTROL NEEDLE: std. P-L4L70-L5' P-L7432-30" MIXTURE CONTROL NEEDLE STEM: Std. P-15623-Usewith P-14L70 P-17435-Use with P-t7 432 MIXTURE CONTROL NEEDLE STEM PIN: Std. P-6587-Use with P-15623 P-7018-Use with P -17435 MIXTURE CONTROL NEEDLE ASSEMBLY: Std. P-16283-Consistsof P-14170,P-15623,and P-6587 P-L74}7-Consistsof P-L7432,P-L7435and P-7018 MIXTURE CONTROL NEEDLE GUIDE: Std. P-t4L7}-Use with P-15623 P -t7 434-Use with P-L7435 MIXTURE CONTROL WASHER: Std. P-LL726-Vse with P-14170 P-17431-Usewith P-L7432 MIXTURE CONTROL WASHER: Std. P-1417t-Use with P-L4L70 P-L7433-Use with P-I7 432

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F IT T I N G M I X T U RE C O N TR O L S T O PA N D S T E M .

A M I X T U R EC O N T R O L LEVERIN FULL RICH POSIT]ON.

=.'rt\ -ro -_

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c ' s r N KF o R P - 6 s 9 7P t N AFTERADJUSTING R I V E T E N D SO F P t N & FILE FLUSH.

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P R E L I M I N A R YA D J US T M E N T O F M I X T I J R E C O N T R O LN E E D L E V A L V E & H O L D E R .

B Fig. 1304

C

1308

CARBURETORS NA-ROB CARBURETOR SPECIAL AND STANDARD PARTS SeeSpecificationSheet (Fig. 1304) for specialparts applicable to your carburetor. ECONOMIZER NEEDLE ASSEMBLY: Std. P-L7327- 5" and 34" P-17430-15oand 60o ECONOMIZER SEAT: Std. P-t7328-No. 32 P-L1436-No. 34 MIXTURE CONTROL NEEDLE: std. P-14170-15" P-L7432-30' MIXTURE CONTROL NEEDLE STEM: Std. P-15623-Use with P-L4L70 P-L7435-Use with P-L7432 MIXTURE CONTROL NEEDLE STEM PIN: Std. P-6587-Usewith P-15623 P-7018-Use with P-L7435 MIXTURE CONTROL NEEDLE ASSEMBLY: Std. P-16283-Consistsof P-14170,P-15623and P-6587 P-L7437-Consistsof P-17432,P-17435and P-7018 MIXTURE CONTROL NEEDLE GUIDE: Std. P-14L73-Use with P-15623 P-L7434-Use with P-L7435 MIXTURE CONTROL WASHER: Std. P-7L726-Use with P-L4L70 P-L74}I-Use with P-L7432 MIXTURE CONTROL WASHER: Std. P-L4L7L-tTsewith P-L4L70 P-L7433-Use with P-L7432

1309

INSTRUCTIONS FOR STROMBERG NA-RgCT ANI) NA.RgCz CARBURETORS OVEREAUL I)lsassembly-The carburetor should be disassembled for cleaning and inspection each time the engine is given an overhaul. After the carburetor has been removed from the engine and the hot spot and air intake or heater taken off, the halves of the carburetor may be separated by the removal of the hexagon nuts at the parting surface, the venturi suction tube for the economizer and the venturi set screw. The economizer needle, pump sleeve and venturi are held in the throttle body. The pump sleeve should be slipped off the operating stem as soon as the halves are separated as it is a brass stamping and is easily damaged if allowed to drop on the floor or bench. If it is necessary to remove the venturi, it may be necessaryto use a wooden plug similar to that shown in Fig. 1307-A to drive it out. All parts in the bodies, with the possible exception of the idle discharge jet asiembly, should be removed to enable aih6rough cleaning and inspection. The economizer needle and diaphragm may be removed by removing the- nuts- holding the economizer cover to the throttle body. The assembly containing the mixture control plates and primer valve may be removed from the throttle body for a more complete disassembly. The automatic mixture control unit should be overhauled in strict accordance with the instructions issued on that unit. bodies and Cleanlng and Inspeetlon-The all parts should be thoroughly cleaned in gasoline, and all agesblown out with compressed air. Alt variable parts should be checked to see that their sizes are in accordance with the latest carburetor specification sheet for the engine. Inspect all moving parts to see that they do not have excessiveclearance. ordering replacement Replacements-When parts, it is necessaryto give complete information concerning the parts desired to avoid delay in shipment or the receipt of wrong parts. Whenever possible, the serial number of the carburetor should be given. A careful reference to the assembly drawing (Fig. 1309) to determine the correct part number and name, and if marked with an asterisk (*) giving the size as stamped on the piece, will greatly facilitate service. A specification sheet giving the sizes of jets, fuel level, economizer setting, etc., will be furnished if you write to the Bendix Products Division of Bendix Aviation Corporation, South Bend, Indiana, advising the model of your englne. Parts price lists will also be furnished on request. P-61307 covers a complete gasket set for the NA-RgCl and P-61308 covers a gasket set for the NA-R9C2 carburetor.

Reassembly-All the headless screw plugs below the fuel level should be assembled with shellac, being careful not to get it on the end of the plug where it will come off and be carried by the gas into one of the metering orifices. Headless screw plugs above the fuel level and all other threaded parts screwed into the bodies should have a compound of graphite and castor oil put on the threads. When it is necessary to replace the throttle shaft, pump lever or the throttle stop, assemble the lever and stop, as shown in Figures 1307-8 and 1307-C. The throttle valve should be so fitted that it excludespractically all light when in the closed position. It is recommended that in replacing a float needle valve, or a needle valve seat, that these parts be replaced at the same time, as it is very difficult to fit a new needle to an old seat or a new seat to an old needle. The float level should be V4" below the parting surface and is dependent upon the thickness of the gasket under the needle valve seat. The level should be checked under the conditions encountered in service as regards the fuel used and the fuel pressure or head at the carburetor. If, after assembling, the level is not correct, remove.the needle valve seat and put in thicker gaskets to lower the level and thinner gaskets to raise it. A change in gasket thickness of Y64"will change the level approximately 5/a". When any parts of the mixture control cover assembly are to be replaced, the shaft and stop should be assembled as shown in Fig. 1307-D. If the valve plates are to be replaced, they should be lapped in with a very fine lapping compound so that any possibility of air leakage wilt be eliminated. The cruise valve stem and lever should be assembled as shown in Fig. 1-307-E. Upon completion of the carburetor assembly, the economizer should be set to open at the value specified on the specification sheet. The venturi suction tube through the wall of the venturi should pe plugged ald t};re %" pipe plgg in -the econonuzer cover should be removed and a source of vacuum connected to this chamber. The small 10-32 plug in the economizer adjustment screw in the cover should be removed and an Ames Dial Gauge should be assembled so the leg is resting against the economizer needle stem as shown in Fig. 1307-F. The vacuum should be increased until the Ames dial indicates that the needle has started moving and that point should be taken as the opening point. NOTE: A water manometer should be connected to the 10-32 manometer connection on the economizer

1310

CARBURETORS cover so the correct suction may be read in "inches of water". If the opening point is not as specified on the specification sheet the lock nut on the adjustment screw should be loosened and the necessary adjustments made. It is essential that there are no leaks around the gasket surface of the carburetor or around the mixture control assembly, therefore, the carburetor should be water-tested. Plates and

gaskets should be assembled to both flanges of the carburetor and 3 to 5 lbs./sq. in. air pressure applied to the inside of the carburetor through a connection in one of the plates. NOTE: Do not exceed 6 lbs./sq. in. pre$sure as the float might be damaged. The carburetor should then be submerged in water and any leaks found and repaired. Safety wire the carburetor before installing on the engine.

1311

AUTOMATICLEAN POSITION

MANUA- FULL RICH POSITON

MANUALFULL LEAN POS]TON

IDLE CUT-OFF8 PRIMERPOSITION

MIXTURE CONTROLAND CRUISEVALVE POSITION

A PRIMERVALVES PUI'P DISCHARGENOZZLE TIXTURE CONTROLSUCTIONNOZZLE

MIXTUREOONTROLPLATE (FIXED) TURE CONTROLPLATE (MOVEABLE}

VENTURITUBE MAIN DISCHARGE AUTOMATIC MIXTURE CONTROLNEEDLE AIR BLEEDER

;N N---

TOMATICMIXTURE CONTROL

@ cnursevALvEPLATEs

MAIN AIR BL1ED ARM MAIN AIR BLEED HOLES

JE @ cnurse VALVEMETERTNG @ econoMEERMETERTNG

MAN ilETERING .JET

AUTOTATICRICH POSITION

B

Fig. 1305

t3L2

9 )ECONOMIZER SP

@ econoMrzE DIAPHRAGM

E C O N O M I Z ESUCTION R NOZZ LE

NEEDLE 5 ) ECONOMIZER VALVE

ECONOMIZE M E T E R I N GJ E T VACUUMECONOMIZER SYSTEM

Fig. 1306

1313

NA.RgCI & NA.RgCz VENTURI REMOVAL PLUG

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A DRILL & REAM FOR T A P E R P I N D U RI N G

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M E T H O DO F A S S E M B L I N GP U M P

END AS SHOWN.

F

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I

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N A-R 9 C z C R U IS E VA L VE STE M E C O V E R A S S E M B L Y

E

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P-6r320 P-6r354

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1315

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P-r3531 P-[640 P-19285 P-60627

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STROT'8ERG CAREURETOR

1401

CIIAPTER

XIV

MAGNETOS GENERAL CONSTRUCTION (Type SB9R) Scintilla SB9R magnetos employ the principle of rotating magnet and stationary coil. Rotation of the four pole magnet produces reversals of the magnetic flux through the core of the coil. This produces a high tension current in the secondary ivinding. Ttrls high tension current is conductei

by the distributor to the spark plugs. The condenser, connected across the breaker cont4cts, is located on top of the coil. The hreaker is held in position by two hold-down springs which makes it quickly removable for inspection without the use of tools.

DISASSEMBLY The following procedure of disassembly is recommended to avoid any possibility of breakage. As the parts are removed, place them in order on the bench to facilitate reassembly. Blocks-Remove the distributor Dlstrlbutor blocks after having released their spring clamps. Magneto Coll Cover-Take out the two fastening screwsand lift offcover. Breaker Cover-Remove safety pin and breaker cover fastening screw, after which the cover can be removed. Magneto Coll-Remove the two coil fastening screws and clamps after which the coil can be removed. Care must be taken so as not to break or damage the high tension carbon brush when removing the coil. The felt pad under the coil can be taken out by hand. Contaot Breaker Assernbly-Remove the breaker assembly after having taken out the two breaker hold-down springs. On fixed spark magnetos, also remove the clamp assembly which securesthe breaker cup to the housing. Remove the point assembly after taking out its two securing screws. Inspect the point assembly as outlined under "Inspection of Point Assembly". Front End Plate, Rotatlng Magnet, and Magneto Ilouslng-Remove the front end plate after having taken out its two securing screws and the four lock nuts. Use Socket Wrench No. 4-1337 for the lock nuts. Tap each side of the front end plate lightly with a rawhide mallet to remove it from the housing. Remove the distributor cylinder after prying out the lock ring with a small screw driver. Remove the cup from the end of the large distributor gear hub. Unscrew the lock nuts on the end of the distributor gear axle and lift off the distributor gear. Do not loosen the two

screws which sec'rre the distributor gear axle to the front end qlate-unlgss the axle is-damaged and must be replaced. This will maintain lhe original adjustment fo1 t_hegears. The top ball and cage assembly and the spacer with the shim washers will come out as lobse parts when the distributor gear is lifted from tlie axle. Make sure that the same spacer and shlrn washers are used when reassembling as this will give, in the majority of cases, the correct adiustmenf between the axle and gear. It is goodpractice to wire.the spacer and shim to one ball and cage assembly to prevent from being misplaced. If the bearings of the distributor gear axle need replacement, the outside race foi the bearing which came out as a loose part and, also, th6 complete bearing and retainer at the othef end of the gear hub, must be pressed out. To facilitate this, it is suggestedthat a small pressingdisc of the size and shape shown in Fig. 1401 be used. This disc can be placed inside oT the sear hub with its flat face in with each outer race as indicated. Remove the rotating magnet from the housing and place it on a clean part of the bench to mak6 sure that small chips oi particles do not come in wlth rt. Remove the insulating plate from the housing after having taken out its two securing screws which also hold the safety gap bridge. Replacernent of Drlve Shaft and Breaker End Ball Bearlngs-If any one part of a ball bearing is defective and needs replacement, the cornplete bearlng rnust be replaced. The outer ball races are insulated from the magneto by insulating strips and are also backed by washers of the same material as used in the insulating strips. Remove the outside race from the front end plate with Puller No. 4-222 and remove the inside race from the magnet with Puller No. 4-243.

t402

MAGNETOS

Remove the outside baII race from the housing with Puller No. 4-218 and the inside race from the magnet with Puller No. 4-235. Before removing this inside race, the cam must be taken off with Puller No. 4-241. Before installing new races in the front end plate and housing, first put in the flat insulating washer in the bottom of the recessfor the bearing so that the cut in it will line up with the oil recess. Then spread a few drops of oil evenly over one side of the insulating strip. Bend the strip in a circular form with the oiled side inside and overlap the ends enough to allow the strip to fit Ioosely into the recess for the outer race.

When it is released, it will expand against the walls and the ends should overlap slightly in the recess cut for them. Press in the outside ball race for the front end plate with Tool No. 4-136, and the outside ball race for the housing with TooI No. 4-134. Press on the inside ball race for the drive shaft end bearing with Tool No. 4-229 which is also used for pressing on the small distributor gear. The small distributor gear can be removed with Puller No. 4-233. Press on the inside ball race for the breaker end bearing with Tool No. 4-232.

INSPECTION Inspectlon of Magneto lfouslng-See that the pole shoes, the adapter and stud assembly, and all studs are tight in place. Examine the interior of the housing. If it is evident that the rotating magnet rubs, scrape out the housing slishtlv. Make sure that all threaded holes, paiticularly those in the pole shoe extensions for the coil securing screws, are clean and in good condition. Examine the outside race carefully. If it is found unsatisfactory for further service, the complete ball bearing assembly must be replaced. (See "Replacement of Drive Shaft and iJreaker End Ball Bearings" for tools required.)

Inspectlon of the Rotatlng Magnet-Make sure that the magnet shaft is not bent as it is important that the ground surfaces of the pole pieces and the cam pilot extension be within .002" concentric with the bearing pilot seats. (For testing magnet strength, see "Magnetic and Electrical Test".) Replace any ball bearings which show noticeable wear, roughness, or looseness. The complete ball bearing assembly must be replaced when any one part is defective. The cam must have'a comparatively close fit on its shaft and must run true within .001" full indicator reading (see Fig. L402, Tolerance Chart). Check the small distributor gear for burrs or excessive wear of the teeth. If this gear is replaced, it is recommended that the large distributor gear also be replaced. When the small distributor gear is meshed with the large distributor gear during reassembly, the backlash should not exceed.006" (seeFig.1402, Tolerance Chart). Remove all chips or particles of dirt which may have adhered to the rotating magnet. Inspectlon of the Coll-Examine the rubber housing for cracks and make sure that all screws are staled or provided with lock washers. Make sure that the carbon brush is in good condition. For electrical test of the coil and condenser see "Magnetic and Electrical Test".

Fig. 1401

of the Front End Plate-See that Inspectlon -felt strips are in place and that the oil cover the closestightly. Cleari the oil tube which Ieads to the drive shaft ball bearing with compressedair. Examine the outer ball race of the drive shaft ball bearing. Ifit is found unsatisfactory fol further service, the complete ball bearing assembly must be replaced.

1403

MAGNETOS

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1404

MAGNETOS of Large Dlstrlbutor Gearfnspectlon Examine the large distributor gear for burrs or excessive wear of the teeth. If this gear is replaced, the new small distributor gear should be installed. The gear should turn freely with the least possible end play between it and the axle. The bearings must be cleaned, examined, and repacked with Keystone No. 44 Grease. Inspectlon of Maln Cover wlth Booster and Ground Terrnlnal Block-Clean out the oil tube which leads to the breaker end ball bearing with compressed air. Examine the booster and ground terminal block for defects or cracks. Make sure that the felt strips are in good condition and tight in place. Inspectlon of Dlstrlbutor Bloaks-See that the electrodes are clean and tight in place. If new electrodesare installed, they must be checked with Template No. 4-L40 to insure that the required clearance between them and the distributor cylinder segments is maintained. (See Tolerance Chart.) Use Tool No. 4-8092 for machining distributor block electrodes newly installed. Cyllnder and of Dlstrlbutor fnspectlon B oolt er Collector Rlng -Examine the dielectric material for defects or cracks. Check the height of the distributor cylinder segments in Gauge

No. 4-7264. Segments should be replaced when they have burned away .015" as indicated on the gauge. Inspectlon of the Contaot Polnt AssernblyWhen inspecting the points, the breaker main spring should not be raised beyond the point giving Yrc" clearance between the movable and stationary points. Further tension of the main spring caused by raising it beyond this point will result in the weakening of the main sprrng. Check the main spring tension with Scintilla .the Gauge No. 4-9713. It is important that hook of the gauge be applied on the main spring adjacent to the point as illustrated at E (Fig. 1403). Main springs that have been in service and have a tension of not less than 15 ounces will be satisfactory for further service. New main springs should have a tension of 20 to 32 ounces. If the main spring tension as checked by Scintilla Gauge No. 4-9713 is too low, it can be raised by removing washer No. 10-3768 (Fig. 1403). If it is too high, it can be lowered by inserting an additional washer No. 10-3768. The other function of washgr No. 10-3768is to obtain maximum ing surface between the points. Examine the points for evidence indicating excessivewear. Mounds or peaks appearing on the surfaces should be removed. It is not considered necessary to remove slight pits which appear on the surfaces unless they are in excess of I0/o of the total area. Dressing of the s should be undertaken only by the most experienced operator and can be accomplished by using the Scintilla Dressing Tool No. 4-12L76,the Scintiila special cut File No. 4-12177,and StoneNo. 4-12868. Normal operation of the magneto causes a certain amount of wear to take place on the top of the cam follower. This wear is indicated by a small depression worn in the top of the cam follower at the point where it lifts against the end of the main spring. The distance between the Iowest point of this depressionand the top of the spring on which the cam follower is riveted should be checked at each overhaul. This distance should be /n" or over. If it is less than Yn", d new cam follower should be installed.

Fig. 1403

If the above inspection indicates that the rires replacement of breaker assembly requires parts, use the No. 4-12967C ontact Point Reassembly Fixture.

r405

MAGNETOS REASSEMBLY Before reassembling, make sure that all parts are clean and free from chips or foreign particles. Front End Plate-Clean the distributor gear bearings thoroughly and then allow them to dry. Press the complete bearing and retainer into the side of the distributor gear hub nearest the front end plate side and also press in the outside race of the other bearing into the other side of the gear hub. Place the gear on the axle and install the orlglnal spacer and shlm washers and also the remaining cage and ball assembly. Secure gear with its plain washer and lock nuts. Do not greasethe bearings at this time as it is necessary to test the gear fbr end play. This is done by pressing on the outside diameter of the gear with the thumbs, first applying pressure on one side and then the other. If the end play is too great remove shim washers next to the spacer. The gear must turn freely with the least posslble end play. After the correct adjustment for end play has been made, remove the two lock nuts and take out the first cage and ball assembly. Pack Keystone No. 44 Grease into the hub of the gear around the axle. Reinstall the cage and ball assembly after packing it with Keystone No. 44 Grease. Reinstall the two lock nuts and then press on the brass cup after having placed a small amount of greasein it. Moisten all felt strips with oil. Rotatlng Magnet-There are two breaker cam keyways located on the cam pilot and two engraved marks on the rotatihg magnet back bearing plate, namely, "D" and "G". Place the cam key in the keyway opposite "D" for clockwise rotation and opposite "G" for counterclockwise rotation. Place the cam in position and secure it with its screw, lock washer, and plain washer.

rotating magnet away from its neutral position and then allowing the magnetic pull to return the rotating magnet to its neutral position. The neutral position of the rotating magnet is the position where one of the pole piecesfills the space between the top of the pole shoes which are integral with the magneto housing. The smaller the distance of the trailing edge of the pole piece from the top edge of the pole shoes, the tighter the bearings. The end play is too much if the distance from the trailing edge of the pole piece and the top edge of the pole shoe is more than fu" and too tight if less than /s". Adjustment of end play is obtained by placing steel spacing washers back of the inner ball races of the magnet shaft. These washers are available in thicknessesof .0025", .004",.005", .008", .0L0", and .012". If the inner races are removed, always keep the spacing washers which are already installed, in the same position. If additional washers are required to take up end play, install them equally in thickness in back of each inner ball race. If the original spacing washers are kept in place, it will be rarely necessary to adjust for magnet end play. Adjustlng Mesh of Dlstrlbutor Gears-It will be rarely necessaryto adjust the mesh of the gears if the position of the distributor gear axle has not been chahged. If a new gear is installed,

Charge the magnet in Magnet Charger No. 4-14215. Pack the ball bearings with Keystone No. 44 Greaseor its equivalent. Make sure that all chips or foreign particles have been removed from the magnet and the inside of the magneto housing. Place a light coating of oil on the pole piecesof the rotating magnet and insert the rotating magnet into the housing. Front End Plate, Rotatlng Magnet, and Ilouslng-Mesh the chamfered tooth of the small distributor gear (see Tolerance Chart) with the tooth on the large distributor gear marked "D" for clockwise rotation or "G" for counter-clockwise rotation. Secure the front end plate to the housing with its two screws and four lock nuts and washers. Adjustrnent of Magnet End Play-The rotating magnet should have no perceptible end play. Its adjustment is checked by turning the

TO ALIGN POINTS, USE SHIMS UNDER INSULATED . Fig. 1404

1406

MAGNETOS

however, it will be necessaryto adjust the mesh of the gears as described in the following paragraph. This is obtained by loosening the two screws and lock nut which hold the distributor gear axle to the front end plate. Turn the large gear until the round hole in the distributor gear axle flange can be seen through one of the holes in the face of the gear. Place a drift in the hole on the axle flange ind turn the flange slightly to the right to raise the large gear (loosen mesh) or to the left to lower large gear (tighten mesh). After adiustment is made, tighten and lock the two screws and nuts holding the distributor gear axle and apply Keystone No. 44 Grease or its equivalent ei""iy in ihe teeth of the large distributo-r gear. Dlstrlbutor Cyllnder and fnsulatlng PlateMake sure that the dog screw is tightened and in the face of the large locked in the hole located"D", gear marked for clockwise rotadistributor "G" for counter-clockwise rotation. tion. and The booster collector ring is secured to the diswith two screws. One screw tributor cylinder"D" and the other "G". The hole is marked "D" must face toward the straight hole marked line or timing mark on the distributor cylinder for counter-clockwise for clockwise rotation and"G" must face towards rotation the hole marked the str'aight line or timing mark. Place the distributor cylinder in position on the large distributor gear having the dog screw in the face of the gear engage a coruesponding hole located on the flat surface of the distributor cylinder and then install the lock ring. Install the insulating plate and the safety gap bridge to the magneto housing with their two seCuring screws. These screws must be staked after they have been tightened. Cotl-Place the felt pad between the pole shoe extensions in under the coil. Place coil in position and secure with its two screws, clamps, and washers. Make sure the high tension carbon brush is not broken or damaged while installing the coil. Breaker Assernbly-On the inside assembly are two tapped of the adaptor and stud "R" for clockwise rotation, holes, one marked "L" for counterfixed spark, and the other clockwise rotation, fixed spark. These holes are not used for variable spark requirements. MAGNETIC

The point assembly is secured to the breaker cup with two screws, plain washers, and lock washers. The eccentric screw protrudes through the slot provided in the of the point assembly. Install breaker assembly into the adaptor and stud assembly and secure with the two breaker hold down springs. Place breaker assembly in the full advance position by turning it as far as possible against the direction of normal rotation of the magneto. For fixed spark requirements, install clamp assembly or the collet which was used in earlier model magnetos, in the hole located inside the adaptor and stud assembly "R" for clockwise rotation and "L" for marked counter-clockwise rotation. plvotless type IMPORTANT-Sclnttlla contaet breakers as used ln thls serles magnetos must always be adjusted so that the s open at the proper posltlon of the breaker carn ln relatlon to the tlrnlng marks ln the rlrn of the breaker cup and not for any ffxed clearanoe between the s. Place a straight edge such as a steel scale (K) (see Fig. 1402, Tolerance Chart) on the step of the cam. Turn drive shaft slightly until the scale coincides with the timing marks (M) on the rim of the breaker cup. At this position, the points (C) should just begin to open. To make this adjustment, place a .001" shim stock between the cohtact points (C). Loosen the two screws (O) and adjust the eccentric screw (?) so that the points (C) just begin to open. The opening of the points can be checked with the .001" shim stock. When the .001" shim stock is releasedwith a slight pull, it indicates that the points are just beginning to open. Tighten the screws (O) and recheck adjustment. Apply a few drops of standard grade oil (S.A.E. 20 or 30) cn the cam follower felt. Do not give it all it will hold as excessoil will reach the points and cause interference with magneto operation. Secure breaker cover with its screw and safety pin. Maln Cover and Dlstrlbutor Blooks-'Secure the main cover with its two screws and install distributor blocks. Number discs are provided on top of the main cover in order that the distributor blocks can be installed on the correct side. AII felt strips on the main cover and front end plate should be made moist with oil.

AND DLECTRICAL TEST

Mount the magneto on Scintilla Test Stand No. 4-17011or an equivalent test stand. Connect the high tension cables to the 7 mm. three point spark rack. Run magneto for two or three minutes. Make sure that the rotating

magnet is not rubbing against the pole shoes of the housing. If so, this can be detected by the occurrence of a decided knock which must be eliminated by scraping out the inside of the housrng.

1407

MAGNETOS

ANTI-CLOCKWISE MAGNETO

ROTATION DETERMINE D FROM DRIVE END

cLoCKwrst MAGNETO

I V I E W E DF R O M I I B R E A K E RE N D I

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ADJUST POINTS TO .OI2 C L E A R A N C E . W I T H B R E A K E RI N F U I L ADVANCE POSITION, POINTS MUST BEGIN TO OPEN WHEN TIMING qBX MARKS IAII & COINCIDEOR WHEN ROTATING MAGNET IS 50 TO 90 PAST NEUTRAL,

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Fig. 1405

Check the coming-in speed with the breaker in the full advance position. It should spark consistently at 1ii5 R. P. M. If a variable spark magneto is being tested, also check the coming-in speed with the breaker in full retard position at which position sparks should occur consistently at250 R. P. M. Increase the speed to 3000 R. P. M. Observe the spark closely. If missing occurs, it may be causedby: Improper breaker adjustment. Dirty points. Faulty or broken connections. Defective coil. Defective condenser (if s arc excessively). Check the ground connection. No spark should occur at the spark rack if the magneto is short-circuited through the ground wire terminal screw. Connect the cable from the source of booster current to the booster connection in the magneto. Run the magneto at 500 R. P. M. and observe the booster spark at the spark rack. The booster spark always trails the secondary spark. Rotatlng Magnet-Operate magneto for about five minutes at 3500 R. P. M. During this run, short circuit the primary current at least 35

times. Then operate magneto at 400 R. P. M. (This speedmust not vary more than 10 R. P. M.) Hold points open by inserting a piece of insulating material between them. Connect Scintilla Ammeter No. 4-46762 in parullel or across the open points. The ammeter should not read below 1.8 amperes. If reading is below 1.8 amperes, the rotating magnet must be recharged in Scintilla Magnet Charger No. 4-142L5. Repeat ammeter test. If reading is still below, repeat test with a new coil before rejecting the magnet. Cotl-Before installing the coil in the magneto, check the resistance of the secondary winding with the No. 4-12933Y Ohmmeter. The reading must be from 4000-6000ohms. The final test of a coil must be made an actual running test of the magneto on the test bench. Also, as heat from the engine affects the insulation materials of the coil, the final test should be made at an elevated temperature. This is done by directing a reflector type heater on the magneto while it is being run on the test bench. When the temperature of the coil has reached approximately 165" F. (74'C.) the spark gaps should be increased by means of the No. 4-8386 Adjustable from 7 mm. to 9 mm. The coil must spark consistently at this temperature and spark gap. Increase the gaps to 10 mm. If

1408

MAGNETOS FIBER STOP CTEARANCE MUST BE .OO2 TO .OrO WHEN POINTSARE WIDE OPEN.

TENSfONt6-3 2 c 2. # 4-9713.) POINT C L E A R A N C E .OIO MINIMUM .OI2 DESIRED .OI4 MAXIMUM.

STAKE SCREW IN BREAKER LEVER.

KEEP FELT WICK MOISTW|TH OtL.

GAM MUST RUN TRUE WITHIN .OO2FULL INDICATORRFADING. CGAUGE 8 4-9886) Fig. 1406

consistent sparking occurred with the 9 mm. gap, intermittent missing with the 10 mm. gap will not be sufficient cause to reject the coil. It may be found that the coil produces consistent sparking at room temperature with 7 mm. gaps, however, if the coil does not spark consistently at the elevated temperature with 9 mm. gaps, it should not be used for further service.

Prhnary Clrcult Condenser-The condenser must be tested before it is installed on the magneto. The recommended test is made at an elevated temperature with the No. 4-L7-49, four hundred volt D.C. megger. The condenser must be heated to 200" F. (93" C.) in an oven. If the reading of the megger for the condenser at 200oF. (93" C.) is 50,000 ohms or more, the condenser is satisfactorv for further service.

VAGg.D AND VAGO.DR MAGNETOS This section is issued as a supplement to the SB9R magneto instructions and covers the servicing of the VAG9-DR magneto which employs a lever type breaker. AII instructions given in the preceding pages of this book which cover the SB9R magneto apply also to the VAG9-DR magneto with the exception of the breaker instructions. This section will cover the instructions for the lever type breaker. For VAG9-DR magnetos, the cross-section view of the lever type breaker as shown in Fig. 1404 replaces section A-A of the No. L0-1.5574 Tolerance Chart. Fig. 1405 shows the internal timing for VAG9-DR magnetos, clockwise and counter-clockwise rotation. AII other information on the No. L0-15574Tolerance Chart applies to VAG9-DR magnetos.

For general information, when the No. 2-792 high output Cobalt Magnet is installed in the "VAG9-D" magnetos which originally employed a chrome magnet, the letter rrR" is added, automatically making the type designation "VAG9DR". When checking the coming-in speeds or primary current values on "VAG" magnetos, make sure the values for the type magnet employed are used. The values when using the No. 2-792 Cobalt Magnet are given in the No. L0-15574Tolerance Chart. For "VAG" magnetos in service which employ a chrome magnet, the minimum primary current value is I20 R. P. M. and for full retard 240F". P. M. Lever Type Breaker Assernbly AdjustmentBefore installing the coil, place breaker assembly temporarily in the magneto for final adjustment.

1409

MAGNETOS Set the points with the Scintilla Wrench No. 4-490 so that the clearance between them is .012" as measured with the feeler gase on the No. 4-490 Wrench. With this adjuitLrent, the clearance between the back of the breaker arm and the fibre stop should be from .002" to .010" when the points are wide open. Check this fibre stop clearance for each cam lobe. Turn the magneto drive shaft until timing marks "A" and "B" (Fig. 1405) are approximately opposite each other. Place the breaker assembly in the full advance position. Turn the

drive shaft in the direction of rotation until the points begin to open. The points should open when the timing marks "A" an4 "3" are opposite each other or when the rotating magnet is 5" to 9o past its neutral position as measured with the Scintilla Timing Disc No. 4-25L2. After adjustment is made, remove breaker assembly and install the coil, main cover, distributor blocks, etc. Reinstall breaker assembly. Other information pertaining to lever type breakersis given in Fig. 1406.

1410

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CEAPTER XIV (Conflnued)

SERVICE INSTRUCTION FOR AMERICAN BOSCE AVIATION MAGNETO SB9RU.S GENERAL CONSTRUCTION Note-The numbers given in the following palagraphs are reference numbers onlyl referring to reference drawings contain6d in this instruction, and shouldnot be used when ordering service parts.

impregnated directly on its laminated core. This method permits more copper and insulating material for a _givelrspace ahd materially conl tributes toward reducing the temperatuie rise of the coil.

General Desorlptlon-The American Bosch SB9RU-3 is -a 9-c-ylinde_r,fixed-ignition, 4-pole, b-ase-mounted,.polar inductor type magnetb oi' clockwise-rotation, faqing drive eh-d,being driven directly through a qpli4ed drive coupling. The magneto drive shaf,t-which turns at- Lrfi engsne speed rotates the g-lobe compensatine breiker cam at one-half engine speed througf, a 2fu:t gear ratio between the inductor rotor and'distributor gear shafts. This magneto is completely radio-shielded, and includine radio shield and .coupling driven member, weighs LE% pounds.

_- The primary cable (83) goesfrom the terminal block (11) through slots in- insulation apron (b0) 3ng CgqI hoûsing.(46) to the assembly Tastening bolt (79) of the breaker plate, to wliich is ab5 connected the moving. and live breaker spring with point (78). The circuit between the second ary coil terminal (10) and the distributor roror is established -by. lraving the concentricallympgnted.,.round, high-tens-ion terminal post (1b) of the coil protrude into the rotating, ring-shaped electrode of the distributg,r rotor (b2). No physical is made. The circuit is estab'lisLed by a rotary jump spark.

magneto housing $."gleg.to Houslng (l)-The (!) is.die-cast, the material being fhigh-pressure aluminum alloy.

Frea\er Assenlbly (?0)-!he is stationary and consists of:

(M) are cast integral .Two stationary m_a_gnetq withpole shoe assemblies(P and Pr) and magneto -alloy housing. Tttpy ut" made from a special 'Alnico', known as the main charaiteristics of which are maximum available enersy and mini-helds, mum demagnetilation by stray high temperatures and mechanical vibrations. Inductor Rotor (5a)-The inductor rotor consists of a single laminated, 1*s.pole section mounle-d axially on the drive shaft *trictr is supporJe{ !y a 17 mm, one-piece, single-plate, senisealed ball bearing (7) on drive end-with a demouatable- one-piece oil seal packing (6) ing hub of drive coupling in front of briaring.

breaker assembly

a. 4r.adjlstable bracket (76), carrying the grouTded- -platinum-iridium breaker foini, is positioned betwedn.guidgqon breaker piate (20). This bracket is adjustable by means of an e6ce_ntrically-headedstud (75) and is secured after adjustment by a fillister head screw (g2). . b. A pjvoted cam follower a*sembly (?B) whose independent spring (74) maintains prbper iension of follower block against contour bf globe cam (31).

+\2 mm, siirgle-plate, semi-sealedball bearing (11) is mounted in gear housing to the inductor rotor at that end. The beaiing (Z) on the drive end is held in a fixed positiory thereby preventing axial movement of tlie inductor rotor. The bearinC eq on the other end floats in the gear hgusing and the outer raceway is.^lept_from . turning by _the retaining spring (43). The drive shaft end is splined to ac'commodate a splined drive couplins (2) which is secured with a recessed plain wishei 1B;, lock washer (4), castle nut (5) and cotter pin (58).

c. A br_eaker spring assembly (28), incorporating the moving and live platinum-iridium breaker point, is mounted on one side of an insulated terminal post by means of an assembly fastening bolt (79). To other side of terminal post, ove-r threaded end of fastening bolt, are connected.the prima,ry'cable (83) of tf,e coil, Iive s.ideof prqnary condenser (85), ing irlate (82).and short-circuiting spring (81). Tlie-ing plate (82) establishes with the grounding terminal assembly throueh a shortcircuiting spring (81). If for anv-reason the grounding terminal should become iemoved. this .564-cilcuitin^g spri-ng will ground the magneto against inner fae.-eof gear housing, thus acting as an automatic safety device.

Coll Assembly (O)-The high-tension coil with laminated core is mounted on the extension of the upper pole shoes. It is of a design wherein the primary and secondary are wound, taped and

Dlstrlbutor Bloek ( l9)-Distributor block (19) is of one-piece molded construction, made oi heat-resistin_gcomposition. Stainless bteel piercing screws (20) are used to secure all high-tension

14L2

MAGNDTOS cables. The nine electrodes are molded as inserts into the distributor block. Dlstrlbutor Rotor (52)-Distributor rotor (52) is a heat-resisting composition molding having two main working distributing electrodes, two booster electrodes and a booster collector ring. Electrical between the distributor rotor electrodes and distributor block electrodes is made by jump spark. The two booster electrodes are used in connection with an outside high-tension ignition source for starting purposes. Booster Conductor (16)-The magneto is provided with a booster conductor which is separately mounted underneath the radio shield to the dustcover by means of two fastening screws (18). Electrical between the booster conductor and the booster collector ring, molded into nose of distributor rotor (52). is made bv jump spark. The booster collector ring is integrally connected to trailing booster electrodes which are molded as inserts in the distributor rotor. These electrodes are spaced at a certain angle f,ollowing ,the main working distributing electrodes to produce a retarded spark for starting the engine. The booster conductor cable is fastengd by a stainless steel piercing screw (17). An independent booster coil with battery arrangement or booster magneto may be used for startrng purposes.

Radlo Shteldtng, (f4)-In order to suppress disturbance caused by electrostatic waves radiated by the ignition system, entire magneto including primary circuit within the brealier housing-is completely enclosed in metal housings or radio shields. O-Lobe Corrrpensatlng Cam (31)-Due to a condition which is inherent in all radial engines of conventional master rod design, the trav-el of each piston, with the exception of the master rod piston, is a few degreeseither early or late in reIation to the crank pin. The g-lobe cam (31) used in the SB9RU-3 has lobes so spaced as to compensate for the irregular apgular position of each link rod in relation to the master rod. The cornpensated cam_ insures each cylinder firingwith its piston at the desired advance position. The distributor gear shaft is partially hollow, with the space thus provided icting is an oii reservoir. Oil is fed in minute quantities to the surface of the cam through an automatic meterips _device (0) located in the distributor gear shaft. After reaching the surface of the gear shaft, the oil travels through a small hole in the cam to the surface where it lubricates the area between the cam and follower block (73). Quantity of oil in reservoir (37) is sufficient io provide ample lubrication between major overhauls.

MAGNDTIC AND ELECTRICAL CIRCUITS (SeeElectrleal Dlagram) As the inductor rotor revolves, it provides alternate paths for the magnetic flux as illustrated. Thus, the flux will from the north pole of magnet Mt through lower pole shoe Pl, inductor rotor, upper pole shoe P3,coil core and back to the south pole of magnet Ml. This path is illustrated by solid line. As inductor rotor keeps turning, the direction ofthe flux flow through the coil core is reversed, the flux ing from the north pole of magnet M2, through lower pole shoe P2, inductor rotor, upper pole shoe Pa, coil core and back to the south pole of rnagn'et M2, this path being indicated bi.y dotted Iine.

flux reversals, as described above, induce a primary current which flows to the ground when the breaker points are closed. TO DISTRIBUTOR

polarity is assumed for illusNote-Magnetic trative purposes only, and is not necessarily as shown in actual magneto. OnIy one magnet at a time delivers flux to the coil circuit. As'the cycle is repeated, it can be seen from diagram that four flux reversals are provided per revolution of the inductor rotor. The number of flux reversals is equal to the number of magnetic poles in the magneto. One side of the coil primary is connected to the ground, wbile the other end is connected to 15s llve and moving breaker spring with poinf (78) bV means of the primary cable (83). The

Electrical Diagram

This flow of current stores energy in the magnetic circuit which is utilized to generate high

1413

MAGNETOS voltage in the secondary winding of the coil. The discharge of this high voltage in the secondarv winding, one side of which is also connected to'the ground, takes place through a closely coupled j*ttp spark connection from the hightensfon terminal post (10) to the distributor rotor, spark distribution to the then by regular l*"p electrodes of the distributor block. The circuit is completed through the high-tension cablss, and ground. Exact time of dissnark plues -is ?etermined by instant at which the charge Iobes of the compensating cam open the breaker points. TIMING

AND INSTALLATION

Correct internal timing of the magneto has or at the overbeen accomplished at the factory 'Reassembly of Maghaul shop (see chapter on neto') so that magneto is ready to be mounted to engine. Breaker point opening has been adiusted to .009"-.010". This corresponds 'E' gap of 3-3.5 mm (proper position of to an inductor rotor relative to pole shoe when spark occurs) at instant points begin to open on 11 cam lobe. Mountlng Magneto to Englne-Bring pistoq of #1 cylin-der to advance firing position required on compression stroke. (Refer to Chapter VI for details on how to obtain this position.) Remove the radio shield (14), dust cover (13) with booster conductor assembly, distributor block (19) and breaker cover (39). Turn magneto drive shaft in normal rotation, as indicated by arrow on cam, until 11 cam lobe is about to open the points. No. 1 cam lobe is marked by a red dot on the face of the cam. When facing magneto drive shaft end, this position can also be observed by the white mark on distributor gear (49) on side nearest coil and the white marli on red pad on inner face of gear housine (46). When these two points are in line, #1 lobe of cam is about to open s for fring of #1 cylinder. Determine exact breaker point opening by inserting a .001" feeler gauge between the points, or connect a timing light acrossthe points. Correct instant is reached when a slight pull releasesthe gauge, or timing light goes out. Hold cam in this position by either pressing finge-rs asainst the dfutributor gear (49) or holding the diive coupling- so that inductor rotor shaft (54) cannot turn. Now place the magneto on the mounting plate of the engine, using the mounting plate dowel guide for sliding the magneto toward the rubber coupling. The dowels fit into coffespondingholes in the mounting surface of the magneto. Tighten the latter securely to engine mounting plate by means of the necessary cap screws. If the pronis of the magneto coupling member (2) will not mesh with the slots in the rubber cou-

The switch cable makes electrical through the terminal assembly, short-circuiting spring (81), etc., with the primary cable and live breaker spring (78) which are fastened to the insulated mounting post (70A). When switch is in off position, the primary circuit is shortcircuited, thus preventing the building up of high voltage in the secondary winding of the coil. The primary condenser across the breaker points is essential to proper ignition, preventing arcing and prolonging the life of the breaker points.

OF MAGNETO TO DNGINN pling in the position first tried, remove the magneto from dowels and adjust the rubber coupling until a perfect mesh is achieved. Ftnal Tfunlng of Magneto to Englne-For synchronized sparks of both magnetos, both sets of points must open simultaneously. This is done in the following manner: With the engine in proper position, as described under paragraph'Mounting Magneto to Engine,' and both magnetos having been mounted as outlined, proceed as follows: Turn propeller in a clockwise direction (facing front of engine) until the breaker points have closed. Insert .001" feeler strips between the breaker points of both magnetos, or connect two timing lights across the two sets of points. Turn propeller in a counter-clockwise direction by very gradually jarring the propeller blade with the hand until a slight pull on the feeler strips releases them, or until both timing Iights go out. Both feeler strips should release at the same time and should require equal efforts of pull, or if timing lights are used, both lights must go out at the same instant. At these magneto. settings, the engine timing marks must regrsrcr. If the feeler strips or timing lights indicate that the two magnetos are not perfectly synchronized, then the exact position for the opening of the breaker s on the magneto, which does not coincide with the engine timing marks, must be adjusted accordingly. If it is desired to advance the timing, remove magneto from dowels and turn the rubber coupling one or two notches in a counter-clockwise direction. If necessary to retard the timing, remove magneto from dowels and turn the rubber coupling in a clockwise direction. After the two magnetos have thus been synchronized, retighten the mounting cap screws and secure them with safety wire. Connect high-tension cables. Spark plug cable for 1L cylinder is inserted in distributor block cable hole marked #1 and secured with

t4L4

MAGNETOS

cable piercing screw (20). Insert the cable for the cylinder next to fire, according to firing order. into distributor block cable hole marked #2, etc. Note that the numerals on the distributor block (19) indicate the firing sequence of the magneto only and must not be construed as the firing order of the engine.

Replace breaker cover (39), distributor block (19), dust cover (13) with booster conductor assembly and radio shield (14). When installing the latter, make certain that screws (69) holdinE radio shield to gear housing are tight'en6d befor6 screws (55) holding shield to dust cover are inserted.

DISASSEMBLY OF MAGNDTO (Relerence numbers apply to relerence drawlngs) To facilitate reassembly of the magneto, it is suggested that parts be laid on a clean bench or in a pan in the order in which they are disassembled. Radto Shteld (14)-1. Disconnect ignition harnesscoupling from radio shield elbow (15). 2. Remove two elbow hold-down screws (56). 3. Open radio shield assembly by withdrawing three screws (57). 4. Remove two fastening screws (69) holding radio shield to gear housing (46). Also remove two fastening screws (55) holding radio shield to dust cover (13). Withdraw halves of the assembly. Dust Cover (18) and Breaker Cover (80)Dust cover (13), including booster conductor assembly (16), can be taken off by removing two fastening screws (62). Disconnect booster cable by Ioosening cable piercing screw (17). Separate booster conductor from dust cover by withdrawing two screws (18). The breaker cover (39) can be taken off by removing two fastening nuts (68). Dlstrlbutor Block (I0)-Remove two distributor block fastening nuts (65). Lift block vertically, remove insulation plate (21) by hand and disconnect spark plug cables by loosening piercing screws (20). It is recommended that each cable be tagged to facilitate reassembly. Prepare magneto for removal from engine by unfastening lock spring (26), unscrewing slotted nut (24) and giving switch cable a slight pull which will allow insulation gland (25) and terminal (27), including terminal nut assembly (28), to be withdrawn completely. Magneto can now be taken from engine by removing cap screws holding magneto to engine mounting plate. Coll Assembly (9)*Loosen screw (12) in cable clamping block (11) on side of coil and disconnect the primary breaker cable (83). Remove coil by withdrawing coil hold-down screws (60 and 61). It is not necessaryto place a keeper acrosst the pole shoe extensions while the magneto is disassembled. The insulation plate (63) under coil and primary cable holding clip (53) should be removed at this time by withdrawing three screws (64).

Breaker Assembly (70)-Remove hexagon nut (34), using a 32" socket wrench. This can be accomplished by holding inductor rotor shaft stationary (thereby also holding distributor gear shaf! in a rigid position) by means of wrench TSE 5232 placed in position on the splined drive coupling (2). Timing collar (32) and sealing gasket (33) can be removed by hand. Removal of the hexagon nut exposes felt oil restrictor plug (35) which should be pulled out of distributoi gear shaft at this time. Remove three fastening screws (41) which secure breaker assembly 170) to gear housing. Entire breaker assembly can now be pulled out and disassembledinto its component parts which should be carefully inspected (see 'Inspection after Disassembly'). Withdraw breaker cam (31), Woodruff key 'from (36) and copper wdsher (3b) distributoi. gear shaft. Dlstrlbutor Rotor (52)-To remove distributor rotor from unit, withdraw both the rotor and apron fastening screws (51 and 66). Unfastening of the latter permits horizontal movement of apron. Rotor and apron must be withdrawn together. At this point, back-lash of gears should be measured with a suitable dial sauee. With inductor rotor held in a fixed posilion', back-lash as measured on periphery of teeth on distributor gear must not exceed .010", otherwise both the distributor gear and drive gear must be replaced. Gear Eoustng (46)-Remove four fastening nuts (67). Magnetos are provided with two slots between magneto and gear housing to permit prying the two housings apart by means of two screw drivers. On earlier models having no slots, tap edge of gear housing carefully with a rawhide mallet to separate the two housings. (On these models, do not pry with screw driver or similar tool.) To remove distributor gear shaft from gear housing, screw drift tool TSE 5225 on end of shaft until it bottoms. Place tool TSE 5248-1 on arbor plate and insert two pins TSF, 5248-2 in proper holes. Locatn gear housing assembly on these pins which are so spaced that they will

L4L5

MAGNETOS slide through the two holes in gear hub and will press against gear housing surface. With arbor ram pressing against drift TSE 5225, push entire Iength of distributor gear shaft through gear housing. Remove bearings (22 and 30) from gear housing by means of puller ST 452. Remove spacer (29), spring riilg (23) and outer bearing race locking key i40). Inductor Rotor Assernbly (ba)-To remove inductor rotor (54) from magneto housing (1), proceed as follows: 1. Remove cotter pin (58), castle nut (5), lock washer (4) and plain recessed washer (3). Splined drive coupling (2) can be loosened by means of wrench TSE 5232. 2. Remove ball bearing thrust plate (8) which contains oil seal (6) bv withdrawing four fastening screws (59). To facilitate removal, take two of these screws and insert them in the

two unused, threaded holes with which the thrust plate is provided. Tightening of the two screws will provide the equivalent of a puller, and will withdraw thrust plate from magneto housing. 3. Inductor rotor is removed by screwing drift tool TSE 5225 firmly on rotor shaft and tapping end of drift with rawhide mallet. 4. Place tool TSE 5248-t on arbor plate in such a manner that there is free space below the slot in this tool. Slide rotor shaft into slot which is so shaped that it will just clear steel washer (48) on rotor, with seating surface pressed against insulation plate (47). Using pressing tool TSE 5248-9on shaft end, press shaftthrough ball bearing (44), rotor gear (45) and insulation plate. Now remove Woodruff key (42) and steel washer (48). Magneto Eouslng (l)-Tap out ball bearing (7) bV meansof a fibre rod.

INSPECTION AFTER DISASSEMBLY Metal Parts-All metal parts must be washed in clean gasoline and dried with compressed air. AII parts must be free from chips and foreign material. Examine magneto housing (1), gear housing (46), radio shield (14) and dust cover (13) for cracks, Ioose inserts and studs. Inspect all tapped holes. insulations, such as distributor Insulatlons-All block (19), distributor rotor (52), booster conductor (16), apron (50), insulation plates (2L, 47 and 63), coil (9), insulation bushings and washers must be cleaned with oily cloth and wiped dry with a clean cloth. Carbon deposits on distributor block and distributor rotor electrodes should be removed and electrodes cleaned with fine emery cloth. Distributor block and booster conductor cable holes should be examined and cleaned. Inspect assembliesfor cracks. coil for cracked end Coll Assembly-Examine plates and check soldered connections. Before of secondary ieinstalling coil, check continuity 'Testing and Perwinding as outlined under formance.' Ball Bearlngs and Otl Seal-All ball bearings must be cleaned in an approved solution and rough, loose or worn bearings replaced. Pack bearings with high-temperature grease American Bosch US 508 (or, if preferred, use Royco #5 grease). If oil seal (6) shows evidence of excessive 'Reaswear or leakage, it must be replaced. See procedure. Magneto' for sembly of the Gears-Examine both distributor gear assembly and rotor gear for butrs, excessivewear or other defects. Clean oil reservoir (37) in distributor gear shaft with approved cleaning solution. Breaker Assernbly (See Flgures I and 2)ThorougNy inspect and clean all component

parts of the breaker assembly (70). If the bakelized linen cam follower block is worn, replace with new lever assembly (73). Wipe primary condenser (85) with clean cloth dipped in clean machine oil and test condenser as outlined under 'Testing and Performance.' 1. I)resslng of Breaker Polnts: a. Examine both breaker points for evidence of wear. Extrbme care must be exercised in dressing points to insure a flat, square surface. Peaks appearing on surface of points should be removed, but it is not necessary to remove enough of the platinum-iridium points to cause small pits or craters to disappear completely, unless they collectively cover an excessive part of the surface. TooI TSE 5229 must be used for this purpose. 2. Reassernbly of Breaker (See Ftg. 1): a. Place breaker plate (70) on breaker assembly fixture TSE 5220 and secure by means of three fastening screws (41), lock washers and plain washers. b. Mount bracket with point (76) and secure to plate (70) by inserting screw (92) and lock washer (93) through cup-shaped bracket stop bushing (77). As bracket wiII have to be moved again, do not tighten screw (92) too securely. c. Assemble to fastening bolt (79), the following: Iock washer (80), spacing washer (88), spring with point (78), spacing washer (88), three shims (89), insulation bushing (90). Assemble these parts to ing post (70A). Over threaded end of fastening bolt (79), slide insulation bushing (90) and secwely tighten assembly to ing post by means of square nut (91).

t4L6

MAGNDTOS

Fig.t

SECTION A.A

d. FiU groove in cam follower lever ing post with high-temperature grease,American Bosch US 508. (Do not use Royco 15 grease.) Assemble cam follower (73) with follower block resting on flat part of dummy cam, and secure by means of plain washer (71) and cotter pin (72). Assemble follower lever spring (74). Make certain that plain washer (71) is not clamped between cam follower and cotter pin, but is perfectly free to turn. 3. Breaker Polnt Adiustrnent: a. Shift bracket with point (76) in its elongated hole until both points are in perfect alignment. Tighten screw (92) enough to hold bracket in place. b. Turn dummy cam so that cam follower block will rest on high part of cam. Loosen screw (92) and move bracket with point (76) bv means of the eccentrically-headed stud (75), until feeler gauge TSE 5213, inserted between the points, just becomesfree, indicating a point opening of .009"-.01,0". Tighten fillister head screw (92) securely. c. Check tension of spring with point (78), using spring scale TSE 52L2 (se Fig. 1). Hook of scale must be held adjacent to point as shown in illustration. Spring tension must be

Fig.2

S E C T I O NB . B

22-32 ounces at instant breaker points open. This can be determined by inserting a .001" feeler gauge between points. When a slight pull releasesthe feeler gauge, points are just beginning to open. A suitable electrical timing light connected across points may be used in place of the feeler gaugefor determining correct instant. For spring tension above 32 ounces, decrease by adding one shim (89); for spring tension below 22 ounces,increase tension by removing one shim (89). In adding or removing a shim, all parts on assembly fastening bolt (79) must be removed from ing post (70A) and reassembled in 'c' their proper sequence, outlined in section 'Reassembly of Breaker.' Readjust conunder 'a' and 'b' tact points as outlined in sections and recheck spring tension. d. Check cam follower lever spring tension using spring scale TSE 5212 (see Fig. 2). Tension must be t4-22 ounces at instant top of cam. follower block touches spring with point, otherwise lever spring must be replaced. e. Using feeler gauge TSE 5213, check clearance between top of cam follower block and spring with point (78). This must not be Iess thari .017" when follower is at its lowest position.

MAGNDTOS 4. Corrpletlng the Assernbly of Breaker: a. Fasten condenser (85) to breaker plate (70) by means of two fastening screws (86) and lock washers(87). b. Assemble ing plate (82), shortcircuiting spring (81), primary cable (83) and

r4L7

condenserlead on fastening bolt (79), and secure nut (84), using tool TSE 5218. The breaker assembly (70) should be removed from the breaker assembly fixture TSE 5220 and is then ready for ir?stallation on magneto. (See 'Reassembly of Magneto.')

REASSEMBLY OF TEE MAGNETO (See Reference Drawlng) Magneto Eouslng (1) and Inductor Rotor (54)-Insert post TSE 5248-3 in hole 'C' of tool 'fSE 5248-l-. Place round plate TSE 5248-4 on end of post. Slide magneto housing (1) over plate TSE 5248-4, which fits into the tunnel between the pole shoes. With sealed end of bearing facing the insjde of magneto housing, press bearing (7) into housing with large end of tool TSE 5248-8until it seats firmly. baII bearings must be packed with Note-All American Bosch US 508 grease or, if preferred, Royco 15 greasemay be used. Next, insert drive end of inductor rotor into hole 'C' of tool TSE 5248-1 which is placed on arbor plate so that free space exists b-elow hole 'C'. Assemble steel washer (48), Woodruff key (42) and insulation plate (47) on gear end of inductor rotor shaft. Using tool TSE 5248-6, press drive gear into place, with flat surface of gear resting against insulation plate. Care must be taken that keyway in drive gear lines up with Woodruff key. With sealedend of bearin9 G4) facing 4rive gear, press bearing on inductor rotor shaft with tool TSE 5248-7. Next, insert pressing tool TSE 5248-7 tnto hole 'D' of plate TSE 5248-1. Place inductor rotor shaft in an upright position by putting bearing (44) into the recess of tool TSE 5248-7. Slide magneto housing over drive end of shaft as far as it will go. Using large end of tool TSE 5248-8 on ball bearing (7) in magneto housing, press housing on shaft until bearing seats on shoulder ofinductor rotor shaft. If old oil seal is worn or shows signs of leakage, replace as follows: Place thrust plite (8) in h5le 'A' of tool TSE 5248-l and use small end of tool TSE 5248-5 for pressing out worn seal. Now turn thrust plate over and place it in hole 'B' of tool TSE 5248-1. Metal-ed side of new seal must face toward inside of magneto when thrust plate is irrstalled. Use large end of tool TSE 5248-5 to press seal into place, making certain that seal is properly seated iir thrusT plate. Assemble thrust plate with oil seal in magneto hogsi4g, using four screws (59). Tighten screws gradually and evenly, and stake screw heads with tool TSE 5219. Gear Eouslng Asserrrbfv (48)-Before assembling distributor gear shaft to magneto housing, oil reservoir (37) in shaft must be refilled with oil. This must be done in the following manner:

1. Fill oil pressure gun TSE 5233 with Fiske BS bearing oil, with oil at a temperature of about L20 to 130 degreesF. 2. With distributor gear shaft preheated to about L20 to 130 degrees F., fiIl oii reservoir to top of shaft, keeping spout of pressure gun under surface of oil to prevent air bubble formations. 3. Insert felt restrictor plus (35) into end of shaft and press firmly into plaie by hand until a paximym gf t4u" of-the plug remains protruding from the shaft. Elevated oil tempeiature wili prevent e-xcessive_ back-pressure of oil when plug is. pressed into shaft,- and prevents trapping oT air bubbles at head of plug.Note-If inspection after 'Testing and Performance' indicates either- insufficient or excessivecam lubrication after the oil reservoir was properly filled, as outlined above, and after inspection shows that the small oil hole from the center to the surface of the cam is not clossed up in the case of in'sufficient lubricatlon. then the entire distributor gear assemblv should be returned to the factorv for repiacement of the automatic metering oiler assembly (0). Under no circumstances should acijustment_ gt tttis assembly be attempted, nor should it be tampered with IN ANY WAY. A thin oil film on cam indicates that oiler is working properly. Mount outer bearing race locking key (40) in slot in gear housing (46) and s-ecure i'ittr spring ring (23). It is suggested that location of locking Fgy U" marked on the two hubs of gear housing-with pencil marks to facilitate assembly of bearings into housing. Locate gear housing assemb_ly,with breaker end facing upward, on tool TSE 5248-L0. With open siiie of bearing faging downward and one of its two slots aligneii with. pencil _marks,press bearing (30) into gear housing with small end of tool TSE 52[g-9. Bearing slot must, be aligned with end of locking Turn gear housing over so that gear side \"y. faces upward, with bearing which has iust been pressed in resting on slight projection of surface on tool TSE 5248-10. Ipse{ spqggl (29) which is held in place by tool- pilot TSq 5248-11. Press bearing (:2i) in- place as-oqtlined above, with slot in Fearing 'Remove al.ignedwith key. pilot from tool TSE 5248-10 and re-locate gear housing on latter. Check location of spacef to make sure that it is

1418

MAGNDTOS Iined up with bearings. Now press distributor gear shaft through gear housing, using tool TSE 5248-6for pressing against hub ofgear. Mountlng Gear Ilouslng Assexnbly to Maggear housing partially neto Iloust^ns-Guids on to studs of magneto.housing. mesh distributor gear and drive Irnportant-To gear teeth properly in order to obtain correct internal timing of the magneto, make certain that distributor gear tooth, marked with white dot on gear side facing ball bearing in gear housing, will become meshed between two drive gear teeth marked with red lines (seereferencedrawing). It is advisable, but not absolutely necessary, to turn floating inductor rotor ball bearing (44) until the edgesof one of the two slots are lined up with two red marks on drive gear teeth. This will facilitate seating of bearing against bearing retaining spring (43) in gear housing, thereby avoiding undue pressure on retaining spring which results if bearing must locate itself. Gear teeth mesh can be noted through observation hole of gear housing on breaker side. A suggested check is to place pencil marks on top of the two drive gear teeth as well as on the rotor side of the distributor gear tooth having the white dot. This will permit observation of the setting from either side of the gear housing. After correct gear teeth mesh is obtained, use rawhide mallet to tap gear housing firmly against magneto housing. Secure with fastening nuts (67). Apply a little American Bosch US 508 grease, with fingers, on surface of distributor gear teeth. (Do not use Royco 15 grease.) Dlstrlbutor Rotor (52)-Reinstall apron (50) and distributor rotor (52) together. Do not fasten apron screws until distributor rotor is in its proper place over the gear hub. When apron and rotor are in proper position, secure apron and rotor fastening screws (66 and 51) firmly. Breaker Assernbly (70)-Fish primary lead (83) from breaker assembly (70) through hole in gear housing assembly and slots in apron. Mount breaker assembly to gear housing by using three fastening screws (41), Iock washeis and plain washers. Screws should be located approximately in the centers of the three slots, but should not be tightened firmly at this stage. -be Now install a temporary ground wire (to 'Testing removed after and Performance' run) by inserting terminal nut assembly (28), terminal (27), rubber insulation Q5), and securingslotted nut t24) with lock spring 126). Slide copper washer (38) over distributor gear shaft until it rests against bearing (30). Mount cam (31) with Woodruff key (36) and copper gasket (33) on shaft ofdistributor gear.

Irnportant-Un4er no circumstances is grease to be applied to cam. This- is to avoid clogging of the small oil hole which permits the Fiske BS bearing oil to reach the surface of the cam from the metering oiler assembly. A second objeition is the possibility of grease reaching the breaker points, thereby causing burning and pitting of the latter. Assemble timing collar (32), which fits into cam slots jn olre posjtion only, by pressing it into place by hand until it seats snugfu in tlie slots. Use wrench TSE 5232 on drive coupling (2) to prevent distributor gear shaft from turning and tighten hexagon nut (3!) firmly by applying an even pressure on 14" socket wrench. Turn magneto in normal direction, as indicated by arrow on cam until the cam follower (78) is in cam dwell preceding #1 cam lobe. Insert .0_01" feele1 gagge between breaker points. Place straight edge across step of timing-collar. Continue turning magneto in normal direction gntil 11 cam lobe just begins to open points, indicated when a slight pull releasei the feeler gauge. A suitable electrical timing light, connected acrossrpoints, may be used in-place of feeler gauge to determine this instant. At this setting, straight edge must Iine up with timi4g marks 'T' qr rim of gear housing. If this is not the case, loosen three fastening screws (41) and turn entire.breaker plate in its slots until correct-position is obtained. Now tighten screws (41) firmly- Check breaker point setting by inserting feeleq gauge TSE 52Lg (.009t blade) which should just become free when cam follower is on the highest point of 11 lobe. If feeler gauge indicates that breaker point gpening is.other than .009" to .010", then adjust by loosening screw (92) and moving coniact bracket with point (76) slightly, by means of eccentri!"ally-headedstud (75) until correct opening is obtained. Screw (92) must be tightened firmly after adjustment. Re-rnagnetlzatlon-This magneto is unusually stable in its magnetization and does not ordinarily require remagnetization during routine inspections or even complete disassembly. Remagnetization should not be attempted unless the primary current reading as obtained under 'Testing and Performance' is below 1.7 amperes, and then only with a magnetizing stand of ploper strength. If remagne_tizationis necessary, use magnetizing stand TSE 5210 1or equivalent). Ailapter plate TSE 5246-2, held to law TSE 5246-t by pilot pins, is designed to make with th-e two exposedchamfered lower pole shoe surfaces P when base of magneto housing is placed in it. Next, slide jaw TSE 5246-3 into space between pole shoe extensions until ls made with upper pole shoesPt.

MAGNETOS It is essential to remagnetize magneto in the s€rme magnetic direction as originally done, otherwise a complete reversal of the permanent magnets will be required, which might possibly be beyond the strength of the particular magnetizing stand available. Polarity can readily be determined by means of a com. The south pole of the magneto should always be placed against the north pole of the magnetizing stand. Polesof stand TSE 52L0 are marked'N' and 'S'. Apply two charges of four to five seconds duration each. It is suggested that inductor rotor be gtven a quarter turn between charges, in order to allow saturation of both magnets in turn. Now remove adapter'plate TSEr 5246-2 fiom jaw TSE 5246-1,and reverseposition ofjaw TSE 5246-3 on magnetizing stand pole. This will leave two straight jaw surfaces. Place jaw TSE 5246-l against bottom of magneto housing underneath lower pole shoes P, and jaw TSE 5246-3 across upper pole shoe extensions. With jaws held on same poles of magnetizirtg stand as before, apply two additional charses of four or five seconds duration. This time;f charging will be sufficient to allow magnetizing current to build up to its full value for saturation of the magnetic circuit. Completlng the Assernbly-Fasten insulation plate (63) and primary cable (83), held in place by holding clip (53), to magneto housing with screws (64). Mount coil (9) on pole shoe extensions, with high-tension electrode inserted into distributor rotor. Place one plain washer under insulation washer and insert both in space between coil core and primary lead clamp assembly. Assemblelock washer, plain washer and insulation bushing on screw (60), and fasten coil to pole shoe extensions, using short screw (61) with lock washer to tighten right-hand side of coil (as seen from drive end of magneto). Connect primary cable (83) to terminal block of coil.

1419

After providing distributor block with temporary test cables, install insulation plate (21) by hand. Mount distributor block to magneto frame and securewith fastening nuts (65). Oheck air gap between electrodesofdistributor rotor and electrodes of distributor block with gauge TSE 52L4. At overhaul stage, with magneto being prepared for re-installation on engine, air gap between electrodes should not be less than .015" nor greater than .060". If the latter condition should exist, distributor rotor must be replaced. In cases where visual inspection indicates that distributor block electrodes are also worn or burned excessively, both distributor rotor and distributor block should be replaced. At this time, magneto should be tested as outIined under'Electrical Testing and Performance'. It is now assumedthat tests are completed with temporary ground wire and testing cables removed, distributor block reinstalled, and primary cable connected to terminal block of coil. Complete assembly as follows: Securedust cover (13), including the booster assembly (16), to magneto housing with screws (62). Fasten breaker cover (39) to gear housing with nuts (68). Assemble radio shield (14) and secure with screws (69 and 55). Note-Screws (69) holding shield to gear housing must be tightened before screws (55) holding rihield to dust cover are inserted. Mount radio shield elbow to radio shield. using screws (56). Assemble drive coupling (2), plain recessed washer (3), lock washer (4), castle nut (5), and cotter pin (58) to the drive end ofinductor rotor shaft. . Magneto is now ready for re-installation on engrne.

ELECTRICAL TESTING AND PERFORMANCE Condenser (85)-Test primary condenser (85) on a 500-volt Megger tester, with condenser preheated in an oven to 180-200degreesF. Ifreading is 1 megohm or more, condenseris satisfactory for further use. TERMINAL

VOLTMETER

Cott (0)-Check continuity of secondary winding by connecting coil in series with battery and

sensitive voltmeter of suitable range for battery being used (seesketch). A definite voltmeter reading must be obtained which will be somewhat less than the batterv voltage, depending on sensitivity of voltmetei. If continuity of secondary winding is checked with an ohm-meter, resistance should be 3900 to 4300 ohms. Final test of coil must be made during actual test run of magneto as outlined in latter part of this chapter. Test Runs-Attach pulley TSE 5250 to rotor shaft and mount magneto on a suitable test stand which is provided with adiustable test gaps ST 260. Test stand must have a variable speed range up to 3000magneto R.P.M. Connect high-tension cables to test gaps with pointed, three-electrode test gaps set at 9 mm (see sketch).

1420

MAGNETOS After remagnetization, operate magneto for 30 minutes at 2000 R.P.M. magneto drive shaft speed. While running, short-circuit the magneto primary fifty times in rapid successionby means of the grounding terminal, in order to reduce rnagnetization to a stable value. SPARK GAP AS REQUIRED

HIGH TENSION ELECTRODE

GROUND ELECTRODE MAINTAIN SHARP POINTS

After stablIization, magneto must be capable of firing the 9 mm test gaps without missing between L25 and 3000 R.P.M. magneto drive shaft speed. The magnetic strength of the stationary magnets (M) is tested by measuring the primary current output. To accomplish this, disconnect primary lead (83) from terminal block (11) on brimary side of coil. Connect one lead from high-grade AC ammeter, such as Weston Model 528 (0 to 2.5 ampere scale), or equivalent, to coil terminal block, and ground the other lead from ammeter to the magneto frame (stud on gear housing may be used as a convenient ground). If th€ magneto is properly magnetized and the electrical performance of the coil is satisfactory (seetest run for coil below), a minimum reading of 1.7 amperes will be obtained at 400 R.P.M. magneto drive shaft speed. If this reading is lower than L.7 amperes, the magnetizing stand should be checked by investigating battery condition and battery interconnecting leads. If battery is in good condition and properly conROUTINE

INSPDCTION

lubrication is required beLubrlcatlon-No tween major overhaul periods. regular routine inspecBreaker Assembly-At tion periods, breaker cover (39) should be removed from gear housing (46), and the instant at which points start to open on ffl cam Iobe (indicated by red dot), should be checked. At this instant, a straight edge placed across step of timing collar (32) should coincide with ing marks 'T' on rim of gear housing. Permissible limits are/n" on either side of ing marks 'T'. If this checks, no adjustments need be made. However, should the straight edge fail to come within these limits at instant points on 11 cam lobe are about to open, then correct in following manner: Facing front of engine, turn propeller counterclockwise (thereby causing magneto distributor gear shaft to turn in normal direction as indicated by arrow on cam) until cam follower is in cam dwell preceding #1 cam lobe. Insert a .001" feeler gauge between points. Place

nected to the stand, the magneto should be correctly remagnetized as per instructions contained herein. In the event that the current reading is still b"l9* 1.7_amperes after this remagnelization, coil tests having previously proven same to be in proper working _condition, then the charger used is of insufficient strength to completely saturate the 'Alnico' 14qgne!s, and the proper magnetizing stand should be obtained. Reconnect primary lead (83) to coil terminal block (11). In order to check the insulation of the coil under the worst possible operatin'g conditions, heat magneto with refleCtor type of heater to a temperature of not less than 165 nor more than 190 degrees F., as measured on coil core. In this heated condition, magneto'must be' capable of firing not less than 10 mm, pointed, three-electrode test gaps without missing, at any "magnetir s_peedbetween 200 ana 3OOOR.P.M. drive shaft speed. If missing occurs, ctrecX. magneto with coil of known quality. Should this check show that missing occurs because of difficulties other than coil failure, then the cable connections, breaker point adjustment, distributor block and distribufor rotor-electrode clearance, and primary cu::rent output must be investigated. Booster Current-Run magneto at 100-200 R.P.M. magneto drive shaft speed with grounding terminal grounded and the hish-lension cable from booster tinit connected tb booster assembly terminal. Use 7 mm pointed, threeelectrode test gaps for checking spark of booster. Booster spark follows the magneto spark, which can be checked by disconnecting- grounding terminal intermittentlv. AND MAINTENANCE straight e4_geacross step of timing collar (32). Jar propeller in a counter-clockwise direction untr_l slrqSht edge just lines up with timing marks 'T' on rim of gear housing. Loosen ad-jr:stable- _bracket, locking screw (92), and shift bracket by means of eccentr-ii screw (75) lrntil points are in such a position- that the_slightest counter-clockwise jairing of the propeller will open the points. This in-stant is reached when a slight pull will release feeler gauge. When setting is correct, feeler gauge will become free just as straight edge coincides with timing marks when propeller is turned counterclockwise, indicating that points on fil cam lobe are just beginning to open.- Now make certain that locl
t427

THERMOCOUPLE CONNECTION

4 3

I 4 POLE, FIXED IGNITION, BASE-MOUNTED MAGNETO, DRIVEN AT 1116 ENGINE SPEED.

:ilI

AMERICAN BOSCHAVIATION MAGNETO TYPESB9RU.3 H IGH- TENSION

G R O U N D ( S W I T C H) C O N N E C T I O NT E R M I N A L

\--

COMPENSATING CAM TURNS AT r/2 ENGINE SPEEO.

RED DOT ON CAM I N D I C A T E S NO.I LOBE

46

\ G E A R RATIO = 2 r/4

I

STRAIGHT EDGE PLACEO ACROSS STEP OF TtMtNG COLLAR MUST COINCIDE WITH TIMING MARKS "T" WHEN POINTS START TO OPEN ON NO.I CAM LOBE. THIS WILL G I V E C O R R E C T" E " G A P . PERMISSIBLE LIMITS ARE I/3e" ON EITHER SIDE OF TIM ING MARKS " T".

ROTOR WORKING ELECTRODE FIRING NO.I CYL. WHEN MARKS ARE IN LINE AS SHOWN.

ASSEMBLE GEARS WITH TIMING MARKS IN LINE AS SHOWN.

\\ ll &

ECTION B-

1501

CEAPTDR XV RADIO SHIELDING PRATT AND WHITNEY TYPE General-The Pratt and Whitney Radio Shielding is made in two sections and consists of a front and rear manifold to which are attached braided conduits for spark plug leads. Braided conduits also connect the manifolds and the magneto shields. These parts are ed by union connections to facilitate the operations of disassembly, replacement and assembly.

The manifolds are a covering for the ignition system cables. They protect the ignition cables from wear and deterioration due to exposure, and prevent them from becoming saturated with oil. It is general practice to replace the ignition cables at the time of each engine overhaul. This will eliminate the possibility of weakened or defective cable being overlooked at inspection.

DISASSEMBLY There are two types of manifold to spark plug conduit assemblies. The separate elbow type has a detachable elbow which is secured to the flexible conduit by a union nut. The tntegral elbow type has the elbow soldered to the flexible conduit. Separate Elbow Type-To disassemble,remove the spark plug terminal sleeve,unscrew the union nuts at the elbows and remove elbows from the ends of the spark plug leads. Disassemble the braided conduits between the spark plug elbows and manifolds by unscrewing the union nuts at the manifolds. Elbow Type-The elbow soldered Integral connection should not be broken at the time of

periodic overhaul unless one of the details is damaged, in which case, the solder may be softened by applying a torch, enabling the parts to be separated. Periodic overhaul disassembly may be accomplished by removing the spark plug terminal sleeves and unscrewing union nuts at the manifolds. Remove the grommets from inside the union nuts on the spark plug to manifold braided conduit. Remove the cable fastening screws from the distributor blocks to disassemble the cables from these blocks. Disassemble the magneto elbow assembly from the braided conduit and the braided conduit from the manifolds by unscrewing the union nuts. Remove the ignition cable from the manifolds.

CLEANING The metal parts (manifold, conduit, elbows, etc.) may be cleaned by the process described in Chapter III. INSPECTION AII conduits should be given a careful visual inspection for any signs of breakage. Inspect manifolds for dents or other damage. ASSEMBLY The following table is given as a guide for replacing ignition wires:

L502

RADIO SEIELDING TABLES OF WIRE LENGTES IN INCEES Wasp Hl and El-G Equlpped wtth SBOR Magnetos No. of Distributor Block No. 1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9

Total Length Rear Front Manifold Manifold

37" 55" 66" 46" 32" 46" 59" 55" 40"

ot

51" 62" 75" 62" 50" Dt'

83" 73"

Wire Length from Rear Manifold to Left Magneto L8" L9" t7rh,, 18" L9" L7rk,,

t8%" 20,, L9"

Wire Length from Front Manifold to Right Magneto 32%" 3314" 32" 32%" 33rh,, 32" 33" 34rh,, 33rh,,

Equlpped wtth SBORU-B Magnetos No. of Distributor BIock No. 1 No.2 No.3 No.4 No.5 No.6 No. 7 No.8 No.9

Total Length

Front Manifold oo

49s2" 63r2" 7554" 62%" 5012,, 58V8" 8454" 73"

Rear Manifold 35" 5314" 67r2" 4654" 32Y2" 4611" 60V8" 5654" 40,,

Wire Length from Wire Length from Rear Manifold to Front Manifold to Right Magneto Left Magneto 30rh,, T6" 1714" 32r2" 33t2" L8Y4" 33T4" t854" 34" Ls%" 32Ya" L732" 347A" 2014" 36r4" 2ty6" 33rh,, L9"

Eornet D-G, Ez-G, and E8-G No. of Distributor Block No. 1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9

Total Length Rear Front Manifold Manifold 38" 59" 55" 53" 67" 63" 46" 77" 32" 65" 46" 52" 60" 59" 56" 85" 40" 72"

Wire Length from Rear Manifold to Left Magneto L8" L9"

17%" 18" 19,, 17Lh" Lgrk,' 20" 19"

Wire Length from Front Manifold to Right Magneto 34Lh" 35%" 34" 3412" 35rh,, 34" 35" 36%" 35%"

Wasp Jr. B' 82 and BB Equtpped wlth SBOR and SB0R (N) Magnetos No. of Distributor Block No. 1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9

Total Length Rear Front Manifold Manifold 3'1" 53" 55" 47" 66" 58" 'll" 46" 32" 58" 46" 46" 59" 53" 55" 92" 40" 66"

Wire Length from Wire Length from Rear Manifold to Front Manifold to Left Magneto Right Magneto lg" 29" 19,, 30" L7%" 28rh,, 18" 29" 79" 30"

r7%"

181h,,

20" L9"

28r2" 29%" 31" 30"

1503

RADIO SEIDLDING Equlpped wlth SBOR(N)-a Magnetos No. of Distributor Block No. 1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9

Total Length Front Rear Manifold Manifold 57" 39" 60" 55" 62" 67" '14" 45" 6L" 29" 47" 45" 54" 59" 81" 53" 69" 39"

Wire Length from Rear Manifold to Left Magneto

Wire Length from Front Manifold to Right Magneto

18" L9" L7rh,, 18" L9" 1714" L8%" 20" L9"

29" 30" 28%" 29" 30" 28%" 29r2" 3L" 30"

Equlpped wtth SBORU-B Magnetos

No. of Distributor Block No. 1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9

Total Length

Front Manifold oD"

4814" 63r/+" 74%" 6trh,, 47%" 55%" 82%" 69" DIMENSIONS

Waep Jr. Magneto to Rear Manifold Magneto to Front Manifold

Rear Manifold 37" 5332" 68Yr" 45%" zgrh,, 45%,"

5e%" 54%" 39"

Wire Length from Wire Length from Rear Manifold to Front Manifold to Left Magneto Right Magneto 20%" 33" 201h,, 33" L9" 3t%" L8rZ" 3L" 17%" 30" L8" 30%" L7rh,, 30" r8rh,, 31" gLrh,, t9"

OT FLDXIBLE CONDUITS I.D. Length (In Inches) (In Inches) lYn + \s l0%+%a L%z+ %a 2l%*46

o.D.

(In Inches) 1.335-1.345 1.335-1.345

Eornet E

27 Ya*. Xa

L0ryr6 + Yt6

Lrl + Yn Lr/a+ %a

l3%4 135/u

L0r%6+ N6 27%a*\a

L%+Xt L%+%t

Ls%4 L3%4

Magneto to Rear Manifold

l0rh+X6

r%

L3544

Magneto to Front Manifold Magneto to Rear Manifold

25 +X6 L2 rl * Yra

r%

L\Y6L

L%z

1.340-1.355

lYrz

1.340-1.355

Magneto to Rear Manifold Magneto to Front Manifold Eornet D2-G ond E8-G Mameto to Rear Manifold Magneto to Front Manifold Waep Hl

Large Dlameter Small Dlameter

Magneto to Front Manifold

LN6

1504

RADIO SHIELDING

For information pertaining to any ignition cable not in the following approved list, consult the Service Department of Pratt and Whitney Aircraft. Belden Manufacturing Conrpany Chicago, Illinois, General Cable Corporation Buffalo, New York, Packard Electric Division General Motors Corporation Warren, Ohio, Sterling Cable Corporation Port Huron, Michigan. Mark ferrules consecutively from 1 ihrough 9 with a suitable metal stamp. To reassemble, remove /2" insulation from the end of each lenglh of cable,-being careful not to cut any of the strands. Sepaiate -along the strands of wire and bend the insulation' Install each them back ferrule on its corresponding number ignition cable and secure it with a crimping tool. String the cables through the manifold and in their pr-operoutlet holes, maintaining the neces-

sary length of cable from manifold to magneto. Asiembl6 the spark plug conduits and fasten with union nuts using a grommet in each union. Install the elbows and terminal sleeves, and solder the ends of the wires to the terminal sleeves. Assemble the conduits from manifolds to magnetos. Using some form of standard electrical test, make sure that the number on each ferrule corresnonds with the number of the cylinder to which the cable runs. Then attach the wire to distributor blocks according to the the magneto -diagram wiring tFig. 611). After assembly of the niagneto block, again check with some form of standard electrical test to make sure that the wires are in position for proper firing order. AII ts should be carefully inspected after assembly to seethat they are snug and that there are no vibrating s. No external soldering should be attempted while the ignition cable is in the shield, as the heat necessaryto make the soldered t is detrimental to the insulation of the cable, and may injure it to the extent that this point will be the first to break down.

REPLACING ONE IGNITION Determine which cable is defective by a recognized electrical test. Disassemble the connection and elbow from the end of the spark plug lead and remove the spark plug lead conduit Ly uncoupling the union nut. Remove the wire from the distributor block. Loosen the coupling nut on the conduit from the manifold to magneto and slip the conduit back towards the distributor block. Solder the new cable to the old cable at the spark plug end. Dust the new cable with talc oi soapstone to prevent seizing or friction. Pull the old cable out, at the same time feeding the new cable in at the manifold. It is necessaryto perform this operation carefully so as not to injure the protective coating on the cable. When the new wire has been pulled through far enough, cut it off to the proper length on each end. Reassemble the conduits, elbow and spark plug terminal sleeve connection, and solder the wire to the connection.

CABLE

Termlnal Sleeves-Particular care should be exercised when installing the terminal sleeves on the ignition wire.' Cut only enough insulation from the conductor to permit the correct length of wire to extend through the wire outlet. Th6 insulation must bear firmli against the brass disc on the inside end of the sleeve. The ends of the ignition wires which are constructed with a layer-of cotton under the lacquered surface should be dipped in an insulating varnish to about y8" ;;d permitted to dry before the terminal sleeves are applied to the wire. This treatment prevents th6 layer of cotton from acting as a *ick should moisture find its way inlo the a-ssembly. When installing the terminal in the plug it- should be wiped- perfectly clean, and aftel that not touched by the fingers as oil, acid, dirt, etc., will promote flash-over, cause deterioration and eventual failure of the sleeve. The repeated installation of dirty sleeves in a spark plug results in contaminating t-he mica insulation-on the inside of the barrel, which eventually will cause faulty operation.

1601

CEAPTERXVI AUTOMATIC

OIL TEMPDRATURE CONTROL DESCRIPTION

A thermostatic oil temperature regulator is now included as standard equipment to be incorporated in the oil system of any airplane. This device automatically regulates the temperature of the oil entering the engine to a predetermined setting, thus obviating the use of radiator shutters or other means of controlling oil temperatures on a great number of installations. Where 8" coolers,or larger, are utilized, congealing ofoil mav occur in the core of the cooler if the amount of dold air is greatly in excessof that required for oil cooling. Obviously, under these conditions it is necessary to have shutters or some other acceptable means of controlling the amount of air albwed to flow through the-cooler. It,also reduces the warming up period to approximately one-half the time over installations not equipped with this device. When the oil is cold, the valve automatically directs the outlet oil from the engine to the bottom of the oil tank, in close proximity to the suction line. Consequently the warm oil coming from the engine will be drawn into the suction line feeding the oil pre$sure pump. This process continues until the oil entering the engine reachesthe desired temperature; at which time, the automatic valve directs sufficient oil through the plane's external air cooler, thence to the top of the oil tank to maintain the desired inlet temperature. The current type thermostatic oil temperature control assembly incorporates a check valve at the point where the engine return oil line connects to the unit. This valve prevents oil flowing from the tank into the scavenge system of the engine while the engine is not in operation. automatic oil temperature Malntenance-The control unit normally requires no attention between overhaul periods. The operating limits of the unit cannot be altered except by replacing the sylphon with one of a different calibration. the four nuts holding Dlsassembly-Remove the two bodies together and separate. Disassemble nut from the end of the thermostatic unit and unscrew unit from body. Also remove the two nuts holding the check valve housing from the body which housesthe valve and separate. The unit is now disassembled sufficiently for ordinary inspection. If, however, it is intended to replace any parts, remove the solder, nut and waslier on end of unit. Disassemble valve and

vhlve guide. IJnscrew pin holding the check valve bushings and springs in place. The springs, bushing and valve may be then removed through the slot in the top ofthe check valve housing. Cleanlng-Clean all parts with white furnace oil, or some suitable cleaner. Inspeatlon-The automatic oil temperature control unit should be inspected at every regular engrne overhaul period by checking clearances in accordance with clearance chart on Page 1603. Inspect the sylphon for any dents or cracks. Also inspect the seat of the check valve in casting. Assembly-Assemble valve guide and valve to the thermostatic unit. Fasten with washer and nut. Lock the nut with solder. Assemble gasket on each side of the valve guide and gasket on the threaded end of the thermostatic unit. Assemble unit in body and fasten with nut. Install body and fasten unit together with washers and nuts. Then assemble the check valve assembly by inserting the springs, bushing and valve through the slot at the tbp of the casting and insert the pin holding them in place. Therrnostatlo Unlt-It is good practice to test the thermostatic control at the time of overhaul to determine whether or not the thermostat bellows are properly actuating the valves at the desired temperature settings. Earlier units did not have any temperature settings recorded on the unit. Later units had the temperature settings on the thermostat stem only, while cunent units now have the settings stamped on both the thermostat stem and data plate. In the case of the earfier units, the temperature settings will have to be determined by checking the unit. The temperature ranges and Part Nos. of thermostats are as follows: Part No. 18199 1p198 18197 16403 11435

Range 85oto 105'F. 120oto 140'F. 140oto 160'F. 130oto 150'F. 150'to 170'F.

It should be noted that the above listed range temperatures are the temperatures at which the valve starts to open, and at which it is fully opened. The temperature at which the oil will stabilize is dependent upon the airplane installation.

1602

AUTOMATIC OIL TDMPERATURD CONTROL

BODY toNe cHAMBER)

UNIT THERMOSTATIC

CHECKVALVE HOUSING

VALVE GUIDE (TWO CHAMBERS)

Fig. 1601 -

Automatic Oil Temperature Control Unit

Oil should be circulated through the unit at the temperature of the lower setting. With continued operation at this temperature the valve should be just starting to open, although no oil should be allowed to through the outlet to which the oil cooler normally connects. Then with the oil at the temperature of the higher setting, the valve should move to and remain in the "oDen" position which will direct all of the oil thr6ugh the outlet to the cooler. Cheak Volve-The check valve and seat may be tested for leakage at the time of overhaul as follows: Subject the valve to 180 viscosity oil under a Dressureof 3 lb./sq. in. If the valve leaks in ex'cessof one ounce iri 2l hours, the faces of both the valve and the valve seat in the casting should be machined to obtain a perfect seat. The tension of the spring against the valve may also be checked by connecting a head of 180

"oil from pump" flange of the viscosity oil to the gravity assisting the valve to unit so that with open, the valve should not open with a 5" oil tiead'nor should remain closeil under a 30" oil head. Oll to Cooler Poeltlon-An added improvement "Three is now incorporated on the later type or Bolt Flange Type of lJnit", which provides for locking the unit so that all "Return Oil" frcm the engine is dfuected to the oil cooler. This feature, however, is only used in special flights to test oil cooler capacity. On satisfactory completion of the oil cooling test, the unit should be readjusted to operate automatically. To set the unit in "Oil To Cooler Position" loosen lock nut on the end of the Thermostatic Control Shaft and screw in shaft until it bottoms on the stop provided for this position. Tighten lock nut and safety with brass wire.

1603

AUTOMATIC OIL TEMPDRATIIRD CONTROL

J J

83a

t8B t() rn

JJ

69 qq () ()

'rl

J J

sEg (Yl(} ()

nllllllillh €k It

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Jt

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sggENt5 E 8 E 'j-,

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ooG' ar\ /

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ALT ITUDE CALIBRATION OF AUTOMATIC OIL TEMPERATURECONTROL SHOWINGDECREASEOF OIL TEMPERATUREWITH INCREASINGALTITUDE

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1701

CEAPTER XVII AUTOMATIC

MIXTURE

AND POWER CONTROL

UNIT

THDORY Due to the fact that the metering characteristics of a carburetor are a function of the air density entering the carburetor, a simple method of maintaining a constant metering characteristic is to maintain a constant density of this air. To do this one must either employ an external supercharger to maintain sea level density or an PRACTICAL To avoid the use of an external supercharger, the air density control valve method was chosen. The particular application under consideration for a-supercharged engine where it is desirable to restrict the maximum sea level power output, the two-fold purpose of the unit is readily comprehensible in that a reduction in the density of the air entering the carburetor to the density altitude at which full throttle operation is permitted not only serves as an automatic throttle stop, but at the same time gives the desired constancy of carburetor metering. Carrying this thought

air density control valve to maintain a density equivalent to a predetermined altitude. The use of such an air density control valve necessitates the reduction of the power output of the engine at all times to the full throttle power at the density altitude chosen. APPLICATION still further, there is a density altitude at which the full throttle power is reduced to what is considered the normal cruising power of the engine. If the air entering the carburetor be reduced to this density, the cruising power output of the engine will then be maintained from sea level to this altitude and the carburetor remain characteristics constant metering throughout this range. In either of the above cases, the carburetor throttle would be left in wide open position at all times.

DESICN OF UNIT To take care of cruising conditions, the unit must reculate to one pressure; to take care of conditiois requiring mbre power, the unit must regulate to a second presfture and for cases of emergency -the where it might be necessary to exrated power the air density control ceed

valve must be held wide open. (For the cruising condition one mixture ratio from the carburetor is deeired, while for the higher power a second mixture ratio is desired, and for the emergency full power condition, a third or still richer mixture is required.)

AUTOMATIC MIXTURD CONTROL UNIT The Automatic Mixture and Power Control Unit is a device for maintaining the air entering the carburetor at a constant pres€lrre, and openine the correct number of jets in the carburetor to grve the desired mixture strength. A special type carburetor is supplied with this unit in oi8er to obtain the aulomatic mixture control feature. Bellows regulate the air pressure control valve through an oil servo mechanism.

The unit is provided with a selector valve and three positions are available. . The normal throttle and manual mixture controls are provided on this carburetor in case of any malfunctioning of the Automatic unit, and the Automatic unit does not interfere with the normal It does, however, make it use of the throttle. possible to leave the throttle wide open for all normal flyrng conditions except landing.

EXPLAITATION OF TEE OPERATION OF AUTOMATIC MIXTIIRE CONTROL The operation of the automatic mixture control resuiator is shown diagrammatically on the followins pages. It will be seen from these illustratilons that the principal operating parts of the regulator consisl of two bellows, a lever arm actuited by any movement of the bellows and a needle valve directing oil to the two sides of the operating piston. Of the two bellows

one is evacuated and spring loaded internally, and the other vented behind the venturis in the carburetor, thereby being affected by the carburetor air horn pressure. If the absolute pressure in the air horn is such that the evacuated bellows is collapsed, the lever arm is drawn to that side and, being fixed at the top, draws the needle valve to that side. This action its

t702

AUTOMATIC MIXTURE AND POWER CONTROL UNIT

C a s ef i l ! i r r gC a p

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Oil Pressure Cottttectiolt

Open Bellows

"CruisiIg" Adjustine

Evacuated

" llid Prsitiorr" Pressurc u-.tirg Nut

Bellows

Sen o Needlc ()perating

Presstrre Nut

Yalse Lever Lock Nuts

Serlo

\'alre

Prcssure Yalvo Operating Piston Shaft

Oi! l)rsiD Fittinc

Carburetor Jet ),Ieedlistonr

Automatic Mixture Control Unit

engine oil pressure to the back of the operating piston at the same time opening the opposite end to drain, all of which forces the operating piston outward and through suitable linkages closes off the pressure control valves in the carburetor. As these valves are closing, the absolute pressurein the air horn is being reduced. When this pressure reachesa value such that the open bellows tends to collapse, thus expanding the evacuated bellows, the needle valve is thereby moved. During this movement, there comes a time when the needle valve is in its central position thus holding the operating piston and air valves stationary. The absolute pressure to which the unit regulates depends on the strength of the springs in the evacuated and open bellows. In this respect, it is readily. seel that an- increase in spring compression in the open bellows will change the absolute pressure for balance to a lower value. This feature is used to enable the same regulator to control the two different pressures and is accomplished by what is termed the range-shifter piston operating on the spring in the open bellows. Adjustable stop nuts are provided to limit the travel of the range-shifter piston in both directions thus providing an adjustment for both regulated pressures. The jet and age arrangement in the car-

buretor is shown diagrammatically in the illustrations on the following pages. For simplicity in explanation, let us consider the cruising position first. Here the regulator is set to maintain a pressure equivalent to an altitude of say, 11,500 feet. This means that the density in the carburetor is greatly reduced and on a normal carburetor would require the use of some mixture control. In this carburetor, two of the jets are selected to give the desired consumption at this altitude, and the other two being cut off due to the needle valve being closed. As the regulator will maintain a constant pressure in the carburetor, these two jets will give uniform metering at any altitude below the critical altitude. In the mid position (sometimes used as a higher power cruising position) the regulator is set to maintain a pressure equivalent to a somewhat lower altitude, say, 6000 feet. This necessitates additional fuel capacity in the carburetor due to the decrease in altitude and, becausehigher power is available from the engine, necessitates an even greater fuel consumption. To accomplish this, a third jet is brought into action by relieving the oil pressure holding the needle on its seat. In the emergency position (see Fig. 1701) where the regulator is inoperative and the air horn pressure is always atmospheric, additional


L707

ASSEMBLY 1. Put servo needle in its bushing and push through until hole for lever pin appears in cup rn case. 2. Assemble bellows with connecting spool. 3. Put bellows together into case with gaskets on each end. Assemble so evacuation tube on evacuated bellows is on opposite side from housing cover plate. 4. Install needle valve lever. Put half of lever with pin riveted to it on opposite side from evacuating tube. Be careful not to break this tube when putting other half of lever in place. Be sure discs on lever are in the spool of the bellows link and the upper fulcrum. Bolt parts together using lock washer under nuts. 5. Put operating piston in cylinder and screw on guide making sure gasket is assembled. 6. Assemble range-shifter piston guide and piston with adjusting nuts. 7. Put range-shifter piston in cylinder. A tool should be used to guide end of piston shaft

through oil seal in bottom of cylinder. The tool should be a rod of same diameter of oil seal with a pilot on end to fit in the range-shifter piston shaft. The return spring must be in place before piston is assembled in cylinder. 8. Push range-shifter spring thrust plate in end of shaft. 9. Drop range-shifter spring into bellows stop sleeve and over thrust plate. 10. Put selector valve in from drain fitting end, holding locating pin slot toward parting surface. Push in until slot with three drill point holes lines up with pin hole, then drop pin in place. 11. Place locating pin spring on top of pin. 12. Holding unit horizontally, press cylinder assembly into housing and bolt up securely. Be sure that locating pin spring goes into the hole provided for it in cylinder body. 13. In some cases,it is easier to assemble the drain fitting before assembling the two parts of the unit.

INSTALLATION The Automatic Unit is bolted to the rear of the carburetor, making oil pressure and drain Iines the only piping necessary. The pressure control valves must be at least 8" below the flange of the carburetor or on an elbow giving an equivalent distance in order not to spoil the m'etering characteristics of the carbureior. A suitable linkage must be supplied to connect these valves with the operating piston of the Automatic Unit. Any scoop design, other than those suggested by Pratt and Whitney Aircraft, should be sent to the carburetor manufacturer, to test its effects on metering characteristics. In installation, care must be exercised to see that the pressure control valves have a full 90o

travel, before the operating piston reaches its full stroke. Suitable oil pressure and drainage connections in accordance with the installation drawing should be provided. Besidesthe usual throttle and mixture controls, an additional control to the pilot's cockpit is required for the automatic mixture control regulator, although a combined control for the regulator and manual mixture may be used if desired. After installation on the carburetor, be sure the bellows caseis full of cylinder oil. This oil is poured through the cap on top of the case marked "Fill".

OPERATION When properly installed, the automatic mixture control operates in the following manner:

no economizer action. Proper use of the mixture control will give normal consumption.

in Errrergency Full Power Posltlon-When this position, the carburetor functions conventionally, being independent of the automatic unit. The air pressure control valve is held wide open both by a spring and servo control mechanism. All four jets in the carburetor are in use giving a full rich fuel consumption near full throttle that is normally experienced on a standard type carburetor. At a throttle position equivalent to the normal cruising R. P. M. the mixture is slightly richer than n6rmally experienced at this speed due to the fact that there is

Mld Posltlon-When in this position, the air pressure control valves are in operation, limiting the power to a predetermined valve and closing one jet to give the correct mixture strength for this power. By use of the engine throttle, less power than the maximum regulated by the unit can be obtained. Crulslng Posltlon-When the control is moved to this position, the air pressure control valve is maintaining a pressure below the carburetor which allows a predetermined power output

1708

AUTOMATIC MIXTURE AND POWNR CONTROL UNIT

desired for cruising. The second oil controlled jet is closed off leaving two jets in operation wtrictr gives a mixture ratio considered most practical with regard to economy and durability of the engine. This power and fuel consumption is maintained at aII altitudes below the critical cruising altitude or that altitude where cruising power is maintained only at full throttle. This

position is used only for normal cruising, and stroutd not be used for climbing. Even if the airplane is flown two or three thousand feet above the critical altitude of this position, the enrichment of the mixture will not be great enough to necessitate using the manual mixture control. By use of the engine throttle, Iesspower than the m'aximum regulited by the unit cin be obtained.

ADJUSTMENTS All adjustments are made on a unit when tested at the factory. Following the installation, a check on the operating pressure below the carburetor for the mid and cruising positions should be made. If these do not agree with the recommended pressures, something is undoubtedly wrong with the regulator unit. Only in TESTING AUTOMATIC

MIXTURE

Operatlon of Test Set-Up-Since the Auto--atic Mixture Regulator is- a pressure control device, means should be provided for setting this regulator to control to the desired pressure. Fig. 1704 shows a convenient set-up for adiustiig the regulator. As the pressuresto which the regulator is to be set are less than sea level atmospheric pressure, a source of vacuum is required. (In exceptional cases, where such a tesl device is located at a high altitude field, a source of pressure may have to be substituted.) An aspirator or vacuum pump may be used, as shown at (D), with a valve (C) to control the degree of vacuum. With a fixed air bleed (E), the pressure in the system depends on the rate of flow through this air bleed, and the pressure may be controlled by throttling with the petcock (B). This pressure is transferred to the automatic regulator and is recorded by the manometer (A). Connecting the petcock (B) to the operating piston rod of the automatic regulator, the petcock is automatically adjusted to-maintain the pressure for which the regulator

rare cases will a unit require readjustment and this should only be done by a specially trained mechanic. The carburetor is of the fixed jet type and the proper jet sizeshave been determined and tested in each carburetor. Under no circumstances should these be changed. RDGULATORS ON BENCII RIG is set, and this pressure is maintained with varying degreesof vacuum set by valve (C). Test Rlg for Automatlc Mkture and Power has been found that when a Control Unlts-It standard petcock valve (B) is used, it opens and closes too abruptly and does not provide a smooth increase or decreaseof vacuum necessary for the adjustment of the automatic unit. By reoperating a standard petcock valve, as shown in Fig. 1705, the desired straight line characteristic will be obtained in the opening and closing of the valve and prevent hunting. The dimensions contained in the sketch are approximate, as each valve will have to be reoperated to suit the test rig in which it is to be used. An appropriate method of reoperation is to file a small groove in the valve and then try it out in the test rig. The desired condition will be attained when the travel of the mercury in the manometer is smooth and gradual during the opening and closing of the valve.

ADJUSTING TEE AUTOMATIC For the purpose of clarity, the positions of the selector valve are given as follows: of selector valve Ernergency Posltlon-Position when unit is inoperative. Manual mixture control has to be used when necessary. of selector valve when Mtd Posttlon-Position unit is in operation, and used for take-off, climb or higher cruising power than normal Crulslng Posltlon-Position of selector valve when unit is in operation for normal cruising requirements.

REGULATOR

The absolute pressuresto which the regulator is to be set are determined from dynamometer test to obtain the desired engine power. The figures for these presriures are supplied with the regulators. Given the presswes, the regulators are adjusted on the test rig as follows: 1. BoIt the regulator securely to the mounting plate (H). 2. Connect the operating piston rod to the petcock (B).

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3. Connect the oil pressure line to the regulator, and after starting the oil pump, adjust the oil presriure to about 80 lbs., by means of valve (G).

is not correct, move the adjusting nuts on the regulator until the desired pressure is obtained. Do this for two positions of the selector valve - i.e., the cruising and mid positions.

4. Set the selector valve (F) in the position for which the pressure is to be checked (cruising or mid position). 5. Adjust the vacuum supply valve (C) until the operating piston has moved about half its stroke. 6. Read the manometer, and if the pressure

7. After obtaining the correct adjustment on the regulator, vary the amount of vacuum by the valve (C), and see that the regulator holds the pressure for which it was set. In this check, do not supply too much or too little vacuum, as it will cause the operating piston to hit the stops at the end of its stroke, and the manometer reading will not be correct.

GENERAL NOTES ON ADJUSTMENTS 1. If the absolute pressure is too high ("U" tube reading too low) move the adjusting nuts from the body of the regulator, and if too away -("(J" tube reading too high) move the nuts low toward the bodY. "Cruising" 2. The inner set of nuts are the "Mid" position adjustment and the outer set the iosition adjustment. 3. If full travel of either set of adjusting nuts fails to give the desired pressure, the fulcrum of CIIECKING

the servo valve lever may be moved. It must be ed when using this adjustment that rrMid" and "Cruising" adjustit affectsboth the ments by the same amount, making a readjustment.of one of them necessary. After moving the fulcrum be sure to check the adjustment of both positions. Also care should be taken that extreme adjustments of the fulcrum does not cause the unit to be sluggish in one direction (seefollowing paragraph).

OPERATING CIIARACTERISTICS

Slugglshness-Change vacuum rapidly and obselve speedwith which operating piston moves. The piston should move at approximately the same speed in both directions. If the movement is ver5rslow in one direction, the fulcrum adjust-ment-has been set to an extreme distance off far out center. If the fulcrum screw is set too"closing" the movement will be slow in the direction, and if set too far in it will be slow in "opening" direction. the Hotdtnc Pressure Under Load-Apply a load to the operating piston shaft by a spring (use tension spring and pull on it) and observe the reeulatins pressure with and without load. If th"eseare not the same, check the fit of the servo valve in the bushing. A loose valve will cause a variation in pressureunder load. Also this condition would indicate a slight leak between the servo valve bushing and the case, if the servo valve itself were tight (Fit of valve and bgqhittg is.0005 to.0025 loose). The pressureshould not vary more than .1 Hg. under a load of 30 lbs. Power of Operatlng -determinePlston-A check should whether the operating be made to piston can be moved away from its normal pressiure. bosition under about 60 lb./sq. in. oil "Mid" or Put the Selectoi Valve in either the "Cruising" positions and without applyingvacuum "opening" direction. trv to move the piston in the tf ttris can be ilone easily the servo bushing is leaking badly and should-be-replaced.. Also to check-the selector valve for leaks put it in the "Emergency" position and attempt !o move "closing" direction. the operatiirg plston in the

OF UNIT ON TEST RIG

With 60 lb./sq. in. oil pressure the piston should be able to hold a load of 40 lbs. Leakage of Oll Through Untt-There are two good indicatlons of excessiveleakage through the Unit. First, the pressure drop as shown by the oil pressure gage and secondly, the amount of oil flowing from the drain of the Unit. If, with the same setting of the by- valve, "Mid" or there is less pressure when in the "Cruising" position then when in the "Emergency" position there is excessiveleakage by the servo valve or bushing. To check for this leakage substitute a rod of the same diameter as the servo valve and note the oil flow from the drain. If it appears less, then the servo valve is loose but if it is about the same the bushing is leaking and should be replaced. If on the other hand, "Emergency" position the pressureis lower in the the selector valve is leaking or the hole in which the selector valve slides had become damaged. This can be checked by substituting a blank rod of the same diameter as the selector valve and noting the oil flow from the drain. A slight leak at this valve is not serious. The maximum drop in pressure between the emergency and regulating positions should be 5 lbs. Euntlng-If a Unit hunts badly or if difficult to adjust due to its not regulating to the same pressures each time, check the following parts for sticking: Servo Valve Servo Valve Operating Lever Bellows Operating Piston

1801

CHAPTER XVIII

MISCELLANEOUS CONVERSIONS information in this Chapter is General-The taken from various Service Bulletins which deal primarily with conversions, and is for the convenienc6 of personnel involved in the overhaul of engings which for some reason were not changed in accordance with Service Bulletins as thev were issued. In most instances the bulletiis are reproduced word for word; in some cases, however, bulletins have been combined or slightly altered to facilitate usage. Numerical

order has been disregarded, the information appearing in the order used for describing-overhaul procedure -that is, working from the front of the engine to the rear. The material of Service Bulletins through No. 318, dealing with changes or information other than that on conversions. is covered under normal overhaul procedure in the main text of this Manual.

BREATEERS (From Servlce Bulletln No. 818) Current Wasp Jr. Engines incorporate a solid plug, Part No. 20159, in the nose section at ihe-'location where a breather was formerly installed. A gasket, Part No. 233, is used under the plug. The nose breather, which was found to be unnecessary, was eliminated because of leakage of oil through it in some airplane installations. The left-hand blower section breather has also been eliminated for the same reason and has been replaced by a plug, Part No. 255, requiring an oil seal, Part No. 33891. The right-hand blower section breather assernbly has been redesigned to incorporate a hose connection for use where it is desired to pipe

the breather exhaust outboard. Part No. 38436 assembly replaces the former Part No. 8927 assembly. It is permissible to make the above changes in earlier Wasp Jr. engines where leakage of oil from the breathers is troublesome. This involves no changes within the engine. Substitution of a plug for the nose breather, alone, has proved a satisfactory correction for this leakage in most instances. Either one of the blower section breathers may be replaced by a plug. Before making these breather changes to remedy oil leakage, it should, of coutse, first be made certain that the leakage is not due to something wrong within the engine.

PROPELLER SEAFT FRONT PLUGS (From Servloe Bulletln No. 270) Wasp H1-G, Eornet E-G and E8-G-The propellei shaft front plugs incorporated in these engines have been redesigned to eliminate the possibility of breakage caused by excessive tightening of the former pipe plug 4nd to facilitate removal. Provisions have been made on the large plug, into which is inserted the small plug, to accommodate a wrench, PWA-1733, to

be used for preventing the large plug from turning when installing or removing the smaller plug, which now has a hexagon head instead of an Allen head. The threads have been changed from pipe threads to straight threads (%"18NF-3), so the large and small plugs are interchangeable only in pairs.

PARTS AFFECTEI) 1

New Parts 36783

1

36784

1 1

36639 5747

Unlts

*Hornet **Wasp Note-When

Part Narne

Parts Replaced

Unlts

Plug-Propeller Shaft Front* Plug-Propeller Shaft Front** PIug Gasket

24307

1

299L9

1

11603

1

installing new type plugs, a Gasket, Part No. 5747 must be used.

1802

MISCELLANEOUS CONVERSIONS CONVERSION FROM TEE TWO.WAY PROPELLER CONTROL VALVE TO THE CONSTANT SPEDD GOVERNOR DRTVE (Frorn Servlce Bulletlns Nos. 206 and 234)

Eornet E-G-Provision was made for a constant **a e"*rnor drive to be mounted on the nose "6"iio"- of Hornet E-G engines, starting with -E;;il" No. 2798 unless a Two-*ay valie was Parf,s Requlred

Unlt 5 2 I 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 4 1 I 1 1 1 1 1

Part No. t72 11359 22977 22972 22969 L1625 284L7 L7187 2L678 23533 23534 23535 202 22974 511 243 24L 19672 L76 21680 2L57r 2298r 22978 26597 14058 23529 23528 26598

specified. Engines prior to the above number may be convelted at overhaul to incorporate the constant speed governor front drive as follows:

Part Narne Washer Cotter Pin Pipe Pipe cap Nut Gear Snap Ring Cover Housing Assembly Gear Assembly Pipe Assembly Screen Bolt Nut Gasket Gasket Gear Washer Gasket Screw Cover Pipe Pipe Plug Gear Assembly Anchor Assembly PIug Shaft Packing Nut Bushing Lever Pin Pipe Pipe Carrier

Reoperatlon-Reoperate the Part No. L0727 FE;a- 6gai to Prri No. 26596 in accordance with Fig. 1801.

\-,

Parts l)lsoarded Unlt Part No.

L3280

12342 13067

1 1

12945 t4373

1 1

t234L 15008 8232 L1567 L2343 44 13043 13069 10731

1 1 1 1 1 1 1 1 1

Ream the governor driven gear_bushingi4 the nose section, using PWA-1040 Reamerand PWA-1039Fixture.

H:'-il,s'.J,t"3'f?l ftT,:s,-& ;f';i,#;};; *:-#tr seTi6ePa":l fnl,'-fiflr#::#il"l Fig' 1801'

Ream the the following pWA-1g41 FWA-$bgpwA-iig pWA-711

cam reduction gear bushing using tools: Fixture Atig"i"g g.t noighiifn"u*"t Finfihing Reamer

iii"";' pipe rss"-Etv Ir i"rtuu"a ifi end of th" the bracket located on the inner snap ring of the front main crankcase. Install the Part No. 19619 Cam Reduction Gear in the_ bearing_ . Assemble the Part No. 19672Propeller Diive Gear on the shaft of the cam reduction gear.

1803

MISCELLANEOUS

CONVERSIONS

REAM .406 !.ooo5 IN HOUSING R22967

./

, . f i o r n .D R I L LT H R U 373i.ooo5DtA.REAM + DEEP$xas' CHAMFER I N F I X E DG E A R

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BOTTOM TAP i DEEP STAKE PLUG A-26598 SECURELYIN PLACE AS SHOWN.

F ig. 1801

Note-The flange side of the propeller drive gear should be adjacent to the bearing when properly installed, this being contrary to the former position of the gear. The front or flat side of the gear should have the word "Front" etched on to insure proper installation at future overhauls. Install the bearing in the usual manner and install the Part No. 28417 Intermediate Gear on the Part No. 28320+10 Bushing. Install Part No. 23535 Pipe Assembly on the anchor plate with elbow and fitting at Part No. 64 Dowel and securing it with Part No. 202 Screw, and Part No. 22974 Bolt. Use Part No. 172 Washer and Part No. 511 Nut with this bolt. Install the bell gear and bearing in accordance with regular practice. Then install the Part No. 26596 Fixed Gear in the Part No. 23533 Reduction Gear Housing in accordance with regular practice. Insert Part No. 26587 Pipe through the reduction gear housing and into the hole in the fixed gear. This hole in the reduction gear housing is located directly in front of the governor drive pad. Cover the pipe with Part No. 14058 Cap using Part No. 243 Gasket under it. Wire the cap to the housing securely. InstaII the Part No. 23534 Governor Driven Gear in the reduction gear housing locking it in place with

Part No. L7L87Locking Ring. Install the reduction gear housing in accordance with regular procedure. Note-The backlash between the new Part No. 28417 Intermediate Gear and the Part No. 23534 Governor Driven Gear Assembly located in the nose section should be .004"-.0t2", replace at .020". When installing these new parts, the backlash circuld be within the limits, but if there should not be enough backlash, the large face of the Part No. 23009 Bushing in the nose section should be faced off enough to give the desired backlash. If the clearance should be excessive, it will be necessary to replace the Part No. 23009 Bushing. After securing the housing in its place, insert Part No. 22977 Pipe in the ageat the right of the governor control pad. Install Part No. 22972 Pipe located in the same age and cover with Part No. 22969 Cap with a Part No. 241 Gasket in between. Install the governor drive unit using Part No. 21680 Gasket under it. Fasten securely with four (4) Part No. 172 Washers and four (4) Part No. 21571 Nuts. Install Part No. 2298L Cover in the sump in place of the two-way valve.

1804

MISCDLLANDOIIS CONVERSIONS

PROPELLER

SEAFT ADAPTATION TO HAMILTON STANDARD CONTROLLABLE, CONSTANT SPEED AND HYDROMATIC PROPDLLERS (From Servlae Bulletln No. 268, Revlslon D)

Wasp El and El-G andEornetE-G and D2-G ;Prgg9Îer sfalls in Wasp. engines starting. with No. 7483 and Hornet engines starting nl! T:: the 3031 were designed to accommodate either

constant speed or hydromatic propeller. As manufactured, these shafts incorporated the foUo*i"g adapting parts:

Part Narre

Unlts

Wasp Hl and El-G

Eornet E-G and D2-G

299L8 24308 Gasket - Propeller Shaft Front Plug 1 PIug - Propeller Shaft Front 1 36784 36783* 29920 27505 Plug - Propeller Shaft (Screw Type) 1 1 2992L None Washer - Propeller Shaft Screw Lock 24304 None Screw - Propeller Shaft Plug Lock Washer 3 11618 None Washer - Propeller Shaft Plug Screw 3 None 27407 1 Screw - Propeller Shaft Plug None Nut - Propeller Shaft Plug I 5213 None LL754 Pin - Propeller Shaft Plug Nut Cotter 1 5747 None Gasket - Propeller Shaft Plug 1 None PIug - Propeller Shaft PIug 1 36639 *Part No. 36783, PIug - Propeller Shaft Front, supersedesPart No. 24307. See instructions entitled "Propeller Shaft Front Plugs" in this chapter. If hydromatic propellers are to be installed on the subject engines, the above listed parts must be removed from the propeller shafts. Conversely, if after using a hydromatic propeller, it is desired to install a two-position or constant speed hub, the above parts must be reinstalled ii the propeller shaft. Propeller shafts in early engines of the above mo-dl6 *ttictt have nof bdn reoperated to accommodate a hydromatic propeller may be sent to United Airports, Rentschler Field, East Hartford, Connecticut, for reoperation.

There is a slight difference between the internal thread size of production shafts designed to accommodate the hydromatic propeller, and reoperated shafts. Therefore, when ordering distributor valves for hydromatic propellers, it should be specified if the shafts are reoperated or not. Propeller shqftg may be identified !V--egsu-1ing the internal threads at the front of the shaft. The internal thread sizes in Wasp and Hornet engines and the correct distributor valve assembly for each are listed in the following table:

Englne Model

Type Shaft

Thread Slze

Wasp H1 and H1-G

Reoperated

214-16

Wasp H1 and Hl-G

Current St'd

2y4-L6N-3

Reoperated Hornet E-G and E2-G Current St'd Hornet E-G and E2-G Current St'd Hornet E3-G *Hamilton Standard Propeller Division Part Numbers.

215/16-24Ns.3 2r%6_24N5_3 2y8-L6N-3

Dlstrlbutor Valve Assembly*

55106 (23D40) 55r2t (22D40) 54644 (23D40\ 5462I Q2D40\ 53604 (23E50) 53604 (23E50) 53594 (23850)

PROPELLDR SEAFT (From Servlee Bulletln No. 240) insure the proper assembly Eornet E-G-To of the oil seal spacer in the hydromatic propeller, the length of the splines at the front end of Part No. 27409 Propeller Shaft have been reduced by rZ". If it is desired to install a hydromatic propeller on this model, the propeller shaft should be reoperated, if not already accomplished.

To determine whether a propeller shaft has been previously reoperated, the distance from the front end of the shaft to the top of the front face of the propeller spline,s should be measured. If the distance is found to be 2r/a,,, the shaft has not been reoperated as the distance should be 2Yz!'.

1805

MISCDLLANDOIIS CONVERSIONS Note-This reoperation applies only to those propeller shafts that have piping installed for the hydromatic propeller. If it is desired to convert engines now in service to incorporate piping for the hydromatic propelIer, it is necessary to return the propeller shaft to the factory for reoperation and in this case, the above reoperation will also be incorporated. To reoperate the propeller shaft, place it in a lathe and- cut back the end of the splines which are located at the front of the propeller shaft, tl". The rl" radius should be maintained. Pbtistr the reoperated portion of the propeller shaft with crocus cloth. If the propeller shaft has a Part No. 240 Screw instead of tlie wide spline at this point, the screw

should be removed before reoperating the shaft. It will also be neccssary to duplicate the No. 10-32 NF-3 hole which is one inch directly toward the rear of the shaft. The diameter of the small counterbore of the No. 10-32 NF-3 hole is Vn" , and the depth rs rZ," from the O.D. of the splines. The diameter of the Iarge counterbore is rYn", and the depth is /n". The propeller shaft should be cleaned thoroughly after reoperation and if Part No. 240 Screw is used, it should be installed in the new location. The propeller shaft should be assembled to the engine in accordance with the usual procedure.

CYLINDER ASSEMBLIES (Frorr Servloe Bulletln No. 81f) Eornet E, E-G, E2-G and E8-G EnglnesHornet E3-G Engines incorporate cylinders with heads which have been strengthened at the dome and at the attaching threads. The design of the head at the valve guide bosseshas also been changed and the valve spring lower washers no longel seat against the valve guides as formerly, eliminating a so'rce of possible damage to the gluoes'

E,E-GandE2-Gengines. TheseCylinders,Part No. 36889, require the same valve spring lower washers and valve guides as the Part No. 3427L Cylinders, and this should be borne in mind when ordering spare Part No. 36889 Cylinders or spare valve guides and valve spring lower washers for these cylinders.

The E3-G cylinders, Part No. 34271, can be used as replacementson E, E-G and E2-G engines, but requiie long reach spark plugs, which makes it advftable to-install the Part No. 34271 Cylinders only in complete sets.

To take advantage of the additional cylinder head dome strength-made possible by useof the long reach,spark plug, it is of course desirable to use-_Part No. 34271 for replacements on. the earlier Hornet E Series engines, where it -o possible and feasible to change over completely to long reach spark plugs.

Spare cylinder assemblies,which are similar to the Pait No. 3427I Assemblies,but in which short reach plugs are used, are not available for

The following table is to assist in ordering spare cylinders, valve guides and valve spring lower washers:

Unlts Per Englne

New Type Part No.

Part Narne

I I I I 9 I

3427Ix* 36889* 34269 34270 8?59 8759

Cylinder Mach. and StudsAssy. Cylinder Mach. and Studs Assy. Guide - Valve Inlet Guide - Valve Exhaust Valve Spring Washer Valve Spring Washer

Old Type Part No.

27845 L420 23408 9358 9356

Unlts Per Dnglne

I I I I I

*Accommodates short reach spark plugs. **Accommodates long reach spark plugs. (Removable Type) CRANKSEAFT FLYWEIGETS (From Servlae Bulletlns Nos. 218' 275 and 810) it becomes necessary to reWasp Junlor-If place-the flyweights, it is important to determine i'hether the crankshaft is balanced for the ltght or heavy type flyweights. Starting with Enghe No. L248, all Wasp

Juniors were equipped with the heavy type flyweights and will require no alteration of the crankshaft balance weight if new replacement heavy type flyweights are used. It is also possible that engines, which originally incor-

1806

MISCDLLANDOUSCONVDRSIONS porated the light type flyweights, have previously been converted to accommodate the heavy type. The heavy type flyweights bear the Part Nbs. 34465, 34462, 34464 or 34463, stamped on the flyweight face. Light type flyweights were furnished in Engine Nos. 717-726 and 73L-L248. It is also possible that engines prior to these have been converted in service to incorporate crankshafts with the light type flyweights. These flyweights may be identified by the Part Nos. 2390L,23900, 2707L or 27072. Replacement flyweights which are supplied as sparesare all of the heavy type and if installed as engines balanced for the light type flyweights, the crankshaft will have to be rebalanced bv removing the Part No. 167 Rivet from the outer center position of the rear counterweight. Flyweights supplied for spares will be of the new heavy type. If it is desired to replace one flyweight, both will have to be replaced to maintain the proper crankshaft balance. To remove the Part No. 167 Rivet, drill a sf" hole one inch deep in the peened end of the rivet to be removed. Chamfer at a 60o angle to sufficiently relieve the end of the rivet. Using a hydraulic press and a /8" drift, press out the rivet. By leaving the rivet hole empty, the New Parts Requlred Part No. Unlts

1 1 I 1 2

34465 34462 34464 34463 447L8

crankshaft will remain properly balanced, tf non-nltralloy knuckle plns are used. For instructions regarding balancing of crankshafts when the new, heavier nitralloy knuckle pins are used, refer to the paragraph on the use of "Nitralloy Knuckle Pins" in this chapter. Installation of new type flyweights necessitates reoperating the flyweight liners to accommodate the larger radius at the rear ofthe new flyweights. The chamfer at the rear of the new flyweights has been increased from 5/4,,x 4bo to rf,, x 48". This reoperation can best be accomplished by placing the rear half of the crankshafl in a 20i' lathe, on a suitable fixture, in such a manner as to center the flyweight liner; then grind the chamfer to the proper depth with a "Dumore" or similar type grinder. If a 20" lathe is not available, this reoperation may be done with a small grinding wheel installed in an electric Regardless of which method is hand drill. used. the liners should be marked to show the proper depth of the chamfer before grinding. Care should be taken not to grlnd beyond After grinding, the the marked depth. chamfer should be stoned or smoothed up with crocus cloth. Install the 4/2x flyweight on the left side and the 9x flyweight on the right side (looking frorn ihe rear forward, toward the propeller). Parts affected are as follows:

Part Name Flyweight'- Inner (AYzx) Flyweight - Outer @%x) Flyweight - Inner (9x) Flyweight - Outer (9x) Expander

Part No. 23902 Screw - FlvNote-The weight, may be reused in the new flyweight, if in suitable condition. Wasp Hl and Hl-G-Wasp Hl and Hl-G engines were at first equipped with two 4fux rlveted type flyweights. It has been found that a combination of one 4rlx and one 9x flyweight is desirable for the best interests of the crankshaft and propeller from a vibration and blade stress standpoint. Therefore, it is recommended that a 9x flyweight be substituted for one of the 4ftx flyweights in the rear counterweight of the current Wasp HL (direct drive) engrnes. Since one of the 4ftx flyweights must be replaced by a 9x flyweight, which is available only in the demountable type, in direct drive engines, it is necessarythat a new 4/2x demountable type flyweight which is heavier and more durable than the original 4/2x flyweight, be substituted for the remaining 4/2x nveted type flyweight to maintain uniformity. Wasp Hl-G (geared) engines still use two 4/2x

Parts Replaced Part No. Unlts

2390r 23900 2707L 27072 TT52T

1 1 1 1 2

flyweights, but when replacements are made it is recommendedthat the demountable type be used. Installation of the new demountable type flyweights (whether two 4rlx are used in geared engines or one 4lx and one 9x are used in direct drive engines), necessitates reoperating the flyweight liners to accommodate the larger radius at the rear of the new flyweights. The chamfer at the rear of the new flyweights has been increased frorn fta" x 45o to l(4" x 45". Part No. 16699 Liner may be reoperated to Part No. 34949 Liner. This reoperation can best be done by placing the rear half of the crankshaft in a 20" lathe on a suitable fixture in such a manner as to center the flyweight liner, and grinding the chamfer to the proper depth with a "Dumore" or similar type grinder. If a 20" lathe is not available, this reoperation may be accomplished with a small grinding wheel installed in an electric hand drill. Regardless of which method is used, the liner should be marked to show the proper depth of the chamfer before grinding. Care should be taken not to grlnd beyond the rnarked depth.

1807

MISCELLANNOUS CONVERSIONS

e{ PART NO.35044 PART NO.34520

Fig. 1802

Fig. 1803

To remove the old.flyweights, dylll a- Lrl" hole-one-inch deep i1^the peened end of the flyweigh! chamfer ?t- 45" to sufficiently reljeve the end of the flyweight and using a hydraulic press and a I" dift, press out the flyweight.

the securing expander which spreads the slotted end of the-scr6w is drawn uf tight. The end clearance of the assembled flyweight is .008".0I2". If necessarv, grind th6 sm6ll end face of the outer flyweight- to-obtain this clearance.

To assemble,use AssemblyTool No. TAM1773 and TAM-L774, making certain that the through screw is tightened snugly and that

The following is a list of parts affected by the installation of t-henew type 9x flyweights an-dthe 4rlx flyweights in direct drive engines.

New Parts Requlred Unlts Part No.

Part Narre

Parts Replaoed Part No. Unlts

I q4q47 Flyweight - Inner 1 $%x) L670I q4948 1 Flyweight- Outer. (4%x) 16200 t q4Q+!(Qx) 1 Flyweight- Inner 1G201 1 @Yzx) L 34945(9x) Flyweight-- Outer 16?00 1 $%x) 2 34949 Liner - Flyweight 16699* 2 2 34946 Screw- Flyweight 2 44718 Expander *May be reoperatedto the Part No. 34949as describedpreviously. . The following is a list of parts affectedby the installation of two demountabletype 4rlx flyweights in leared engines. New Parts Requlred Unlts Part No. 2 3494t

2 34948 2 34949 2 34946 2 447L8 *May be reoperatedto Part

Parts Replaced Part Narrre Part No. Unlts Flyweight - Inner 16701 2 GYd Flyweight - Outer 16700 2 Q%x) Liner - Flyweight 16699* 2 Screw - Flyweight Expander No. 34949 as described previously.

MISCELLANEOUS CONVERSIONS Installation of the new demountable type flyweights necessitatesrebalancing the crankshaft. It is recommended that this be accomplished with a milling machine by milling a flat on the bottom of the rear counterweight to obtain the proper balance. If a milling machine is not availiUt6, it is permissible to use a portable grinder. In either case, it is important that the flat area be at right angles to the vertical centerline of the counterweight. The counterweight should be milled, or ground, to a depth of Vn" measured

(see Fig.1802). centerline atthevertical

S;*,'3;"??1"*rlHt#tiltj'*:t"il:f

EornetE,E-GandE2-G-Replacementofrivet tvp" nv*"ights with the demouitable type necessitates reoperating the flyweight liners to accomNew Parts Requlred Part No. Unlts

2 2 2 2 2

modate the larger radius at the rear of the new flyweights. The chamfer at the rear of the newer liners has been increased from 22Yu" x 45o to 25A"x45". TheFlyweightliner,PartNo.20SlL, may be reoperated as follows: Place the rear half of the crankshaft in a 24" lathe on a suitable fixture in such a manner as to center the flyweight liner. Grind the chamfer to the proper "Dumore" or similar type grinder, depth with a permissible to use a small grinding wheel or it is installed in an electric hand drill. Mark liner to

Parts Replaced Part No. Unlts

Part Name Liner - Flyweight Flyweight - Inner Flyweight - Outer Screw - Flyweight Expander

34777 34520 35044 34521 447L8

itlllf:

After grinding trhe chamfer should be stoned or dressed with a fine emery cloth. The following is a list of parts affected:

205LL* 18597 18598

2 2 2

*May be reoperated to Part No. 34777. It has been found that an accumulation of adverse tolerances may cause interference between removable type crankshaft flyweights and the inside of the crankcase on the subject engine models. In order to insure ample clearance (.060" minimum) at this point, a bevel is incorporated on the outer edge of each flyweight flange. Parts on hand may be used providing there is

New Parts Requlred Part No. Unlts 40661 2 40660 2 40662 2

a minimum clearance of .060" between the flv-is weights and the crankcase. If the clearance found to be less than .060", the flyweights may be reoperated, according to Fig. 1803, but when this is done a steel ring, Part No. 40662, must be pressed into the reoperated flyweight Part No. 35044 to compensate for the weight removed. The following is a Iist of parts affected.

Parts Replaced Part No. Unlts 2 35044 34520 2

Part Name Flyweight - Outer Flyweight - Inner Steel Ring

New parts are fully interchangeable with each other, but are interchangeable with old parts only in pairs. NITRALLOY KNUCKLE PINS (From Servlce Bulletln No. 268) Wasp Jr., Wasp and Eornet-Nitralloy knuclkle pins are now used in latest model"qof the above engines to reduce galling and to prevent possible pickup when assembling and llisassembling pins in the master rods. Future Englne

Model

R-985-B R-1340-H1 and Hl-G R-1690-E, E-G, E2-GandE3-G

spare kluckle pins will !e of_the nitralloy type and,withtheexceptionoftheW"qpJr.Bengines, are directly interchangeable with the previous type pins. See table below for parts affected.

Unlts

Current Nltralloy Knuckle Pln Assys.

Assernblles Replaced

Unlts

8

32L53

4483

8

8

32L54

15318

8

8

32t55

11539

8

1809

MISCELLANEOUS CONVERSIONS Nitralloy knuckle pins for Wasp Jr. B engines arcL.02 pounds heavier per set than the previous tvpe anil the use of them will necessitate rebaiancing the crankshaft to compensate for the additional weight' Spare crankshafts balanced for light type nonnitrilloy knuckle pins can be furnished, providine Part No. 23905 is specified for engines ring pistons, or Part No. 28102 for with hve 'with fbur ring pistons. Otherwise, encines spires which are balanced for the nitralloy knuckle pins will be furnished' When rebalancing Wasp Jr. B crankshafts, for the nitralloy pins there are two conditions to be considered. If the crankshaft has been heavier type flychanged to incorporate the "Flyweights (Removweie[t, as explained under abld T.vpe - Wasp Jr.)" in this chapter, additional fu-eigfrtmust be added to the crankshaft Type ol Knuakle Plns

Type of Flywelghts

Lieht (Non-Nitralloy) Liiht (Non-Nitralloy) Heavy (Nitralloy) Heavy (Nitralloy)

Light Heavy Heavy Light

by employing one unit of Part No. 34460 Rivet (heavy head) in the outer center position of the front counterweight in place of Part No. 25784 Rivet. and one unit of Part No. 167 Rivet in the outer center position of the rear counterweight. In the event that a crankshaft incorpodescribed under rates the Iighter type flyweights, "Flyweights (Removable 'Iype - Wasp Jr.)" in this chapter, additional weight must be added to the crankshaft by employing one unit of Part No. 34460 Rivet (heavy head) in the outer center position of the front counterweight in nlace of the Part No. 25784 Rivet and also one irnit of Part No. 34497 Rivet (heavy head) in place of the Part No. 167 Rivet, at the same iocation in the rear counterweight. The table below outlines the various combinations of flyweights and knuckle pins, and lists the rivets to be used for balancing the crankshaft with these combinations. Rlvets (Outer Center Posltlon) RearCounterwelght FrontCounterwelght 25784 (Light Head) 25784 (Light Head) 34460 (Heavy Head) 34460 (Heavy Head)

The above rivets should be replaced in accordance with the following instructions: Drill a sf" hole one inch dqep iq the-peened end of the iivet to be removed. Chamfer at a

167 (Light Head) None 167 (Light Head) 34497 (Heavy Head)

60o angle to sufficiently relieve the end of the rivet, and, using a hydraulic press and a 54" drift, press out the rivet. Press in the new rivet, and peen over the end with a suitable tool.

PISTON PINS (From Servlce Bulletln No. 288) in material and Wasp Jr. B-Refinements nroc&ses of manufacture have produced a Stronger piston pin which is used in Iater Wasp Jr. BlB2-and 83 engines, beginning with Engine

No. 1248. Because piston pins are one of the most highly stressed parts in the engine, it is recommended that the improved pins be installed at the next overhaul. Parts Replaced

New Parts Requlred Unlts

9 9 9

Welght Per Unlt (Wfth Plugs)

.78lbs. .91lbs. 1.14lbs.

Part Name

Part No.

31795 31806 31796

Pin Assembly- Piston Pin Assembly- Piston Pin Assembly- Piston

In the following paragraphs, which will be of assistance in ascertaining the comect piston pins to be used for replacement in Wasp Jr. Engines, it will be noted that several master balance weights appear. This is due to various weight changes in pistons and master rods. In the case of engines originally equipped with four-ring pistons, but in which bqla-nclng screws have been incorporated in the crankshaft counterweishts to compensate for the additional weight of frve-ring pistons, the original master balance weight should still be used for reference.

Part No.

Unlts

9003 or 3601 13113 17355

I I 9

Part No. 81705- Pln Assembly - PlstonThese pins replace those used on all Wasp Jr. A Engines having crankshafts balanced for fourring, 5:1 compression ratio pistons. The master balance weights which may appear on the crankshaft of the engines in this category are as follows: 37.38 lbs., 37.56 lbs., 38.22 lbs., 38.32 lbs., 38.86 lbs., or 39.04 lbs. These pins also replace those used in {a,sp Jr. B En!"ines havinf crankshafts balanced fol either forir or five r-ing, 6:1 compression ratio pistons. The master balance weights which

1810

MISCELLANEOUS CONVERSIONS may appear on the crankshaft of engines of this category are as follows: 38.22 lbs., 38.44 lbs., 38.95 lbs., 38.99 lbs., 39.10lbs.. 39.97lbs., or 40.35lbs. Part No. 81806-Ptn Assernbly-PlstonThese pins replace those used in Wasp Jr. B Engines having crankshafts balanced for fourring, 6:1 compression ratio pistons, but which actually incorporate four-ring, 5:1 compression ratio pistons. These engines were built with crankshafts balanced for four-ring, 6:1 compression ratio pistons, and require additional weight at the piston pin when using four-ring, 5:1 compression pistons. The master balance weights which may appear on the crankshaft of engines in this category are as follows: 38.22lbs., 38.44lbs., or 39.10lbs. Part No. 31796- Pln Assernbly-PlstonThese pins replace those used in Wasp Jr. B Engines having crankshafts balanced for fivering, 6:1 compression ratio pistons but which actually incorporate four-ring, 5:1 compression ratio pistons. The crankshaft master balance Plston Pln Assembly

31795 31796 31806

weights which may appear on the crankshaft of engines in this category are as follows: 38.95lbs., 38.99 lbs., 39.97lbs., or 40.35lbs. Due to the fact that there have been various changes in master balance weights in Wasp Jr. engines, it is recommended that if there is any doubt as to the correct replacement piston pins, the necessary weights for the correct piston pins be sent to the Service Department. These weights include the connecting rod cluster (master rod and bearing, link rods, knuckle pins, screws and locks), the master weight balance weight (stamped on crankshaft counterweight), and the weight of one piston (stamped on the piston pin boss). The part numbers designated represent piston pin assemblies,i.e., the pin with plugs. The new pin itself, Part No. 3L740, is identical in all three of these assemblies. This part number is marked on the end of the pin. When piston pin plugs are installed at overhaul, it is important that the proper ones be used to maintain proper balance as follows: Plug

9002 (Aluminum) 7735t (Bronze) LL447(Bronze)

New piston pin assemblieshave the assembly number marked on the edge of one of the plugs. In the event that replacement is made of the plug bearing the assembly number, it is important

Unlts Per Assembly 2 2 2

that the new plug be rnarked with the piston pin assembly number for ftrture identification. New type piston pins were first incorporated in Mfrs. Engine No. 1248.

IIEAVIER SECTION PISTON PINS (From Servlce Bulletln No. 200) with Engine Nos. Wasp Hl and El-G-Starting 6244 and 6223 respectively, a heavier section Piston Pin, Part No. 22320 is incorporated in these engines in place of Part No. 1515 Piston Pin. If used in previous engines, the crankshaft requires rebalancing to offset the increased weight of the piston pins. Making this change necessitatesreplacement of all piston pins in the engine. To determine the proper rivet part numbers and also the location of the rivets to be changed, compare the crankshaft assembly with Figs. 1804 and 1805. If the crankshaft assembly number is found to be on both Sketches II and III of Figure 1805, the thickness of the rear counterweights should be measured to determine the proper figure. The rear counterweights shown on Sketch II, Figure 1805, should measure approximately l5%4tt thick, and those on Sketch III, Figure 1806, should be approximately L5%4ttthick.

Reoperatlon-If necessaryto remove Part No. 6040 Rivet, drill a sf" hote one inch deep in the peened end of the rivet; then chamfer at a 60o angle to sufficiently relieve the end of the rivet and press out rivet, using a /s" drift and hydraulic press. Install Part No. 27856 Rivet in place of the one removed, using a 30-ton hydraulic press to peen over the end of the rivet. A suitable adapter should be improvised for the rivet head when using the hydraulic press. When removing any other rivets shown on the sketches, use a 78" drill instead of a fu" drill and also use a l(" drift in place of a 51" dnft. Remove and install rivets as described above. After changing rivets the old master weight should be obliterated and the new weight, which is found below the sketch, stamped on the crankshaft.

1 8 11

MISCELLANEOUS CONVERSIONS

FOR LATER PART NO. 18385 CRANKSHAFT ASS'Y. AND ALL PART NO. 2O3O5 CRANKSHAFT ASS,IES, REMOVE PART NO.25743. INSTALL PART NO. 27655.

FOR EARLY PART NO. 18385 CRANKSHAFT ASSEMBLIES, REMOVE PART NO. I3898. INSTALL PART NO. 27457. FRONT COUNTERWEIGHT

ON ALL PART NO, 18385 AND PART NO. 2O3O5 CRANKSHAFT A S S E M B L I E S , ' R E M O V EP A R T NO. 6040. INSTALL PART NO.27A56,

REAF COUNTERWEIGHT

CRANKSHAFTASS,Y NO. r8385 20305

OLD MASTER WEIGHT 55.05 LBS. 55.05 LBS. SKETCH I

Fig. 1804

NEW MASTER WEIGHT 55.68 LBS. 5s.68 LBS.

r8t2

MISCELLANEOUS COIVVERSIONS

NO. t3898 NO.27657

SKETCHII FRONTAND REAR COUNTERWETGHTS. (Z EACH) CRANKSHAFT ASS,Y.NO.

t23to

OLD MASTER WEIGHT 52.98 53.6r 55.06 55.06 55.06 5s.06

t5396 t5400 t5431 t5746 t5798

LBS. LBS. LBS. LBS. LBS. LBS.

NEW MASTELWEIGHT 53.61 s4.24 55.68 55.68 55.68 55.6E

LBS. LBS. LBS. LBS. LBS. LBS.

NO.r2295 NO.27854

SKETCH III FRONT AND REAR COUNTERWETGHTS. (Z eeCn)

CRANKSHAFT ASSY NO. l23to 15396 t5400 t5746

OLD MASTER WEIGHT 52.98 53.6 | 55.05 55.05

LBS. LBS. LBS. LBS.

Fig. 1805

NEW MASTER WEIGHT 53.6t LBS. 54.24 LBS. 55.O8 LBS. 55.68 LBS.

1813

MISCELLANEOUS COIIVERSIONS ROCKER AND ROCKER BEARINGS (From Servlce Bulletlns Nos. 235 anil262) Wasp Jr. B Englnes-Curr_ent W".p Jr. B Engines incorporate imp-roved rocker arm-assemblies. The rocker is larger to accommodate a greater capacity double row bearing as,well as a stronger valve adjusting screw with finer

New Parts Requlred Part No. Unlts 10678 I I

L0677

18 18

9016 95L4

18

9294

Part Name Intake Rocker and Ball Cup Assembly Exhaust Rocker and Ball Cup Assembly Rocker Bearing Valve Clearance Adjusting Screw Assembly Valve Clearance Adjusting Screw Lock Nut

Chapters II and V of this manual should be referred to for instructions on disassembly and assembly of the rocker arms. Wheninstallingthelargetyperockers,acheck st ouid be made" to aefbi#iire that ;"tr;l;;; L"i*"e" the rocter and ilit"ti;i;;;;";;iirtr i"a"r-"""t "r U"". If the clearance is insufficieirt, it should be obtained by burring off the ridge INSTRUCTIONS

8955 Ll52l 14779 14814 20L42 20388 26843 26841 2ol4l 37564 20255 26090 33393 27507 27503 13705 7L748 287LL 33395

Parts Replaced Part No. Unlts 9 3734 3735

I

314-D 3725

36 18

551

18

on the bottom of the rocker boxes and also burring the sides of the rocker boxes with a power driven, flexible drive rotary file. , r , r r r--- :--_ ar_ __--____,^ To determine the amount of metal to be re' moved, a heavy tvpe rocker assemblv.should be used as a guide as some cylinders will require less burring than others.

FOR INSTALLING PRATT AND WEITNEY ON WASP JR. B ENGINES (Frorn Servlce Bulletln No. 320, Revlslon A)

The following instructions cover the changes required to con"vert Wasp Jr. B Engines having either the grease type or one-shot rocker box lubrication system to permit the use of tt e Pratt Part No.

threads. These parts are interchangeable only as complete assemblies. The following is a list of the parts affected if it is desired to make this ;;"-;; uua'E's'

LUBRICATOR

& Whitney automatic lJ'bricator. The parts listed.below .are required for converting a grease-lubricated engrne to one wrth automatic lubrication.

Part Narre

Gasket - Rocker Shaft Plug - Cylinder Head Gasket - Rocker Cover Spring - Rocker Cover Shaft - Rocker Ball End Pipe Assembly - Inter Ear Pipe Assembly - Connection to Main Feed Hose Clamp Fitting - Inter Cylinder Clamp Brace Clip Bushing Screw Nut Pipe Assembly - R,ear Case to Lubricator Pipe Assembly - Lubricator to Cylinder (Lower)

Quanttty 18 18 18 18 18 L2 T7 1 20 40 18 2 L 1 I 1 1 1 1

t8t4

MISCELLANEOUS CONVERSIONS Part No. 28709 32330 22747 22348 LL42 12009 32966+4 12L84 30489 31724

Part Narne

Pipe - Lubricator to Cylinder (Upper) Lubricator Bushing - Reducing Elbow Gasket - Lubricator Nut Stud Grommet Rocker Shaft Seal Seal - Rocker Shaft

Dlsassernbly-Remove the following parts in accordancewith regular practice: 1 . Rocker box covers, gaskets,and rocker box cover spnngs. 2 . Push rod assemblies from No. 1 intake, No. l exhaust, No. 2 intake, No. 2 exhaust, No. 3 intake, No. 3 exhaust, No. 4 exhaust, No. 7 exhaust, No. 8 intake, No. 8 exhaust, No.9 intake, and No. 9 exhaust. Greasefittings from all cylinders. 4. Rocker shafts from all cylinders. 5 . Remove Part No. 134 Plug from the left side of the rear section just below the gun synchronizer pad. b . Remove the fuel pump and also the fuel pump drive assembly. Remove the present fuel pump attaching studs and also the rear section to blower attaching nut located below the fuel pump pad. 8. Remove primer line clamps from No. 1 Intake Pipe. t).

a, t .

Reoperatlon-The twelve Part No. 10905Push Rod Assemblies should be reoperated to Part No. 20508 Push Rod Assemblies as follows: Remove the Part No. 10667 Ball End from the end of the push rod which seats in the ball end socket in the tappet (crankcase end of rod), and replace with Part No. 20388 Ball End in accordancewith regular practice. the push rod is not Iong enough after assembling new baII ends, a Part No. 10942 Spacer may be inserted between the push rod and ball end to obtain the proper length. The rounded edge of the spacer should be toward the ball end. and in no case should more than one spacer be used under a ball end. Due to possible interference of the rear section attaching stud when assembling the lubricator, it is best to check the projected length of the stud which should be 94" as measured from the blower face. If the length exceedsthis, the end of the stud should be filed down to obtain this length. A Part No. 12009 Nut should then be installed on the stud in place of the nut previously removed. Note-If

Quantity 1 1 1 o

2 2 4 1 18 18

Assernbly-Install two Part No. 20142 Rocker Shafts in each cylinder in place of the former Part No. 8952 Rocker Shaft, and secure with Part No. 12606 Nut. Note: A new Part No. 8955 Gasket should be used beneath each Part No. 12606Nut. Part No. 30489 Oil Seal should be used between these gaskets and the cylinders, and Part No. 31724 Oil Seal should be installed between the washer and the cylinder on the small end of the rocker shaft. Install two Part No. 11521 Plugs in each cylinder where the grease fittings were removed. Install Part No. L4814 Rocker Cover Springs in place of ones removed. Assemble 18 units of inter-cylinder fittings, Part No. 20255, which connect the rocker shafts of adiacent cylinder; also assemble the 17 Part No. 2OS+g Inter-Ear Pipe Assemblies to the rocker shafts of all cylindeis except No. 1 Intake. On No. 1 Intake Rocker Shaft assemble the Part No. 26841 Pipe Assembly - Connection to Main Feed. Tighten pipes securely, making sure that the tee connection of the Part No. 26841 Pipe Assembly faces the rear of the engine. hose connections connect the Note-Where two pipes together, it is first necessary to slip the hose on one of the two mating pipes. After the pipes have been tighiened and properly aligned-, slide ttie hose over the gap between the two pipe assemblies.Part No. 37564Clgryn sfrbUa be used to bind both ends of the hoseconnections securely. Install four Part No. 32966 * 4 Studs in the fuel pump pad in place of those pr-evioully removed. When properly installed, the height of the stud from th-efulel pump pad should be 23f". Install the Part No. g23g0 tubricator and FueI Pump Drive Assembly on the fuel pugp driyg pad in the rear section, using a Part No. 1142 Gasket between the lubricalor and the pad. Install the fuel pump in accordance with- regular practice, usine i Pait No. 1142 Gasket between ihe fuei pum-p and drive. Install a Part No. 22348 Elbow in the oil inlet and another in the oil outlet of the lubricator. Note-The oil outlet is located at the bottom of the lubricator and the oil inlet is in the center of the lubricator housing.

1815

MISCELLANEOUS CONVERSIONS Install Part No. 22747 Reducing Bushing in the rear section hole from which the Part No. 134 Plug was previously removed. Install Part No. 22348 Elbow in this reducer. Connect Part No. 287t1Pipe Assembly from the oil inlet side of the lubricator to the Part No. 22348 Elbow in the rear section. Connect one end of Part No. 33395 Pipe Assembly from the oil outlet side of the lubricator and one end of Part No. 28709 Pipe to the tee connection of Part No. 26841 Pipe Assembly. The Part No. 33395 and Part No. 28709 Pipes should be connected together by means of Part No. 20141Hose. The Part No. 33395 Pipe Assembly should be secured to the rear section with Part No. 27503 Bushing, Part No. 27507 Clip, and Part No. 33393 Brace. Fasten the brace to the most convenient blower to rear section stud, using Part No. 12009 Nut in place of the present rear section attaching nut. Part Nos. 13705Screw and 1L748Nut should be used to fasten the brace and clip together. Part No. 26090 Clamp should be used to fasten the Part No. 28709 Pipe and the primer line of No. 1 Cylinder to the intake pipe. Part No. 8650 Screw and Part No. 8651 Nut from the old clamp should be used to fasten this clamp securely. Part No.

32330 33395 28709 20L4I 33393 27507 13705 27503 11748 12009 32966+4 22348 22717 L142

\-

Install push rods, check valve clearances and install rocker box covers with new gaskets. Note-Before starting the engine, the rocker box lubrication sYstem should be primed with engine oil. Adiustrnent of the Pratt & Whltney Lubri' cat"or-Located on the Iubricator is a scalefor the adiustment of oil flow to the rocker mechanism. When first installing this device on an engine, it is best to set the arrow at a point somewhere between one (1) and one and three quarters (1?r) on the scale. However, this may not be a nerilanent setting, but may be used during the hrst eneine test'after installation of the unit. As a pr6caution it is well to remove the rocker box cbvers after about 10 minutes of running to see if sufficient oil is being furnished to the rocker mechanism of each cylinder. If an over supply is being furnished, it is likely to cause sti'efit smoLine?om the exhaust, which may be colrected by Jetting the pointer at a lower position on th6 scale.* If there is not enough oil found in the rocker boxes, that is, if the springs, washers and rockers are not wet with oil, adjustment should be toward the higher end of the scale. having a one-shot lubrication Engines already -converied to incorporate the svsteir mav be as follows: system lubrication altomatic

New Parts Requlred Part Narne

Lubricator Pipe Assy.- Lubricator to Cylinder (Iower) Pipe - Lubricator to Cylinder (upper) Hose Brace CIip Screw Bushing Nut Nut Stud Elbow luslring- Reducing Gasket Lubricator

.Fli:*::nBlI-_LtTl"l?""" Feed toMain ?331" Pipe Assembly - Rear Case to Lubricator 287LL

Clamp 26090 *Used on engines not hiving the Part No. 26843 Inter Ear Pipe Assemblies. Dlsassembly-Remove the fuel pump and fuel pump drive assembly as previously described. Aho remove the fuel bump-hold down studs and the blower to rear tiold down nut located beneath the fuel pump. Remove the two pipes leading from the oneshot valve to No. f ind No. O Cylinders, also remove the valve from the left side of the rear section.

Quantlty 1 1 I 2 1 1 I 1 1 2 4 3 1 2 L 1 1 2

Assernbly Note-Some engines "pipe may have earlier type assemblies than those inter-ear now furnish-ed' In this case both the tee connection pipe of No. 1 Cylinder and its matins pipe assembly will have to be replace-d-bYa Patt No. 26841 Pipe Ass-embly--Connectio^n to Main Feêdand a Part No. 26843 PiPe Assembly. On No. 6 Cylinder the inter-

1816


$x+ s" cHAM FER

:469!.ooo5 REAM

IF THE DEPTH OF THESE HOLES IS LESS THAN THE REQUIREDAMOUNI, THEY SHOULD BE INCREASEDTO AGREE WITH THE PROPER DIMENSIONS.

Fig. 1806

ear pipe assembly having the tee connection should be removed, and the inter-ear pipe assembly not having the tee connection, which was removed from No. 1 Cylinder, should be used in its place. If the Part No. 26841Pipe Assembly - Connection to Main Feed is now installed on the Unlts Per Englne 6 12 6 L2 12 12 12

Part No.

engine, the one on No. 6 Cylinder should be replaced by a Part No. 26843 Pipe Assembly. , The remaining parts should be assembled in accordance with instructions previously given. The following table provides a ready means of determining the correct push rod arrangement for Wasp Jr. B engines equipped with either an automatic lubricator or the one-shot system: Locatlon

Descrlptlon

10905 Push Rod Assembly Which consists of: Ball End (plain type) 10667 Push Rod 10904

Ir:JLet rt4,5, 6, 7 cyls. Exhaust 15, 6 cyls.

20508 Push Rod Assemblv Which consists of: 10667 Ball End (plain type) 20388 Ball End (drilled type) 10904 Push Rod

I n l e t # 1 ,2 , 3 , 8 , 9 c y l s . Exhaust #1, 2, 3, 4,'1, 8,9 cyls.

All drilled type ball ends should be installed on the crankcase-eirdsof the respective push rods. Wasp Jr. Engines incorporating-the Pratt & Whitn6y type rocker lubriiator, now incorporate of stroke regulator assembly an improved type in theie units. The new type stroke regulator assembly has a slightly largdr baII and t[e method of feening the lip of the regulator has been discarded in

favor of spinning. It is recbmmended that the old Part No. 27606 Stroke Regulator Assembly in eng-inesnow.in service be ieplaced by the improved type which is also Part No. 27606. When making this change, the Part No, 27434 Lubricator Housing should be checked and if necessary, reoperated in accordance with Figure 1806.

18 1 7


INSTRUCTIONS FOR CHANGING THE LOCATION OF THE OIL PRESSURE RELIEF VALVE (Frorn Servlce Bulletlns Nos. 159 and244) Wasp Jr. B-Due to the occasional loss of oil pressure caused by foreign matter in the oil becoming lodged on the relief valve seat on engines equipped with relief valves in the oil pump, it is recommendedthat the location be changed to the rear section at the discretion and convenience of the operator. Remove the No. 9050 and No. 9051 Outer and Inner Plugs respectively, from the left-hand side of the rear section just above the oil pressure screenchamber. Remove the oil pressurerelief valve assembly complete from the oil pump. Install No. 9051 Inner Plug in oil pump. Install Plrg, No. 13119, in pumps with high- boss and Plug, No. 16443,in pumps with low boss. Cautlon-The No. 13119 and No. 16443 Plugs are used to lock the No. 9051 Plug in place.

If the No. 13119and No. L6443Plugs do not screw up enough to tighten against the No. 232 Gasket, their internal lugs should be shortened the necessaryamount. The No. 9048 Bodv removed from the oil pump should be installed in the rear section. Assemble the No. 1138 Plunger and No. 6091 or No. 980 Spring. Assemble No. 8698 Screw in No. 8700 Cover and install cover with No. 234 Gasket. Assemble No. 501 Nut on end of screw. After the engine has been run, and the oil pressure adjusted, the No. 8699 Cap should be installed and safetied.

New Parts Requlred

Unlts 1 1 I

Part No. 13119 8700 16443

Parts Replaced

Part Narne

Inner Plug (Pump with High Boss) Cover Inner Plug (Pump with Low Boss)

Wasp Hl and Hornet E-Due to the occasional heavy breathing experiencedshortly after starting on Wurp Hl and Hornet E Engines having the relief valve installed in the front of the sump, an oil relief valve has been made available for installation on the rear section to obviate this difficulty. This relief valve is installed on the left side of the oil screen pressure chamber and Part No. 32986 26680 26679 26676 26677 26678 2t352 16443 9051 237 6091 234 232 6924 PWA-978 27451

Unlts Part No. Part Name 1 9050 Outer Plug 1

12830

Cover (Pump with High Boss)

1

9049

Cover (Pump with Low Boss)

incorporates a by- line which conveys the relieved oil to the inlet side of the oil pressure pump. Note-Thls change cannot be lncorporated on engines where lt ls deslred to use the flat type hotspot. The following parts should be used if this change is desired by operators:

Part Narne

Quantlty

1 Pipe Assembly Oil Pressure Relief to Pump Connection Oil PressureRelief to Oil Pump I Plug Oil Pressure Relief Body Oil Pressure Relief Plunger Oil Pressure Relief Cup Oil PressureRelief Elbow Plug Plug .l Gasket Spring 1 I Gasket 1 Gasket Gasket 1 Wrench Spacer Relief Valve (Useonly on engineswith NA-Y9A, NA-Y9B, NA-Y9E, NA-Y9E1 and NA-Y9H Carburetors. )

i

1818

MISCELLANEOUS CONVERSIONS The following parts not marked with an asterisk should be used in addition to the above parts when either the NA-Y9C or NA-Y9G

Part Narne

Part No.

33050 32t70 26098 2668L 623+4 274L6 27068 13705 LL748 33052* 21379* 32169*

Pipe Assembly - Relief Valve to Carburetor Pipe Clamp - Oil Pressure Relief Clip Bushing Clamp - Oil Pressure Relief Stud Pipe Clip Screw Nut Pipe Assembly - Relief Valve to Carburetor Pipe Assembly - Carburetor Drain Elbow

Parts now in relief valve in front of sump, which are to be installed in relief valve in rear section: Part No. 8698 501 8699

carburetor is installed on the engine with a hotspot. When no hotspot is used,the parts marked with asterisks should be used:

Part Narne Screw Nut cap

Quantlty 1 1 1

Dlsasserrrbly-Remove the present relief valve assembly from the sump in accordance with regular practice and plug up the two tapped holes, using Part Nos. 9051 and 16433 Plugs. Remove the Part No. 13404- rYt6"Plug in the Ieft side of the oil pressure chamber. Before installing any parts in place, it is first necessary to lap the seat of Part No. 26677 Piunger in the Body, Part No. 26676. This operation should be done with a fine lapping compound and the parts should be washed thoroughly after the plunger is properly lapped ln.

Assembly-Install Part No. 26679 Plug in the hole on the left rear corner of the pressure chamber. This plug should be driven in so that it fits snugly. Next instali one Part No. 237 Gasket on the rear of the Oil Pressure Relief Valve Body, Part No. 26676. Over this gasket place Part No. 27451 Spacer and install this body with the spacer in the tYt6"-- 16 tapped hole in the rear section, using a Part No. 6924 Gasket in between the spacer and the pad on the oil pressure chamber. Note-When installing relief valve on engine it is essential that the fuel pump be assembledon the engine. Install Part No. 26677 Plunger in its place in the body. Next assemblethe collar of Part No. 32986 Pipe Assembly on the oil pressure relief valve body, with a Part No. 237 Gasket in between. Install Part No. 6091 Spring inside lhe plunger and secure in place wit=h Pirt No. 26678 Cap and Part No. 237 Gasket.

Quantlty 1 1 1 1 1 1 I L 1 1 1 1

Nos. 8698 Screw and 501 Nut. Note-Part which were salvaged from the old relief valve, should be installed in Part No. 26678 Cap before assembling this cap to the body. Part No. 8699 Cap should be retained from the former relief valve assembly and used on this new assembly after the oil pressure is properly adjusted. Remove Part No. 13119 Plug located in the bottom of the oil pressure pump and install Part No. 26680 Plug in its place. Insert Part No. 21352 Elbow in Part. No. 26680 PIug. Then connect Part No. 32986 Pipe Assembly to this elbow. The above instructions cover the assembly of the relief valve on engines which incorporate one of the following model carburetors: NA-Y9A, NA-Y98, NA-Y9E, NA-Y9E1, Or NA-Y9H When using either the NA-Y9C or NA-Y9G carburetor with a hotsnot. the collar of Part No. 33050 Pipe Assembly should be installed on the relief valve in place of Part No. 27457Spacer. The other end of tha pips should be connected to the inlet connection of the automatic mixture controL unit. In order to clamp this pipe assembly to the hotspot, it is necessaryto remove the rear left stud on the hotspot and replace with a Part No. 623 + 4 Stud. This stud is longer and affords more room for attaching the clamp. Part No. 26681 Bushing and Part No. 26098 Clip should be installed on the Part No. 33050 Pipe Assembly. Fasten the Part No. 32170 Pipe Clamp to the hotspot, using the Part No. 623 + 4 Stud. Fasten the clip and the clamp together using Part No. 13705 Screw and Part No. 11748Nut. The Part No. 27416 Pipe Assembly should be connected in accordance with regular practice, using Part No. 27068 Clip. This clip should be fastened to the nearest magneto stud bolt.

1819


c C - rr^ on o oa

INSTALL ONLY BETWEEN REAR S E C T I O N A N D V A C U U MP U M P D R I V E HOUSING.

rfii'ri

o

INSTALL ONLY BETWEEN VACUUM PUMP DRIVE HOUSINGAND VACUUM PUMP (OR COVER).

Fig. 18064

When not using a hotspot, the Part No. 33052 Pipe Assembly should be used in place of Part No. 33050 Pipe Assembly and Part No. 2L378 Pipe Assembly should be used in place of Part No. 27416 Pipe Assembly. When using

Part No. 2L378'Pipe Assembly, it is necessary to remove the drain fitting from the automatic mixture control unit and replace with Part No. 32169 Elbow. Clamps are not necessary when not using a hotspot.

INSTRUCTIONS FOR INSTALLING SIDE VACUUM PUMP DRTVE ASSEMBLY (Frorn Servlce Bulletln No. 212) Wasp Jr., Wasp and Hornet-A side vacuum pump drive is available as optional equipment for all the latest single row engines, for driving the Type B2A Vacuum Pump. This drive may be installed without disassembly of the engine. To install this drive it is necessary that Part No. 9634 Vacuum Purnp Drive Assembly be used for Wasp Jr., Wasp and Hornet Engines. The above assembly consists of the following parts: Quantlty 1 2 1 1 1 1 1 1 1 I

Part No. 9629 9630 9626 9627 9628 9631 9633 9705 9632 8

Part Narne Liner Bearing Gear Nut Housing Seal Gasket Spacer Cover Plate Cotter Pin

Drlve - Remove the Method of fnstalllng cover plate and gasket, then install Part No. 9629 Liner in the rear section, driving flange of liner down so that bottom is against shoulder provided in the rear section. To determine if this Iiner has been properly bottomed, measure the distance from the flange of the liner to the face of the pad with a depth gage. This depth should .824". be.802" Cautlon - Be sure liner is pressed down evenly as cocking would prevent obtaining the proper seat. The assembly as received will have two bearings separated by a spacer installed on the gear and held in place by a nut which is fastened with a cotter pin. InstaII this gear and bearing assembly in the rear section, taking care to press it in firmly and to have the bevel gear teeth mesh with the gear already in the engine. The backlash should be .004"-.012".

1820


BEARINGS MUST BE ASS€MBL€D WITH HIGH SHOULDERSOF OUTER RACES TOGETHER AS SHol,vN. THESE CAN BE IDENTIFISO BY MARKING ON OUTER RACE,

TURN OFF CAGE LIP TO FREE OUTER RACE LONGITUDINALLY.

Fig. 1807

Fig. 1808

Install Spacer, Part No. 18431,over the outer race of the bearing. Install Part No. 9633 Gasket over the studs for holding the pump in place. Measure the distance from the top of the Part No. 18431Spacer to the top of Gasket, Part No. 9633, then measure the distance from under flange of the Housing, Part No. 9628, to the bottom of the housing. Grind down Part No. 18431 Spacer to obtain a .002" clearance between the housing and the bearing. Install housing and oil seal over end of shaft. When installing vacuum pump, use Part No. 16532 Gasket between housing and pump. Figure 1806A shows the gasket used between

"the vacuum pump drive the rear section and housing, also the one used between the vacuum pump drive housing and the vacuum pump- (or iovei;. Reversinglhe location of these gaskets may result in improper backlash and blan\ing off-the oil supply to-the pumP, causing srrbsg; quent failure b? Itre p..mp. Siecial care should be taken to insure the proper installation of these gaskets. Note-Misalignment of oil holes in rear section mounting pad and gasket uP to one half the hole diameter is permissible and will supply vacuum pump with ample lubrication.

BLOWER IMPELLER

SIIAFT AND INTERMEDIATE (Frorn Servlce Bulletln No. 214)

Wasp Jr. B - Latest engines having the steel cage type blower bearings incorporate bearings having a formica separator instead of the original Part Nos. 103 and 105 Bearings. Serviceexperience has shown formica separator type bearings New Parts Requlred Unlts Part No. 4 12768 1 1 L

9035 9036 12769

GEAR BEARINGS

to be more durable. Wasp Jr. B Engines have the steel cage type blower bearing cage and may be converted toincorporate bearings as described in the following table:

Part Narne Bearing BalI Bearing - Roller Lock Plate Cage - Impeller Shaft Brg. Bearing

Parts Replaced Unlts Part No,

103 105 5020 5022 5028

2 2 1 1 1

r82l


*tO-Za NC-z THD. a DR|LL AND TAP i 8-HOLES EQUALLY SPACED BOTH ENDS RADIAL LOCATION OF HOLES NOT IMPORTANT.

*1

7

sZ

l

?.g77 DIA.

!'oo5

l

fFig. 1809

Part No. 5022 Cage may be reoperated to Part No. 9036 Cage in accordance wilh instructions given in Figure 1807. A_ssernbly-Install the Part No. 9036 Impeller Shaft Bearing Cage in the blower section in accordance with regular procedure. The Part No. 12768 Bearing should be installed on the impeller shaft with the thrust faces as shown on Figure 1808 Part No. 9035 Lock Plate is used in place of Part No. 5020. If desired, the bearings on the intermediate

gear may also be replaced. The intermediate gear is equipped with a large bearing, Part No. 5028, and a small bearing, Part No. 103. Part No. 5028 should be replaced by Part No. 12769, and Part No. 103 should be replacedby Part No. 12768. No reoperation is required on the intermediate gear cage. Cautlon-Extreme care must be taken to be sure that the thrust faces of the bearings are placed in the proper position as shown on Figure 1808.

EOTSPOTS (Round and FIat Type) (Frorn Servlce Bulletln No. 199) Hotspots on latest engines incorporate a packing and retainer at each end of the casting to obviate any p rssibility of leakage between the casting and hotspot tube. In the event that the hotspot tube becomesloosened in the casting of hotspots now in service, reoperation in accordance with the following instructions is recommended. Reoperatlon-Machine a groove in each end of the hotspot casting from the O.D. of the hotspot tube to an O.D. of 2.877" + .005". This groove should be 7/s2"deep with a %t" radius at the bottom of the groove and chamfered lAt" x 45" at the outer ends (see Fig. 1809). This operation may be accomplished by chucking one end of the hotspot in a lathe and machining a groove with a cutting tool.

Cautlon-Care should be taken not to allow the cutting tool to touch the steel tube. Also drill and tap eight No. 10-24 NC-2 thread holes in each end of the casting using Part No. 23871Retainer as a drill jig for locating holes in casting (seeFig. 1809). New Parts Required Unlts Part No. Part Narne 2 Packing 23873 2 23871 Retainer 16 23872 Screw Assernbly-Place Part No. 23873 Packing in the reoperated grooves at each end of the hotspot. Install Retainers, Part No. 23871, securing in place with the Part No. 23872 Screws.

r822

MISCELLANEOUS CONVERSIONS MAIN OIL SCREEN (Frorn Service Bulletin No. 208)

Installatlon of Sprlng Loaded Check Valve in Wasp Hl and HlrnJt E Englnes-In certain instalhtlions where the oil tanf, is located some distance above the engine and the airplane is allowed to stand a con"siderablelength bf time, oil may seep from the tank through the pressure pump into- the crankcase and . cylinders._ To prevent- this,-a main oil- screen incorporating.a spring- loaded check valve is now installed ir1 the subject engines. This check valve is forced open as soon as an appreciable oil pressure is

ed in the pressuresystem. On stopping th"e engine and ivith the resultant loss of oil press,tr6, the spring loaded valve closes, thus preventing any oil seeping through the pressure brr*p from going beyond this check valve. The oil screen and check valve assembly is directly interchangeable with the plain gil screen formeriy used. T-heplain oil screenwill be continued is a replacement part for those customers who may desire them for engines shipped prior to this change. No. 23215

One-Plece Type Otl Screen and Check Valve Assernbly

Parts Requlred Unlts Part Nc. 1 4-23435 t B-22545 I A-22897 I A-22895 1 A-22896 1 A-501

Part Narne Ring - Oil Seal Oil Screen Assembly (one-piece) Seat Valve Valve Spring Nut

Parts Rernoved Unlts Part No.

8-6075

1

FLOATING GEARS (Frorn Servlce Bulletln No. 287) Hornet E and E-G-BeginningwithEngineNo. 29LL, ali- Hornet enginls incorporate hoating gears and blower intermediat" "orrnt"r.hufT

If it is desired to replace the Part No. 13670 Floating Gear bv thq new, type ea{ }9 !!I1l Gear' the p.rgsenq'blower intermedtate l::'iig-

teeth in place of the stub type. This will insure greater wear characteristics due to greater overLp of the teeth.

lear and shaft assembly. The following^ is a iist of blower intermediate geql and sha& assembliesusedwith Part No. 74134Floating Gear:

gears having theFelrows typer,r'u,p"tiofil gi;J"e"fftf{:ffi#ol{":ttlt3;:"nffi"1il};t#;

Part No. 17232 19477 26L45 18693 26147 Note-The

Part Narne

Blower

Ratlo

t2:l Blower Intermediate Gear and Shaft Assembly 10:1 Blower Intermediate Gear and Shaft Assembly 8:1 Blower Intermediate Gear and Shaft Assembly 11:1 Blower Intermediate Gear and Shaft Assembly 13:1 Blower Intermediate Gear and Shaft Assembly desired. ratio blower proper assembly to be used should be determined by the IMPROVED TYPE REAR SECTION (Frorn Servlce Bulletln No. 220)

Wasp Jr. B, Wasp Hl and Ifornet E-The latest models of th-e above engines have a redesigned rear section which chaiges the location of the oil pressure relief valve from the left side of the strainer chamber to the right side of the crankcase. The reliefl valve rout"es the relieved oil to the inlet or suction side of the oil pump through an internal cored age. Thii rear sectioi also incorporates a nêwtipe oil strainer having a check valve as described under the heading "Main Oil Screen" in this chapter.

On Wasp Jr. B rear sections,.the flow of oil chamber is go-wchanged through th-e oil strainer "outside in" oil flow. from -'inside out" to A new type oil--pump must be used with the rear section-to utifize the new relief valve position. The new rear section may be used in engines-now in service without changing the, oil pulnp by_plugging an_oil pqssage.as described below. When this is done, the relief valve cannot be used in the new position.

t823


H.S.P. PART NO. 5t742 248.24 NIPPLE

r-)

\ J O

r

42970 NUT

)

r^)

(, I

I

(,

5664 CONE

44000

44002

CONNECT.ION REAR CASE

6924 GASKET

Fig. 1810

1824

MISCDLLANEOUSCONVERSIONS New parts are as follows: Part Narne Part No. Plug 4.-9051 Plug A-16443 Plug A-25429 A-232 Gasket Assernbly-The

Unlts 1 1 1 1

Part No. 25429 Plug should be

installed in the new cored ageat the face of the oil pump boss. The Part No. 9051 and 16443 Plugs should be installed in the opening on the right side of the rear section just above the oil pump where the relief valve is ordinarily located on these new rear sections. A Part No. 232 Gasket should be used with Part No. 16443Plug.

CONVERSION TO PERMIT TEE USE OF IIYDROMATIC PROPELLERS (Frorn Servlce Bulletln No. 828. Revlslon A) Wasp Jr. B. and B2-If it is desired to use a hydromatic propeller on a Wasp Jr. B engine, the crankshaft must be reoperated and the engine must be equipped with a nose housing of a reinforced type. Reoperation of the crankshaft is a factory procedure, and the crankshaft should be returned to United Airports, Rentschler Field, East Hartford, Conn. The strengthened Nose Housing and Studs Assembly, Part No. 37968, may be identified by the presence of eight reinforcing ribs on the inside. Wasp Jr. engines built subsequent to No. 1732 (the first engine of the 82 series) require no reoperation to the crankshaft. The first ofthese engines will, however, require a new nose housing having the additional reinforcing ribs on the inside. The strengthened Nose Housing and Studs Assembly retain the original Part Number (39346) and will automatically be furnished on future spare parts orders. On both the Wasp Jr. B and 82 engines the propeller governor continues to be driven from a vertical drive or gun drive at the rear of the en-

gine. Following is a list of oil pipes and connecting parts which are necessaryfor the hydromatic propeller installation. The location of these parls is shown on the accompanying sketch (Fig. 1810). Unlts 1 1 1 I 2 | L

Part No.

Part Name

44000 Pine Assv. - Governor to Rdar Crankcase OiI Drain 44002 Pipe Assy. - Rear Crankcase to?ropelier Governor Oil Pressure 20189 Oil Connection 44738 Bushing - Rear Crankcase Oil Drain 2L352 Elbow 24824 Nipple 6924 Gadket

Instructions for installing a distributor valve assembly and the hydromatic propeller, itself, are furnished by the Hamilton Standard Propeller Division.

PROPELLER SHAFT OIL PLUGS (Frorn Servlee Bulletln No. 8lg and Supplernent l). Wasp Jr., Wasp and Ilornet-Propeller shaft oil plugs now incorporate straight threads to facilitate the removal of the small steel plug when constant speed or controllable pitch propellers are used. A neoprene gasket, which fits into a recess in the aluminum propeller shaft plug, provides an oil seal as well as a method of preventing the steel plug from loosening. Only propeller shaft plugs with this recess for the gasket have straight threads. If it becomes necessary to replace either of these plugs (tapered thread) by one ofthe later (straight thread) type, the mating plug must also be replaced.

pipe (tapered thread) plugs Note-Aluminum (Part Nos. 9737, 10263, 10894, and 10957) are no longer available, the steel pipe (tapered thread) plugs (Part Nos. 11522, LL523, and 11603) being available as spare parts for early type propeller shaft plugs. The design and location of the new (straight thread) plugs when installed in an engine are similar to those shown in the accompanying sketch (Fig. 1811).

1825


Model

WaspH1 Hornet E Wasp Jr. B WaspH1-G Hornet E-G. E2-G

Parts Requlred Units Part No.

Parts Replace Unlts Part No.

Part Narne

|

44077

Plug-Propeller Shaft

10957

1

L

44078

Plug-Propeller Shaft

10263

1

1 1

44073

Plug-PropellerShaft

10894

1

44074

Plug-PropellerShaft

9737

1

AII models

44075

Plug-Propeller Shaft Plug

tL522 or L1523 or 11603

1 L 1

AII models

44076

Seal

At overhaul, the taper-threaded propeller shaft plug may be replaced as follows: Using a counterbore with a pilot, bore out the flared portion of the oil pipe which extends through the aluminum plug. The pilot on the counterbore should be approximately .002" smaller than the I. D. of the pipe and the counterbore itself should be approximately .002" smaller Using a steel drift than the O. D. of the pipe. approximately .002" smaller than the O. D. of the pipe and having a pilot approximately .002" smaller than the I. D. of the pipe, drive out the pipe. The aluminum plug may then be driven from the propeller shaft towards the rear. Note-Some engine models have a stand pipe which must be removed before driving out the aluminum plug. Using a suitable drift, drive the new aluminum plug into place in the shaft. This plug should have a tight press fit. With a drill .004" smaller than the O. D. of a new oil pipe, transfer-drill through the old pipe hole in the shaft to the center of the aluminum plug. Remove the drill and ream the hole .002" smaller than the diameter of the new pipe. The fit of the pipe should be .001" T to .002" T when installed. Turn the shaft over and repeat the drilling and reaming from the other side. Clean out all chips. Using a shouldered drift, install pipe in the shaft, and carefully flare out the ends into the countersink in the shaft with a rounded drift. Carefully inspect the flared ends for tightness and cracks.

DESIGN AND LOCATION OF TYPICAL PROPELLER SHAFT OIL FEED PLUGS

Fig. 1811

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1706

AUTOMATIC MIXTURE AND POWDR CONTROL UNIT

fuel capacity is necessary. This is accomplished by bringing the fourth jet into action by relieving the oil pressure holding its needle controlling this jet on its seat. By the proper selection of the various jet sizes, it is possible to obtain any desired fuel consumption for the three possible operating conditions. In the emergency position, oil pressure is applied only to the age which is directly connected to the opening side of the operating piston. All other pressure agesare blocked off. Similarly, in this position all drainage ages are open except the drain from the needle valve. By applying pressure to one side of the operating piston and opening the other side to drain, positive opening of the pressure control valves is assured. The two jet operating pistons are both open to drain and being spring loaded, the needle valves are thus open giving maximum fuel capacity in the carburetor. In case of loss

of engine oil pressure, a spring is provided which operurthe pressure control valve, i.e., similar to throwing control into the emergency position. In the mid position (see Fig. U02) the two direct connections to the operating piston are closed off and the pressure and drain connections to the needle valve are opened thus putting the regulator into operation. The age to the range-shifter piston is still open to drain so the pressure maintained will be the higher absolute figure corresponding to the lower altitude. Only one ofthe jets has been cut off to compensate for the first altitude condition. In the cruising position (see Fig. 1703) the only change from mid position is to shift the range spring so that regulation to a higher altitude is obtained and at the same time cut out the second needle controlled jet, thus giving the proper carburetor metering for the regulated altitude.

DISASSEMBLY Remove bellows housing cover plate. Remove operating and range-shifter cylinder body. Be careful not to lose selector valve locating pin spring. Take range-shifter spring out of open bellows. Unscrew operating piston guide and remove piston. Pull off range-shifter spring thrust plate. Unscrew range-shifter piston guide and remove adjusting nuts from shaft. Remove range-shifter piston assembly. If cup leather catches in threads turn piston as if removrng nut.

Shake selector valve locating pin out of hole and push selector valve out through drain end. Do not pull through oil seals. Split servo needle valve lever. Be very careful not to break evacuation tube on evacuated bellows. Remove both bellows together. Compress enough to allow pilot on evacuated bellows to clear case. Bellows may be separated if necessary by unscrewing connecting spool. Remove plug at end of servo needle chamber and take out needle. Pull jet piston out of cylinders at bottom of urutr.

CLEANING Wash all parts with engine washing fluid. INSPECTION 1. Gaskets-Be condition.

sure all gaskets are in good

2. Rubber ring oil seal should be replaced if damaged or roughed up. 3. Check servo needle for scoring. Need not be replaced unless badly scored or it lets too much oil leak into case (can be seen on test rig). 4. If

range-shifter cup leather is roughed

upon edge, replace. 5. Check condition of jet operating piston. 6. If there is a large quantity of oil in open sylphon on disassembly, replace range-shifter shaft oil seal. 7. Check selector valve for rolled up edges on locating pin groove. Stone Iightly if necessary.

1713

TOLERANCE CH MODEL 3/05- 8 AL'TOMATIC

1713

SERVICETABLE OF CLEAA,ANCES No. Parts Fit New Fit I Range Shifter in Shaft Guide. .002L .004L 2 Replace Range Shifter Assy. when leather

Seniceobln Limit .008L

cup becomesworn or torn to the extent that the O.D. of the leather fails to provide an effectiveseal... .002L .004L .008L 3 Range Shifter in Body Housing. 4 Control Valve Lever Button in Bellows .0005L .0045L .0045L Conn. Rod. 5 Control Valve Lever Button in Adjusting .0005L .0045L .0045L Rod. . . .0005L .0025L .003L 6 Pressurc(iontrol Valve in ISushing. 7 Replacc Guidc Oil Scal at each overhaul. .0005L .0025L .003L 8 Pin in Prcssure(lontrol Valve. 9 Replace IJell<-rrvs Assy. if dented or cracked. .0025L .0045 .005L l0 Pressure(jontrol Valvc in Bushing. 11 Replace evacuatcd bellows assy. if dented or cracked. t 2 SelectorValvc in Main HousinC..... . . . . . .0005L .0025L .005L l 3 Operaiing Piston in Housing Body.. . . . . . . .0015L .0045L .006L .002L .004L l 4 Operating Piston in Guide. .010L Replacc all worn or damaged gaskets. Replace all leather oil seals if w
REPLACE ALL WORNOR DAMAGEDGASKETS. REPLACE ALL L€ATH€R OIL SEALS IF NARN TO THE EXTENT THE LEATHER IS A CLEA.RANCEFIT ON THAT THE I.D. ff rHE O.D. OF THE SHAFT. NOTE. WHEN REPLACING PARTS AT OVERHAUL THE FOLLOIy. ING PARTS MUST 8E PURCHASEDAS ASSEMELED UNITS:. CONTROL VALVE LEVER ASSEMBLYT EELLOWS ASSELIELY; EVACUATEDEELLOI(S ASSEMELY., RANGE SHIFTER ASSEUELT' EODY AND EELLOWS STOP ASS.EMSLTIOPERAT|NG PTSTON ASSEUELIi UAIN IIOUSING AND SUSHING ASSEMELT

TOLERANCE CHART MODEL 3/05-8 AUTOMATTC MlXTUR€ CONTROL Fis.1706

1317

INSTRUCTIONS FOR STROMBERG NA.YgE ANI) NA.YgET CARBURETORS OVEREAIIL carburetor should be disI)lsassembly-The assembled for cleaning and inspection each time the engine is given an overhaul. After the carburetor has been removed from the engine and the hot spot and air intake or heater taken off, the halves o{ thg carburetor may be separated by the removal of the fi"llister head screws at the parting surface. The economizer needle, pump sleeve and venturii are held in the throttle body as the _bodies are separated. The pump sleeve should be removed- from the opeiating stem immediately so there will be no dinger oT -packits dropping and becoming bent. Rubber ing is used around the venturii so that if it is found necessaq/ to remove them, they will have to be driven out by using a wooden plug as shown in tr'ig. 1310-4. Before removing-the throttle valves, mark them so they may be returned to the barrels from whici th6y were removed. It should not be necessarvto remove the idle discharge jet assemblies uniess some of these parts should be replaced. The main body parts may all be removed. and Cleanlng-The Inspectlon bodies and all parts should be thoroughly cleaned in gasoline and all agesblown out with compressedair. Parts which should be inspected foi wear are the float assembly, float needle and seat, throttle shaft and bushings, economizer needle, seat and operating mechanisms and the pump stem. All variable parts should be checked to see that their sizes are in accordance with the carburetor specification desired. To disassemble the compound pump unit (see Fig. 1311) it should be removed from the operatini stem ind the four small hexason head dcrews wf,ich hold the stem clip in phc:e should be removed. The connecting rod between the upper and lower piston is milled flat above the cross hole, so it can be held with a wrench when removing the center scfews. Considerable force will be required to loosen the center screw as it has been staked in place as a precaution against its coming loose in service. When the center screw has been removed the upper piston may be lifted out ofthe sleeveand the connecting rod and lower piston can be removed through the bottom of the sleeve. Care should be taken that none of the parts are damaged during disassembly or assembly as they are made to fit with very close tolerances and a small nick or dent might canse a binding action. Replaoements-When ordering replacement parts it is necessary to give complete information concerning the parts desired to avoid delay in shipment or the receipt of wrong parts. Whereever possible, the serial number of the carbu-

retor should be given. A careful reference to the assembly drawings (seeFigs. 1312 and 1313) to determine the correct part number and name, and if marked with an asterisk (*) giving the size as stamped on the piece will greatly facilitate service. A specifiiation sheet givin-g the sizes_gf jets, fuel level, economizer selting, etc., will be furnished (no charge) if you wiii write to the Bendix ProductJ Corforation, Stromberg Carburetor Division, South Bend, Indiana, advising the model of your engine. Parts price lists will also be furnished on request. P-2L463 covers a complete set of gaskets for the NA-Y9E and P-60524 for the NA-Y9E1. Reassembly-All headless screw plugs below the fuel level should be assembled with shellac. being careful not to get it on the end of the plug where it will come off and be carried by the fuel into one of the metering orifices. Headless screw plugs above the fuel level and aII other threaded parts screwed into the bodies should have a compound of graphite and castor oil put on the threads. When it is necessary to replace the throttle shaft, the lever which operates the economizer should be assembled in accordance with Fig. 1310-8. The throttle valves, when in the closed position, should fit tightly. When the throttle valves have been fitted, center them in the wide open,position. If the economizer operating lever has been assembled at the correct angle the throttle valves should be centered. However. when this work is done in the field it mav b6 necessary to file the stop at A, Fig. 1310-8, or bend it toward the screwed-in stop. If it is thought necessary to replace a float needle or needle seat it is recommended that bqlh !,e replaced at the same time as it is very difficult to fit a new needle to an old seat or a new seat to an old needle. In ordering these palts, be sure to give the size of the by- -needle holes in the float seat. These by-bass -and holes meter the fuel during inverted flight their size has been determined to meet the requirement of that particular engine and it is, therefore, important that a seat having the proper size by- holes be used for replacement purposes. The float level should be ry'", plus or minus Ye" below the parting surface, and is dependent upon the thickness of the gasket under the float needle seat. The level should be checked under the conditions encountered in service as regards the fuel used and the fuel pressure or head at the carburetor. If a fuel pump is used. a pre$sure at the carburetor of 3 lbs-.per square incir 11U"

1318

CARBURDTORS gaso-lineat .!10 sp. gr,) shouldbe used in checking the fuel level. A gasket %2" tbickshould be useii first and if the level is not correct use thicker gaskets to lower the level and thinner gaskets to raise it. A change of ,(4" gasket ttrickness will change the level approximately %r". The float needle should have at leaet/6a" travel. If it becomes necessary to replace the mixture control shaft or stop it is important that the stop be located in the conect angular position on ihe shaft. In order to do this.-placeâ small piece of wood in the slot of th'e'outer valve plgle in such a-way that it extends through and will fit in the slot of the inner plate. Place the outer valve plate ln the carburitor in the opening position and the wood key will keep it flom turning. Place the shaft and bushing assembly in the carburetor, adjusting the shAft so tlie screw driver ends fit into the valve, and put in the screws to hold the bushings in place. Slip the washer and stop on the shift and turn until the full rich stop is against the large head screw. Assemble lever, indicator plate and nut on the shaft. Draw nut up until washer strikes shoulder on qhaft. drill and fit pin through stop and shaft. (See assembly draryrng (Ffr. 1312) for section and end view of shaft assembly.) The economizet needle is operated bv an eccentric pin which is part of thi economiier lever stem. This stem is operated by the throttle through two levers and a connecting link. It is important that the economizer lever be located at the ploper angle with the eccentric pin on the economizer lever stem. When replacing the economizer lever stem use a new economizer lever also. The lever should be assembled so that its cetlter line forms a 90 degree angle with the cent€r line of the eccentric pin as shown in Fig. 1310-D. When the lever fqs.leen properly set, tighten the clamp screw and drill stem and one sideof lever for ttie locating pin. Screw pin into place. The adjustment of the economizer needle valve in the holder and the eccentric pin on the lever determine the position of the l6ver when the needle is on the seat and. therefore. the throttle opening at which the lever lifts off the seat. This throttle opening is one of the items of the variable specifications or setting in the carburetor and is given on the spec:ffication sheet, being referred to as "economizer setting", the figure give! being the throttle opening in degrees. By adding 20 or 18 (the angle of the

throttle valve) to this figure the angle which the throttle valve makes with the horizontal surface of the carburetor is obtained. Several economizer settings are in use and the proper one should be determined from the carburetor spec-ification sheet. The first adjustment is made by screwing the needle in or out of the holder so that when placed in the main body the distance from the-top of the slot to the parting surface will be in accordance with the dimensioru as shown in Fig. 1310-C for the economizer setting desired. When this has been done, tighten the nut and pin the needle as per the instructions given in Fig. 1310-C. The two halves should then be assembled and final adjustment made by means of the eccentric on the economizer lever. Check the angle between the throttle and the horizontal surface of the carburetor flange when the needle starts to leave the seat. A simple apparatus to check when this movement starts is shown in Fie. 1310-E. It is made by drilling a hole througli- the center of a %6"-18plug,large enough to allow the free movement of a piece of tubing about 4" Iong. Then by _taking 9ut the- economizer metering jet plug and jet it 19 pos,sible to screw in the other plug and push the tubing up so that it rests on the poinl of lhe qe_edlg. If a slight pressure is put on the tube with the fingers while the throttlb is moved,lhe ulseating of the needle will be easily detected. Adjust the eccentric until the conect angle is obtained. When the adjustment has been made, tighten the nuts, being careful not to move the eccentric, and assemble the cotter pins. When reassembling the compound pump unit, considerable care shbuld be t-aken sb tfr'at ttri parts will be concentric to each other and then checked in the body to see that it works freely before restaking the center screw which hold's the piston in place. The small hexagon screws should be safety wired after tightening. When assembling the upper sleeve and piston into the sleeve fastened in the body, considerable care should be taken so the leather will not be curled up around the piston. The leather should be wet with gasoline and one side assembled in the sleeve, then as the piston is forced into the sl@ve, it should be rbtated so the leather will go into the sleeve evenly. With the throttle yalves open the operating stem may then be hooked in place or the purnp unit arid the two halves of the carburetof assêmbledtogether in the usual manner.

1319

br19 30' -T-

wooD NA-YgE &

N A - Y 9 E I V E N T U R I REMOVAL PLUG.

A SPLIT PIN AS SHC D R I L L& R E A MF O R P'I9O66 PIN WHEN P-20t36 LEVER tS tN P O S | T t O NA S S H O W N .

SETTINGWITHP-17684LINK | - il/32"CENTERS I'j t6c-t8c )- tu32" P-16004 t9-2F 2 ? . 26c-3lc

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c

H E X .H E A D

E NA-YgE & NA.Y9EI CARBURETORS FITTII.IG ECONOMIZERLEVERAND STEM.

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1320

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D OU B L ED E CKP U M P A S S E M B L \ . N A -Y g E& N A -Y gEI C A R B U R E T O R S

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BENDIX STROMBERG CARBURETORCOMPANY

Fig. 13rB

1323

INSTRUCTIONS FOR STROMBDRG NA-YgC, NA-Y9G AND NA-Y9GI CARBURETORS OVERHAUL When the engine is overhauled the carburetor should be disassembled for cleaning and inspection. The carburetor halves should be separated bv removing the fillister head screws at the oirtine surfice on the NA-Y9C and NA-Y9G tarbur-etors, and the nuts at the parting surface on the NA-Y9Gl carburetors. All plugs, screws, etc., at the end of the fuel agesshould be removed. The upper pump cylinder and piston assembly should be removed from the carburetor as soon as the halves are separated. All parts in the bodies, with the possible exception of the idle discharge jet assemblies, should be removed to enable a thorough cleaning and inspection. bodies of the Cleanlng and Inspectlon-The carburetor should be thoroughly washed in gasoline "Td. uU the channels blown out with compressec arr. The throttle valves should fit the bore tightly and if necessary to remove them they should be marked in such a way that they may be replaced in the same way they came out. All variable parts such as metering jets and air bleeds should be checked against the specification sheet of the carburetor being worked on. Examine all movThe float ins parts for wear or irregularities. nidie seat and needle valve should be checked for Ieakage by holding the needle with the point up and tlie seat in place and fiJling the small space above the needle point with gasoline. If any leakase is evident the needle should be lapped in with irocus powder or fine lapping compound. If that doesn-t stop the leakage both the needle and the seat shoulal be replaceil, as it is very difficult to fit a new needle to an old seat or a new seat to an old needle. If necessary to disassemble the accelerating Dump piston assembly, it should be done in the lo[oi'iire manner: The slotted plate held to the uDDer pfuton by four screws should be removed, tli6n uhstake and remove the central countersunk screw. This will allow complete disassemblv of the upper sleeve and piston stem assembly. Afoembly ollhis unit is accomplished by reversine the ibove procedure. Before restaking the ceiter screw, the assembly should be placed in the main body to see that all the parts line up correctly and-there is no binding in any of the parts. If it becomes necessary to replace the mixture control shaft, it is important that the lever be Iocated in the proper angular position on the shaft. In order to do this, place a small piece of wood in the slot of the outel valve plate in such a o'uy that it extends through and will fit in the

slot of the inner plate. The upper plate should be in such a position that all the slots are open. Then install the spring, mixture control shaft, and cover plate. l'he lever should be located on the shaft so that when connected by the linkage to the primer valve lever, this latter lever will be at the full rich stop. The mixture control lever should be drilled and pinned to the stop in this position. Cautlon -Remove the wood stop before final assembly. When it is necessary to replace the primer shaft, care must be exercised to see that the valve is in the idle cut-off and priming position with the lever against the full lean stop. The shaft should be completely assembled except for the pin through the stop lever, and placed in the body so the idle cut-off hole through the conical valve is lined up with the hole from above the throttle. With the valve in this position insert a metal pin through the hole in the throttle bore into the hole in the inner valve as shown in Fig. 1317-D. This will keep the valve and shaft from turning while the stop lever is moved to the full lean or idle cut'off position against the stop. With the stop lever in that position the hexagon nut should be tightened and the entire assembly removed from the carburetor and the stop Iever pinned to the shaft. If the float level is not correct (1" below the parting surface at 3 lbs. fuel pressure at .710 specific gravity) it may be changed by changing gaskets under the float needle valve seat. Thinner gaskets should be used under the seat to raise the float level and thicker gaskets to lower the Ievel. A gasket change of Y64"will change the level approximately /6a". The pump valve should be disassembled and the diaphragms checked, as the NA-Y9G Carburetors between the serial numbers 5565574 and' 5567459 except carburetors having serial numbers 5566149, 5566150, 5566151, 5566152 and 5567454, were originally sent out with only one diaphragm and due to the fact that a failure of this diaphragm would permit fuel to leak out the venting hole in the cover and thereby create afirehazard besides a loss offuel, later carburetors have been furnished with a reinforcing, perforated diaphragm (Part No. P-61159) assembled on the sprihg side of the other diaphragm. The nerforated diaphrasm has three .028" diameter holes in it to pieverit an air loch between the two diaphragms, which would result in faulty operation of the valve.

1324

CARBURETORS Upon completion of the assembly of the check valve. it should be checked to see that it has the coruect opening t by assembling the check valve in a fixture whereby pressure may be applied to the needle side of ih-e diaphragm and the pressureraised until the needle opens. The opening pressure should be between 20" to 35i' of water. ordering replacement Replacernents-When parts it is necessaryto give complete information concerning the parts desired to avoid delay in shipment, or the receipt of wrong pafts. Whereever possible, the serial number of the carburetor should be given. A careful reference to the assembly drawings (see Figs. 1318 through 1322) to determine the correct part number and name, and if marked with an asterisk (*) giving the size as stamped on the piece, will greatly facilitate service. A specification sheet giving the sizes of jets, fuel level, etc., will be furnished, no charge, if you will write to the Bendix Products Corporation, Stromberg Carburetor Division, South Bend, Indiana, advising the model of your engine. Parts Price lists will also be furnished on request. P-2I200 covers a complete set of gaskets for the NA-Y9C, P-22LL0 for the NA-Y9G and P-60910 for the NA-YgGl carburetor. points of vital imporReassembly-Several tance in the reassembly of the carburetors are: 1. The main body gasket: This should be in perfect condition. If the gasket is torn at any point around the float chamber, it will not only allow fuel to seep out but will seriously effect the mixture control action. If torn around the idle tube, it will cause difficult starting and poor idling operation. 2. Compound or double deck pump: Considerable care should be taken during the assembly of the pump to the carburetor. This operation should be done before assembling the throttle body. The pump leather should be wet with gasoline and one side assembled in the sleeve.

It should be rotated so the leather will go into the sleeve evenly. With the throttle open the operating stem may then be hooked in flace on the pump unit and the two halves of the carburetor assembledtogether in the usual manner. 3. If the venturii have been removed the rubber packing should be replaced before reassembling the carburetor. Make sure that the venturii are down tight with the locating pins in their correct positions so as not to hold the bodies apart. 4. No dirt, shellac or other foreign material should be left in the carburetor. 5. Idle discharge jets: If it was necessary to remove the idle discharge jets to clean and inspect the carburetor they should be assembled in the same holes they were removed from as they are different in the right and left barrel. 6. Auxiliary jet valves: If it was necessary to replace the valves the new valves should be lapped in, using fine lapping compound. The opening point of these valves should be checked to see that they operate properly by placing an 8 lb. weight on the sylphon; this weight should just start the valve towards its seat and a 12 lb. weight should seat the valve. If the valves do not start closing correctly the valves should be checked to seethat they are not binding. Upon completion of assembly the carburetor should be water tested to see that there are no Ieaks from the inside of the carburetor. Plates should be assembled on the intake and engine attachment flanges, the automatic mixture control unit should be assembled and the fuel inlet plugged. By applying 3 to 5lbs. per square inch pressrure, through a connection in one of the plates and then by submerging the carburetor in a tank of water any leak may be found and repaired. Upon completion of all assembly and tests the carburetor should be completely safety wired before installing on an engine.

1325

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BENDIXSTAOilIENGCAlBlnETORCO. SOUTH IEIID, IIIDIAIIA Us.A.

Fig. 1322

1335

INSTRUCTIONS FOR STROMBERG NA.YgE CARBURETORS OVEREAUL Disassembly-The carburetor should be disassembled for cleaning and inspection each time the engine is given an overhaul. After the carburetor has been removed from the engine and the hot spot and air intake or heater taken off, the halves gfthe carburetor may be separated by the removal of the fillister head screws at the parting surface. The economizer needle, pump Sleeveand venturii are held in the tbrottie-body as the bodies are separated. The pump sleev-e should be removed from the operating stem immediately so there will be no-dangei of its dropping and-becoming bent. Rubbei packing is used around the venturii so that if it is founil necessary to remove them, they will have to be driven out by using a wooden plug as shown in Before removing the throttle Fig. 1323-4. valves, mark them so they may be returned to the barrels from which they were removed.

the piece will greatly facilitate service. A specification sheet giving the sizes of jets, fuel level, economizer setting, etc., will be furnished (no charge) if you will write to the Bendix Products Division, Stromberg Carburetor Division, South Bend, Indiana, advising the model of your engine. Parts price lists will also be furnished on request. P-60701 covers a complete set of gaskets for the carburetor.

and Cleanlng-The Inspectlon bodies and all parts should be thoroughly cleaned in gasoline and aII agesblown out with compressed air. Parts which should be inspected for wear are the float assembly, float needle and seat, throttle shaft and bushings, economizer needle, seat and operating mechanisms and the pump stem. All variable parts should be checked to see that their sizes are in accordance with the carburetor specification desired.

When it is necessary to replace the throttle shaft, the lever which operates the economizer should be assembled in accordance with Fig. 1323-8. The throttle valves.'When when in the closed position, should fit tightly. the throttle valves have been fitted, center them in the wide open position. If the economizer operating lever has been assembled at the correct angle, the tbrottle valves should be centered. However. when this work is done in the field. it may be necessary to file the stop at A, Fig. 1323-8, or bend it toward the screwed-in stop.

To disassemble the compound pump unit, it should be removed from the operating stem and the four small hexagon head screws which hold the stem clip in place should be removed. The connecting rod between the upper and lower piston is milled flat above the cross hole, so it can be held with a wrench when removing the center screws. Considerable force will be required to Ioosen the center screw as it has been staked in place as a precaution against its coming loose in service. When the center screw has been removed, the upper piston may be lifted out of the sleeve and the connecting rod and lower piston can be removed through the bottom of the sleeve. Care should be taken that none of the parts are damaged during disassembly or assembl! as they are made to fit with verv close tolerances and a small nick or dent might iause a binding action. Replacements-When ordering replacement parts, it is necessary to give complete information concerning the parts desired to avoid delay in shipment or the receipt of wrong parts. Wherever possible, the serial number of the carburetor should be given. A careful reference to the assembly drawing (Fig. 132a) to determine the correct part number and name and, if marked with an asterisk (*), the size as stamped on

Reaseembly-All headless screw plugs beIow the fuel level should be assembled with shelIac, being careful not to get it on the end of the plug where it will come off and be carried by the fuel into one of the metering orifices. Headless screw plugs above the fuel level and all other threaded parts screwed into the bodies should have a compound of graphite and caster oil put on the threads.

If it is thought necessary to replace a float needle or needle seat it is recommended that both be replaced at the same time as it is very difficult to fit a new needle to an old seat or a new seat to an old needle. In ordering these parts, be sure to give the size of the by- hole in the float needle seat. This by- hole meters the fuel during inverted flight and its size has been determined to meet the requirement of that particular engine and it is, therefore, important that a seat having the proper size by- hole be used for replacement purposes. The float level should be r7(', phts 3/a" and, minus Y6a"below the parting surface, when using fuel of .710 specific gxavity, and is dependent upon the thickness of the gasket under the float needle seat. The level should be checked under the conditions encountered in service as regards the fuel used and the fuel pressure or head at the carburetor. If a fuel pump is used, a pressure at the carburetor of 3 lbs. per square inch (117" gasoline at .710 specific gravity) should be used in checking the fuel level. A gasket Ye" thick should be used first and if the level is not cortect, thicker gaskets should be used to lower

1336

CARBURETORS

the level and thinner gaskets to raise it. A change of |(t" gasket thickness will change the Ievel approximately Y64". The float needle should have at least 9(a" travel. If it becomes necessaryto replace the mixture control shaft or stop, it is important that the stop be located in the correct angular position on the shaft. In order to do this, place a small piece of wood in the slot of the outer valve plate in such a way that it extends through and will fit in the slot of the inner plate. Place the outer valve plate in the carburetor in the open position and the wood key will keep it from turning. Place the shaft and bushing assembly in the carburetor, adjusting the shaft so the screw driver ends fit into the valve, and put in the screws to hold the bushings in place. Slip the washer and stop on the shaft and turn until the full rich stop is against the large head screw. Assemble lever, indicator plate and nut on the shaft. Draw nut up until washer strikes shoulder on shaft; drill and fit pin through stop and shaft. (See assembly drawing (Fig. L324), for section and end view of shaft assembly.) The economizer needle is operated by an eccentric pin which is part of the economizer lever stem. This stem is operated by the throttle through two levers and a connecting link. It is important that the economizer lever be located at the proper angle with the eccentric pin on the economizer lever stem. When replacing the economizer lever stem, use a new economizer lever also. The lever should be assembledso that its center line forms a 90 degree angle with the center line of the eccentriin as shown in Fig. 1323-D. When the lever has'been properly se*t, tighten the clamp screw and drill stem and one side of lever for the Iocating pin. Screw pin into place. The adjustment of the economizer needle valve in the holder and the eccentric pin on the lever determine the position of the lever when the needle is on the seat and, therefore, the throttle opening at which the lever lifts off the seat. This throttle opening is one of the items of the variable specifications or setting in the carburetor and is given on the specification sheet, being referred to as "economizer setting," the figure given being the throttle opening in degrees. By adding L8 or 20 (the angle of the throttle

valve) to this figure, the angle which the throttle valve makes with the horizontal surface of the carburetor is obtained. Several economizer settings are in use and the proper one should be determined from the carburetor specification sheet. The first adjustment is made by screwing the needle in or out of the holder so that when placed in the main body, the distance from the top of the slot to the parting surface will be in accorda4ce with the dimensions as shown in Fig. 1323-Clfor the economizer setting desired. When this has been done tighten the nut and pin the needle as per the instructions given in Fig. 1323-C. The two halves should then be assembledand final adjustrnent made by meansrof the eccentric on the economizer lever. Check the angle between the throttle and the horizontal surface of the carburetor flange when the needle starts to leave the seat. A simple apparatus to check when this movement starts is shown in Fig. 1323-8. It is made by drilling a hole through the center of a Yt6"-L8 plug, large enough to allow the free movement of a piece of tubing about 4" long. Then by taking out the economizermetering jet plug and jet, it is possible to screw in the other plug and push the tubing up so that it rests on the point of the needle. If a slight pressure is put on the tube with the fingers while the throttle is moved, the unseating of the needle will be easily detected. Adjust the eccentric until the correct angle is obtained. When the adjustment has been made, tighten the nuts, being careful not to move the eccentric, and assemblethe cotter pins. When reassembling the compound pump unit, considerable care should be taken so that the parts wiII be concentric to each other and then checked in the body to see that it works freely before restaking the center screw which holds the piston in place. The small hexagon screws should be safety wired after tightening. When assembling the upper sleeve and piston into the sleeve fastened in the body, considerable care should be taken so the leather will not be curled up around the piston. The leather should be wet with gasoline and one side assembled in the sleeve,then as the piston is forced into the sleeve, it should be rotated so the Ieather will go into the sleeve evenly. With the throttle valve open, the operating stem may then be hooked in place on the pump unit and the two halves of the carburetor assembled together in the usual manner.

1337

F

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VENTURI REMOVAL

P-2OI3E FOR I8O VALVES P-I60I7 FOR 20.VALVES

A S P L I T P I N A S SHOWN D R I L L & R E A MF O R P - I 9 O 8 6P I N W H E N LEVER IS IN P O S I T I O NA S S H O W N

t60-t8"SETTINGWITHP-17684LINK | - ltl32"CENTERS r'j P-16004 t- t5/32" r9-2P t" 27-2? t-t/64' 26.-3lo , T 5 2 D R ] L L F O RP - 6 5 6 7 P I N AFTER ADJUSTING. RIVETENDSOF P I N AND FILE FLUSH. PRELIMINARA YDJUSTMENT NEEDLEVALVE OF ECONOMIZER AND HOLDER.

c #2.9DRILL

E

LEVER AND STEM. FITTIT.IGECONOMIZER

Fig. 1323

1339

P-fo24a F/A-zel P- t7604

Fr7423 P-2r453

P -6 0 3 1 2- *60a57-

P-20t4A -tP-2t423

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BENDIX STROMBER6 CAFzuRETOR

COI

Fig.1324

1339

sEcTtoN

2t226 2t225 23

"H_H"-P-2o57e r P_2O595 P-2057A

Fl76l4

FLOAT

ASSEMBLY-

.---"-21?29 rP-6121

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P- 60 462

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P-60541 P-60494 P-r9054 P- 60405

r-- -+F9187

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---

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Fr5503--

SECTION

P-6O419 P'OO4?O

,.,4

"B-8,

P- 21646 P-560 P-19055 P-r904? P- et8S4 P-604tA

60379

roti wu otoarc cArioi( sr! d srat! ftrca

Etr6

CAFzuRETOR

COMPANY

Fig. 1324

xrtt crva

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9ll

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p-ao?ol

1341

TNSTRUCTIONS FOR BENDIX.STROMBERG

NA.YgJ CARBURETORS

OVERIIAUL carburetor should be disI)lsassembly-The assembled for cleaning and inspection at each engine overhaul and any part worn beyond serviceable use should be replaced. All work should be performed on a clean bench and care should be taken to dispose of all lockwires removed during disassembly to insure against any of the small pieces becoming lodged in the carburetor at reassembly. The entire Pressure Operated Economizer and Valve Body should be fiftt removed from the rear face of the carburetor, by removal of the six Elastic Stop Nuts, and carefully set aside. This unit will be treated in detail in later paragraphs. The Link Bolts should now be removed from the Pump Stem and from the upper end of the Link bet',rr,.en Mixture Control and the Cruise Valve. Unscrew and remove the two Bolts which are in the Air Horn and accessible from the bottom and all Elastic Stop Nuts around the flange which hold the Throttle Body and Main Body together. The Throttle Body can now be lifted off but care must be taken to immediately remove the Pump P_iston and Sleeve Assembly from the Pump Stem to prevent it dropping off and being damThe Automatic Mixture Control Unit asd. sf,outd be removed by the use of special Spanner Wrench, T-24977, and carefully set away. CAUTION: THIS UNIT MUST NOT COME IN WITH MERCURY AS THIS

ELEMENT HAS A VERY DESTRUCTIVE EFFECT ON THE BELLOWS. Disassemblv and service of this unit will be treated in separate instruction sheets.

To disassemblethe compound pump unit the four small hexagon head screws which hold the stem clip in place should be removed. The connecting rod between the upper and lower piston is milled flat above the cross hole so it can be held with a wrench when removing the center screw. Considerable force will be required to loosen the center screw as it has been staked in place as a precaution against its coming Ioose in service. When the center scr:w has been removed the upper piston may be lifted out of the sleeve and the connecting rod and lower piston can be removed through the bottom of the sleeve. Care should be taken that none of the parts are damaged during disassembly or assembly as they are made to fit with very close tolerances and a small nick or dent might cause a binding action. The rubber packing rings around the venturii swell, making it necessary to remove the venturii by driving with a plug similar to that shown in Figure L327-A. This packing should be replaced before reassembly.

Before removing the throttle valves, they should be marked to insure their return to the barrel from which they were taken. Care should be taken not to nick the edges of the valves. The Main Metering Jets are accessible frorn the bottom of the carburetor and the Economizer Metering Jet from the right side. After removal of the Hex Head Jet Plugs the jets can be disassembled by the use of Metering Jet Screwdriver T-24923. The Cruise Valve Metering Jet is accessible from the bottom of the carburetor, under the rear float chamber, by the removal of its Hex Head PIug and the use of the same screwdriver used on the other jets. In order to remove the Float Needle Seat, the small Iock clip must be disassembledand special socket screwdriver, T -L9276,must be employed. Removal of the Diaphragm Pump Check Valve is accomplished by the use of Special Socket T-25075. All other main body parts and plugs may be removed. bodies and all Inspeotlon and Cleanlng-The parts should be. thoroughly rinsed in gasoline and all ages blown out with compressed air. Following parts should be inspected for wear: Float assembly, float needle and seat, throttle shaft and bushings, mixture control and cruise valve stems, and the pump stem and leather. Check all variable parts (jets, bleeds, etc.) to see that their sizes are in accordance with the proper carburetor specification. ordering replacement Replacernents-When parts it is necessaryto give complete information concerning the parts desired to avoid delay in shipment or the receipt of wrong parts. Whereever possible the serial number of the carburetor should be given. A careful reference to the specification sheet and the assembly drawing (Fig. 1330) to determine the correct part number and narne. and if marked with an asterisk (*) the size as stamped on the piece and listeil on the specification sheet, will greatly facilitate service. A specification sheet giving the sizesof jets, fuel level, economizer setting, etc., will be furnished (no charge) if you will write to the Bendix Products Division, Stromberg Carburetor Division, South Bend, Indiana, advising the model of your engine. Parts price lists will also be furnished on request. P-61163 covers a complete set of gaskets for the NA-Y9J. Reassernbly-All headless screw plugs below the fuel level should be assembled with shellac, being careful not to get it on the end of the plug

1342

CARBIIRETORS where it may come off and be carried by the fuel into one of the metering orifices. Headless screw plugs above the fuel level and aII other threaded parts screwed into the bodies should have a compound of graphite and castor oil put on the threads. When it is necessary to replace the throttle shaft the new style shaft, bearing the same part number but having a larger diameter (%2't instead of rYn") at the point where the throttle stops are assembled, is used. It will also be necessary to use a new throttle stop P-61285, a new washer, P-61288, new pump -0 lever and stop assembly, P-61283 and No. taper pins instead of the No. 0000 size. The throttle stop should be assembledto the throttle shaft in accordance with Figure 1327-Ei. The throttle valves should fit tightly when in the closed position. After the throttle valves have been fitted turn them to the wide open position. The wide open throttle lever stop- arni should just touch the screwed-in stop in this position; if not, either fiIe a little off point "A" as shown in Figure L327-B or bend the stop towards the screwed-in stop. Leaving the valves in the wide open position with the throttle stop against the screwed-in stop, assemble the pump lever with its_stop against the screwed-in stop at the pump side of the throttle body and clamp securely. The shaft can now be iurned froni the wide open position and the pump lever drilled, reamed and pinned with a No. 0 taper pin. If it is thought necessary to replace a float needle or needle seat it is recommended that both be replaced at the same time as it is very difficult to fit a new needle to an old seat or a new seat to an old needle. In ordering these parts be sure to give the size of the by- hole in the float neldle seat. This bv-pais hole meters the fuel during inverted flighf and its size has been determined to meet the requirement of that particular engine and it is, therefore,, important that a seat having the proper size by-iass hole be used for replicemenl p'urposes. The float level should be rZ" plus V6a"minus W" below the parting surface, when using fuel of .710 specific gravity, and is dependent upon the thickness of the gasket under the float needle seat. The level should be checked under the conditions encountered in service as regards the fuel used and the fuel pressure or head at the carburetor. If a fuel pump is used, a pressure at the carburetor of 3 lbs. per square inch (L17" gasoline at .710 specific gravity) should be used in checking the fuel level. A gasket Ye" thick should be used first and if the level is not correct use thicker gaskets to lower the level and thinner gaskets to raise it. A change of %," gasket thickness will change the level approximately Y6a". The float needle should have at

least Y6a"travel. A conveniently located fuel level test hole will be found on the left side of the main body just below the parting surface and ahead of the needle valve chamber. Bv removing the /s" pipg plug from the slopin-g hole the fuel level can be observed without disassembly of the carburetor or removal from the englne. If it becomes necessary to replace the mixture control shaft or cover assembly it is quite important that the stop be located in the correct angular position on the shaft. All parts should first be assembled and grease should be applied between the Iatch plates to insure against their sticking or binding in service. The cover should be turned on the shaft until it rests against the "Automatic Lean" stop. Without moving the cover rotate the shaft until the slot in the end of the shaft lines up with the upper screw hole as shown in Figure 1327-C. Put on the lever and clamp securely by tightening the nut. Insert the valve plate in its proper location, put the cover on the carburetor and fasten temporarily with two screws. Rotate the mixture control 38' clockwise to the "Manual Full Rich" position. Carefully remove the cover and note the valve plate. Both "Manual FulI Rich" ports should be open as shown in the uppe{ half of Figure 1326 (52). The cover may now be pinned to the shaft by drilling a No. 42 hole, reaming for a No. 0000 taper pin and inserting the pin as shown in Figure t327-L. The inner valve plate screws should not be removed unless the plate is being replaced. The new plate should be assembled with shellac as a seal against leakage and finally lapped with fine grinding compound. If the Cruise Valve and Primer stem shows signs of excessive wear it should be replaced. The new stem, bushing, packing, washer and lever may be assembled as a unit and inserted into the cover later. The slots in the end of the stem should be set at an angle of 30" to the lever and the lever clamped tieht. Check thoroughly with Figure .1327-D,to Jeethat the assembly is correct before drilling and pinning, as correct functioning of the carburetor depends conside_rably on the exactness of the- assembly angles. When reassembling the compound pump unit considerable care shoda be tiken so ttrit the parts wiII be concentric to each other and then checked in the body to see that it works freely before restaking the center screw which holdi the prfton in place. The small hexagon screws should be safety wired after tightening. When assembling the upper sleeve and piston into the lower sleeve fastened in the body, be careful that the leather is not curled back around the piston. The leather should be first wet with gasoline and one side assembled in the sleeve,

1343

FLOAT CHAMBER (t)

LEVER(I FULCRUM ( ECONOMIZER OPERATED BY MANIFOLD PRESSURE.

TO BLOWER RIM MANIFOLD PRESSURE

DASHPOT(t7)

EVACUATED BELLOWS(r3) 4'

(r4) SPRTNG ECONOMIZER

ECONOMTZERSTEM (r8)

c

ECONOMTZERVALVE (

ECONOMIZERVALVE

ovER-RrDE SPRTNG 0g)

CRUI METER

NA-YgJ CARBL FULL POWER PO

Fig. 1325

l3{3

MAIN AIR BLEEO (5)

MAIN DISCHARGE

NozzLE (6)

MAIN METERING JErS (2)

cRUrsEvALvE (24)

ECONOMIZER METERTNGJET (l2) CRUISE VALVE M E T E R I N GJ E T

A_YgJ CARBURETOR FULL POWER POSITION Fig. 1325

1345

CARBIIRETORS then as the piston is inserted into the sleeve, it should be rotated so the leather will go into the sleeve evenly. The Automatic Mixture Control Unit should be overhauled and correctly set in accordance with the instructions covering that unit. Check to see if aII parts are now properly assembled to the two bodies; make certain that the automatic mixture control unit is fastened to the throttle body and lockwired, etc. The main body gasket should be carefully put in place over the main body studs. Rotate the piston so. that the opening of the piston b*p iovei is pointed directly toward the center of the left throttle bore and raise it in the sleeve

as high as possible without pulling it out. Take the throttle body and place the valves in the wide open position. This extends the pump stem as far as possible to facilitate assembly. The throttle body should now be turned over and the automatic mixture control unit carefully lowered into its well in the main body. When the end of the pump stem is close enough to the pump piston cover carefully engage them bv a counter-clockwise rotation of the entire tfuottle body. The two bodies may now be pushed together, fastened at the flange in the usual manner and the two through bolts assembled in the air horn. The mixture control link should now be assembled and all parts securely lockwired.

PRESSURE OPERATED ECONOMIZER UNIT The pressure operated economizer unit is composed of an evacuated sealed bellows which reep6nds to manifold pressure changes to actuale an economizer valve or enrichment device, a dash-pot to stabilize the action of the bellows, and a balibrated spring to offset the force of the evacuated bellows and to provide the necessarv valve travel. This unit should be disass6mbled and overhauled at each regular engine overhaul and the greatest care should be exCrcisedirr this work to see that no parts are damaged in any way. After removal from the carburetor the unit may be serviced as follows: Dlsaseernbly for Overhaul-Disassembly of the unit may be accomplished according to the following procedure and by referenceto Fig, i1332: 1. Remove the six screws from the top and take off the cover. 2. Cut the lockwire and unscrew the nut holding the economizer needle assembly to the actuating lever. It is best not to disturb the nut and locknut on the economizer needle assembly resting beneath the actuating arm as these determine the needle opening point and setting the adjustment wiII be much easier if the original adjustment is retained. 3. Unscrew the special plug from the bottom of the valve housing and by the use of the socket, T-25076, remove the economizer seat and needle valve assembly. Extreme care should be exercised to prevent bending the needle which, if distorted, will bind and not seat properly. 4. Separate the valve housing and the economizer unit housing by the removal of the hex nuts at the parting surface. 5. Remove the spring cup at the bottom by pressing it in and turning one-fourth turn. Do not allow the spring to snap

out suddenly as it may kick the spring retainer against the bellows and damage the thin metal waII of this unit. It is recommended that the spring not be rcmoved from its guide nor the adjustment of the spring adjusting screw on the actuating lever be lost as these determine the rate of needle travel. Considerable time can be saved if the original adjustment be retained. 6. Unscrew the two fulcrum pin plugs on either side of the housing, loosen the lever set screw and remove the lever fulcrum pin. 7. Remove the three screws from the bottom of the housing which fasten the dash-pot to the economizer body casting, unscrew the bellows nut and then the lever assembly, together with the dash-pot and evacuated bellows, can be lifted from the top of the housing. If the bellows and dash-pot clevis pins are tight enough to require driving out, slide the lever assembly to one side of the clevises, insert enough shims to fill the clevis solid and drive the pin out. This will prevent distortion of the clevis. 8. Examine the bellows assembly very czuefully to see that it has not been damaged or corroded. No attempt should be made to reseal the bellows if it is found to leak as repair of this part requires very special equipment and should be done only at the factory. The bellows is comparatively delicate so that it should be handled very carefully. As mercury has a very corrosive effect on this unit be certain that it does not come into with this element. washing all parts in clean Reassernbly-After sasoline, blow them off with air. The ball bearings in the fulcrum pin plugs should be

1346

CARBURETORS flwhed with a Iight mineral oil of about S.A.E. 10W grade or its equivalent to prevent rusting after which a small quantity of high grade light greaseshould be worked into the bearing. L. Replace the dash-pot diaphragms at each engine overhaul and since this unit must be completely filled with Triethylene Glycol C.P. all the dash-pot parts should be immersed in a container of this fluid and should be completely assembled while beneath the surface of the liquid in order to prevent any air being trafped within. Be sure that the parts are lined up correctly so the diaphragm holding the clevis and piston will not be twisted during final assembly of the economizer. 2. Attach the dash-pot assembly and bellows assembly to the lever assembly with the clevis pins and cotter. The bellows assembly should be so mounted that the locating-pin hole on the bottom is on the side opposite the dash-pot. It will generally be necessary to insert shims between

the clevises and lever to prevent distortion of the clevises when the pins are reinstalled. 3. Place the economizer spring plate in position on the bottom of the housing, set the spring retainer and guide in its approximate location, carefully lower the lever assembly with the dash-pot and bellows into their respective locations and fasten them tightly. 4. Reassemble the fulcrum pin and set screw. Screw the fulcrum pin plugs into place and check for end play. There should be from .008" to .016" end play at this point. This may be adjusted by using gaskets of different thickness under the hex head plugs. 5. Rgplace the spring, guide and spring cup. The cup should be carefully pushed into the opening, turned 90o and released. Be certain that it is properly seated and not riding on the retaining shoulder.

TESTING TEE ECONOMIZER As safe and economical performance of the NA-Y9J earburetor is controlled to a large extent by the pressure operated economizer unit too much stress cannot be laid upon its proper Equipment setting and perfect functioning. used both for testing and adjusting this unit is illustrated in Figure 1328. Rste ol Needle Travel-The economizer unit assembly should first be tested for rate of needle travel. This rate should be .030" plus or minus .0005" per inch of mercury. Equipment used and manner of setting-up is shown in the upper right section of Figure 1412. The cover of the pressure operated economizer (25) should be reinoved beiore performing the following operations: 1. A special stem assembly (23) should be assembled to the economizer operating arm at the point where the needle stem is ordinarily attached. The Iower nut on this special stem (23) is assembled and fastened at a specific dimension from the end of the stem in order to give a definite relationship between the lever arm and the face of the test block (22). (Dimension "B", Figure,1329.) 2. Mount the test blodk (22), and a standard r/s2" gasket, on the flange of the economizer (25) with the same nuts used to attach it to the valve housing. Screw /a" hose nipple (24) and 11" hose nipple (26) into the manifold pressure connection boss and into the cover of the economizer respectively as shown. Mount an Ames No. 88 dial gauge (21) with spring removed to the test block (22) with a dial gauge bracket (20).

3. The lever arm should be adjusted to its proper position by turning the adjusting screw over the spring guide. This position of the lever arm may be determined by reading the existing barometric pressure then finding the corresponding dimension "B" for this pressure on Figure 1329. For instance, if the barometer reads 29" the dimension from the bottom of the stem to the bottom face of the test block should be .235'. A tolerance of plus or minus .010" may be allowed on this dimension. 4. Assemble the cover of the economizer (25) and attach a rZ" hose from nipple (24) to the vacuum and pressure outlet (16) and a second hose from the )1" hose nipple (26) to the top of the 30" single leg mercury manometer (28). Place the assemblyon the holder block (27). 5. Slowly open the vacuum valve (10) until the mercury column shows a pressure of 24" of mercury absolute. The bleeder valve (17) should be used for fine adjustment. The absolute pressure is the pressure measured above that of a perfect vacuum. The barometric pressure is absolute pressure ed generally in inches of mercury. Therefore, to obtain the correct reading on an open end mercury manometer, the difference between the existing barometric pressure and the desired absolute pressure should be ed on the open end manometer. If the absolute pressure is higher than the existing barometric pressure, air pressure will have to be used, but if the absolute pres-

-l L347

RELATIVE POSITIO CUT-OFFCLOSED

rIDLE T |ULE

CUT-OFF L U r -(Jr r L CLOSED L(JSLU

AUrooPEN

.PEN A-AUro

,o*Yi{

ytlyt^L .\vp-l cuoseo<\!$/

/

oPE

PUMPOPEN PRT I MMEERR

PRIMER CLOSED

(so)

cLosED

CRUISEVALVE OPEN

AUTOMATIC LEAN AGAINST STOP COUNTERCLOCKWISE

(

x cRUlsE UALVE/ ' OPEN

(st)

AUTOMATIC RICH I8'CLOCKWISE

MANIL

38"

IDLE CUT-OFF AGE 6

rDLECUT-OFFHOLE (4

AUTOMATICMIXTURE CONTROLVALVE

REAR MANUAL MIXTURE CONTROL HOLE (4 INNER VALVE PLArE (4 LOWER MANUAL MIXTURE CoNTROL HOLE (46

sucrroN NozzLE RESrRtcrloN(32

sucroN NozzLE(31 AIR INTAKE

NA*Y9-

MIXTURECON

Fig. 13

3{;

IV5 POSITIONS OF CONTROL VALVES

'";il=&J FF cl-oSED

MANUAL

rIDLE CUT-OFFCLOSED

CU.r-OFFCLOSED

AUTO.CLOSED

AUTO. CLOSEO

,,{'-4V-.] -D

opEN<.-\

MANUAL

I

OPEN

PUMP OPEN

)PEN

RIMER

TOSED RI]ISE VALVE EN

AUTO C L O S E D

MANUAL CLOSED

cLosED

/

IDLE CUT-OFF O P E N

PUMPCLOSED

PRIMER CLOSED

PRIMER CLOSED

CRUISE VALVE

CRUISE VALVE CLOSED

OPEN

(sg)

$z) MANUAL FULL RICh 38' CLOCKWTSE

MANUAL FULL LEAN

80'cLocKWtsE

PRIMER OPEN

IDLE CUT-OFF & PRIMER

90" cLocKwtsE

AGAINST STOP

TO REAR FLOAT CHAMBER FRONT FLOAT CHAMBER (37)

FLOAT

AUTOMATIC M I X T U R E CONTROL U N I T

AKE

NA_Y9-I CARBURETOR M I X T U R EC O N T R O LA N D I D L E C U T _ O F F

Fig. 1326

1349

CARBURETORS sure desired is lower than the barometric pressrure, vacuum should be used. For instance, if it is desired to rcg1ster 24" absolute pressure and the existing barometric pressure is 29.2", we subtract 24" from 29.2" and find the difference is 5.2" which will have to be ed on the open end mercnry manometer. Since t}ne 24" absolute pressure is lower than the 29.2" barometric pressture,the5.2'of mercury must be vacuum. Note the Ames No. 88 Dial Gauge (21) reading at24" mercury absolute pres{rure but before taking the reading tap the economizer (25) several times with a small fiber mallet. Close the vacuum valve (10) and take the Ames reading at atmospheric presrilrre. Transfer the hose from lhe top-of the mercury manometer (28) to the bottom or weII (to pressure) and leaving vacuum valve (10). closed, open au presnurevalve (11) and take Ames dial gaugb readings at several intervals up to 48" mercury absolute. 6. The rate of travel of the needle should now be computed by dividing the travel between the various points by the number of inches of change in pressure and if it proves to be less than .030" plus or minus .0005" per inch of mercury the spring cup should be removed and the spring unscrewed somewhat from the screw and guide. The reverse procedure should be used if the rate proves to be too high. 7. When the number of coils on the spring guide and screw, are changed it becomes necessary to readjust the screw above the spring to obtain the correct dimension r$tr.- After this the rate should be rechecked. 8. After the Pressure Operated Economizer (25) has undergone test for rate of needle travel it should be removed from the holder block (27) and the test equipment (20), (2L), (22), (23), and (24) removed. Leave the one nipple (26) installed. Reaseembly of Eoonomlzer Unlt to Carburethe economizer packing in its recess tor-Insert in the top of the Economizer Valve housing, add the gasket and fasten the Economizer Unit to the Valve Body with the five hex nuts and washers provided. Now screw the economizer needle aid seat into place, guiding the end of the needle stem through the hole in the end of the operating arm and fasten with the nut. It may be necessary to assemble more than one washer under this castle nut to raise it high enough to lock-wire it to the end of the stem. Replace the cover. The entire unit and valve hotising may now be assembled to the carburetor.

Preparlng Carburetor lor Further Econotest set-up as sketched in mlzer Tests-The the main part of Figure 1328 is used in all following tests: 1. Remove the main, economizer and cruise valve metering jets and replace with blank jets. Plug the fuel inlet boss. 2. Remove the hex head plug from the economizer unit cover and insert gauge holder (39). Assemble an Ames No. 88 dial gauge (32) (with the spring removed) together with gauge extension (40) into the gauge holder (39) and fasten with the gauge clamp (37). 3. An air hose can now be attached from vacuum and pressure outlet (16) to the manifold pressure connection on the unit hose nipple (19), LA" pip through f" tee (36) and. rf" close pipe nipple (35). A second hose is connected ftom the rfi" pipe tee (36) to the top of the Ames No. BA aiA daube (32) wliere it is attached by hosefitting (31). 4. Remove the plug from below the economizer needle valve and replace with the adapter elbow (33), the regular gasket (41) and a /2" hosr-fitting (34) from which a L/2" hosr- (9) runs to air valve (4). 5. In order to secure exact readings and to overcome . any slight sticking tendencies of the moving parts a pneumatic vibrator (29) is attached to the carburetor flange with a (30) vibrator plate and is connected to the air source through the air pressure valve (18). test should be made for Leakoge Test-A Ieakage from the pressure operated economizer unit tlo the float cliamber of ihe carburetor past either the needle or the seat. Leakage of this type will cause the carburetor to flow erratically. 1. Connect a rZ,, hose from the r/,, hosrnipple (38) on the economizer to the Weil or Bottom of the 30" single leg mercury manometer (28).. (This wiU, regrste.r air pressure greater than atmospheric air pressure.) Open the air valve (4) so itrat it c6nnects the manometer (2) to the testing hose (9) but not to the air adjusting box. Set the carburetor mixture con"Manual FulI Rich" position. tr6l in the Open the air pressure valve (18) to start the pneumatic vibrator (29). 2. Slowly open the air pressure valve (11) until the mercury manometer (28) s a pressureof 38" of mercury absolute. (Barometric plus manometer reading.) Care must be taken not to open the air pressure valve (11) either so far or so rapidly that the mercury is blown out the mercury tube.

1350

CARBURDTORS 3. The water column in water manometer (2) should be observed closely while the mixture control is rotated from the "Manual Full Rich" to the "Manual Full Lean" position. If a slight rise in the water column is noticeable, a leak is present and the rubber packing around the seat between the economizer body and the valve housing should be replaced. economizer is set to open Openlng Pollt-'The at a predetermined engine manifold (blower rim) pressure rather than at a set throttle valve -position as in the conventional carburetor. The i,p"trirg point should be checked and set as follows: 1. Determine from the carburetor specification sheet whether the economiZer will start to open above or below the existing barometric pressure. If it wiU open below connect the hoqe from the r/" l{o* nipple (38) to the TOP of the nnercury manofnglgl (r.Q. (Exactly as shown iir Figure 1328.) If the opening point is found to be above the existing barometric pressure the hose should be attached to the bottom or well of the mercury manometer (28). 2. Turn air valve (4) so that the water manometer (2) is connected to the air adjusting box but not to the air hose (9). The air bleeder (6) should be a No. 5 and the air valves (5), (13), (14), should remain closed. 3. Open tlre air pressure valve (1) allowing air to flow into the surge tank (15) and by means of the air pressure reducer valve (8) adjust the air pressure to about 8-10 pounds pressmre on the dial pre$ilue gauge (3). Slowly open the air adjwting needle (12) until the water column in the water manometer (2) stands at 42.4". Start the pneumatic' vibrator

(2e).

4. Turn the air valve (4) to connect both the hose (9) and the water manometer (2) to the air adjusting box. If the economizer needle is closed the water column will not change but if the needle has started to open the water column will drop. The water column should start to drop from the 42.4" point just as the absolute pressure in the economizer exceeds the absolute pressure listed on the carburetor specification sheet as the economizer setting. For instance, if the economizer is to open at 27.5" and the existing barometric pressure is 28.6" the needle

should just open al_tlg qressyle in the economizer reaches 27.5" abs. (1.1" reading of the mercury manometer) and the water column will start to drop. 5. If the needle opens at too low a pressure remove the cover of the economizer, and screw the needle up through the lever, then reassemble the cover and recheck the point. If it opens too high, the needle should be screwed down. Over-rlde-After adjustment of the economizer opening point is completed the economizer valve over-ride spring opening should be checked. 1. The same equipment and set-up employed in the previous test should be used. The water column should be set to 42.2" and then the air valve (4) opened to the hose (9), water manometer (2) and the air adjusting box. 2. The vacuum valve (10) should be slowlv opened and the watei c6lumn in the wate-r manometer (2) closely watched. The height of the mercury column in the mercury manometer (28) should be observed when the water column starts to drop. This drop indicating the over-ride opening should take place between 10" and 15" of mercury absolute pressure. If the spring operur outside these limits it should be replaced. Rate of Travel Check-The rate of needle travel should be hastily rechecked after the economizer has been tested and adiusted. It will be necesszuyto check the rate oniy from the opening point up to 38" of mercury absolute. The gauge extension (40) rests upon the operating lever directly above the bellbws and as the distance from this point of to the fulcrum pin is just 1/3 the distance from the needle to the fulcrum pin the rate of travel should be divided by 3 to obtain the correct reading on the Ames dial gauge (32). If the readings obtained by this check do not coincide with those made on the test block the needle and seat should be closelv examiried for distortion or for any particles of foreign mattgr which would tend to causea binding action. When all checks have been completed, the cover should be removed and the spring and needle adjusting screw locknuts carefully tightened and lockwired. All blank jets previously inserted in the carburetor should be replaced with the proper size metering jets and the carburetor completely assembled.

1351

N A - Y g J V E N T U R I R E M O V A LP L U G SPLIT PIN A5 SHOWN * 2 9 { . 1 3 6D) R T L LA N D R E A M FOR 1+OTAPER PIN PIN P-6I284 IN POSITION SHOWNWITH P-I9273 PIN

P-0t2e5

THROTTLE SHAFT ASSEMBLY

B. +az (osss)DRTLL AND

WHEN LEVER POSITION HAS BEEN DETERMINED,

REAM FOR +OOOO TAPER PIN. ASSEMBLE PIN P-Ig086 AND SPLIT END AS SHOWN.

+az (.os:s)onul aruo

+IOOOO 8EAM FOR TAPER PIN. ASSEMBLE PIN P.I4577 AND SPLIT END A5 SHOWN.

W H E N N E C E S S A R YT O CHANGE MIXT. CONTROL SHAFT END PLAY USE WASHER +61225 I N S T E A DO F P - 6 0 9 5 8

(eruoprav ro BE bos-.ozo)

Y GREASE BETWEEN PLATES AT ASsEMBLY

sET SLOT ON c OF

r sLor oN { oF

SCREW HOLE AND CLAMP LEVER P-6IO92 ATANGLE OF 3OO A5 SHOWN

S C R E WH O L E W H E N P-6il25 15 AGATNST AUTOMATIC STOP A5 SHOWN

c. M I X T U R EC O N T R O L C O V E RA S S E M B L Y

?no

D

C R U I S EV A L V EA N D P R I M E RC O V E RA S S E M B L Y

NA-YgJ CARBURETOR Fig. 1327

1353

@oral

tI

PRESSURE

@nrnVALVE @nrnVALVE

T]

@vN

@",-

t{l ffi

@arn @nrn BLEEDER,' ' ''' GlvE-t l i / ^ " ' PnEssune 1-@aia \

\

)@arn \----@AIR

A D J U S T N GN E E D L E VALVE

AIR VALVE

@arn sURGErANK

@nrn PRESSURE

AIR PRESSURE

Fig.1328 TESTING

AND SETTING

l 353

T-24996 @va nose NTPPLE

@ n o l o e n B L o c Kr - 2 5 o 6 s

30" SINGLE LEG MERCURY MANOMETER

PNEUMATIC VIBRATOR

ourLEr @vacuuv ANDPRESSURE

VIBRATOR PLATE

@ e,-eeoenvALVE

HOSE FITTING T.25070 "88 AMES DIAL GAUGE T-25045

GAUGE CLAMP T-24995 I/4 HOSE NIPPLE

r-24996 GAUGE HOLDER T-24994 GAUGE EXTENSION T-25066

I:SE

-.7

y41yE-----z

GASKET C:SSURE VALVE D-USTING NEEDLE ATVE

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CARBURDTORS TABLD OF CLEARANCDS NAME CruiseValve Movable Plate Pilot and ReamedFixed Plate CruiseValve Stem and Bushing. CruiseValve Link and Link Bolt. EconomizerNeedleand Seat. Economizer Needle Ball ts, End Play Each. Economizer Spring Retainer Stem and Guide Economizer Dash-pot Piston and Sleeve. Economizer Dash-pot Piston Ball t End Play Economizer Ball Bjearingsand Clevis Pins. . Economizer Ball Bearings and Fulcrum Pin. . . Economizer Clevis Pin and Dash-pot Clevis. Economizer Clevis Pin and Bellows Clevis. Float Bearing and Fulcrum Pin. . . Float Bearing End Play.. Float Pin and Needle Slot. .

Float Needleand Seat Guide Float Seat and Inverted Flight Valve. Float Level Mixture Control Movable Plate Pilot and ReamedFixed Plate. . . . Mixture Control Stem and Bushing. Pump CheckValve Needleand Seat Guide. Pumb Link and Link Bolt. Pump Link and Link Pin. Pumb Stemand Bushing. Pump, Upper Piston and Sleeve. Pump,Upper PistonGrooveand Ring (Width) Pumb,PiitonRingGap. ..... UpperSleeve. Pumi'Piston Rodtin R-eamed Thro^ttleShaft and Bushings. .. .'. . Throttle Shaft and Bushings,End Play

CLEARANCE Desired Max. .0040 L .0100 L .0020 L .0070 L .0017L .0100 L .0025 L .0008L .0005 L .0010 L .0050L .0010 L .00.20L .0060 L .0010 L .0020 L .0050L .0005 L .0010 L .0050L .0006 T .0001 T .0040L .0006 T .0001 T .0030L .0012 T .0001 T .0020L .0012 T .0001 T .0020L .0010 L .0030 L .0090L .0043 L .0120 L .0240 L .0100 L .0200L .0070 L .0120L .0030L .0050 L .0020L .0030 L .0080L As Spec. +344-144 .0010 L .0020 L .0100L .0010 L .0020 L .0070L .0025 L .0010 L .0080L .0007L .0017L .0100L .0015L .0020L .0080L .0010L .0020L .0080L .0120L .0045 L .0C65L .0010L .0015L .0060L .0010L .0030L .0150L .0005L .0015L .0080L .000?L .0015L .00?0L .0L20 L .0160 L .0400L Min. .0020 L .0010 L .0007 L .0006 L

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1361

INSTRUCTIONS ON BENDIX-STROMBERG AUTOMATIC MIXTURE CONTROL UNITS DESCRIPTION The Automatic Mixture Control Unit is a metallic bellows responsive to variations in temperature and pressure, operating a contoured valve. It is used to maintain the correct fuel/air mixture ratio in a carburetor operating under conditions of varying air temperature and pressure, such as result from changes in altitude. This is accomplished by the unit automatically varying the metering pressure on the jets to furnish a flow of fuel proportional to the mass air flow to the engine. The sealed metallic bellows is filled with nitrogen and an inert oil. The nitrogen provides the temperature response; the oil dampens vibration. As the density changes, the bellows expands or contracts moving the tapered needle inlhe seat, which changes the size of the orifice and regulates the flow of air past the unit, thus controlling the effective metering pressure on the jets. The Automatic Mixture Control Unit is used on all models of Bendix-Stromberg Injection Carburetors and many of the float type. The Unit is furnished in several types having vari-

ations in the covers, screens, size of the threads on the mounting bases, and different tapered needles. The same bellows are used in all types. The tendency of flexible metallic bellows of Iow hysteresis to respond to engine vibration frequencies has been eliminated by the construction shown. The inner diameter of the bellows is given a small clearance around a cylindrical center sleeve and the space between is filled with a measured amount of chemically inert fluid having a low viscosity change with temperature. Under vibration each convolution of the bellows acts as a dash pot, both hysteresis and synchronous vibration are eliminated, and the endurance of the device in service has proven quite satisfactory. The bellows and springs are carefully calibrated to insure the proper response rates. The valve points are specified by letter and number to designate their taper. The complete calibrated unit is a self-contained assembly which is screwed into the throttle body.

OVEREAUL The overhaul work done on this unit should be in strict accordance with the instructions contained herein. following procedure should Dlsassembly-The be used in disassembling the mixture control unit. Refer to Fig. 1333. 1. Take off needle adjustment lock nut (9). 2. Loosen the spanner nut (14) with T-24977 spanner wrench. 3. Unscrew housing (3) from the bushing (15). 4. Unscrew the bellows assembly (4) from the housing (3). 5. The snap ring (12), which retains the needle (16) in the bellows assembly (4) should be removed with a pair of longnose pliers. This will allow the needle retaining washer (11) and the needle (16) to slip out of the bellows assembly (4). When the bellows (4) is free, it should be put in a secure place where it will not be injured in any way. As per9u5,r has a very corrosive effect on the bellows, be sure that this element does not come in with it. aII of the parts Inspeotlon of Parts-After have been carefully cleaned with gasoline, blown off with compressed air, and carefully dried, the parts should be inspected as follows:

1. Examine the bellows assembly (4) very carefully to see that it has not been damaged or corroded. The felt washer (5) shown on Figure 1333 should be stuck to the bottom of the bellows assembly (4) with shellac. No attempt should be made to reseal the bellows if it is found to leak as this requires very special equipment and should be done at the factory only. 2. It is recommended that the Formica Bushing (6) be replaced if the clearance between it and the inside portion of the bellows assembly (4) exceeds .020". 3. The needle (16) should be examined to see that it is in good condition, and a good fit in the bushing (15). If the clearance between the needle and bushing exceeds .002" the needle or possibly the needle and bushing should be replaced. The needle should be well polished. 4. The screens (10) and (7) should be examined to see that they are not clogged or broken. Reassenbly-After the parts have been carefully inspected the unit should be assembled in the following manner. Refer to Fig. 1333.

t362

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NEEDLE ADJUSTMENT LOCKNUT

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o

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WASHER

Fig. 1333- Automatic Mixture Control Unit

1. The Needle (L6), the Needle Retaining Washer (11), and Snap Ring (12) should be inserted in their correct order into the inner diameter of the Bellows Assembly (4). 2. Screw the Bellows Assembly (4) into the Housing (3). 3. Assemble the Needle Adjustment Lock Nut (9) onto the top threaded portion of the Bellows Assembly (4). 4. Screw the Spanner Nut (14) on to the Housing (3) as far as it will go. 5. Put the Calibration Spring (13) over the Needle (16) and make certain that the Felt Washer (5) is fast to the bottom of the Bellows Assembly (4). 6. Slip the Screen (7) in place in the Bushing (15). 7. Now screw the Housing (3) into the Bushing (15) until it is tight, then tighten the Spanner Nut (14) against the Bushing (15). 8. Put a new Neoprene Packing (8) in place and assemble the small Fillister Head Screw and Washer to the top of the Housing, which will be used later for lockwiring the Needle Adjustment Locknut (9). 9. Do not use any oil on the needle for lubrication as this is likely to collect dust which

will causethe needle to become gummy and stick. Checklng Needle Travel-After the unit has been overhauled it should be checked to see that the needle travel is correct for changes in pressure. Figure 1334 shows the equipment which is necessary for checking this travel and also for setting the automatic mixture control at altitude. In order to obtain accurate settings which are comparable to the factory settings it is recommended that equipment exactly as shown on Figurei 1334 be used for testing and setting the Automatic Mixture Control Unit. Complete information on this test equipment will be gladly furnished on request. 1. The Automatic Mixture Control Unit (7) should be assembled on the Indicating Stand (6) in the inverted position as shown and an Ames No. 88 Dial Gauge (5) should be attached to a bracket on the Indicating Stand (6) so that the bottom leg rides on the end of the Automatic Mixture Control Needle. The Ames No. 88 Dial Gauge should have the Tension Spring removed so there will be as little pressure on the Mixture Control Needle as possible. 2. We as,sumenow that the Adjusting Stand (4) is removed from the Altitude Chamber (13) and the Air Exhaust Connection

CARBURETORS (8) and Air Intake Connection (9) are plugged. Now place the Indicating Stand (6), with the Automatic Mixture Control Unit and Ames Dial Gauge assembled, into the Altitude Chamber (13).

3 . A Pneumatic Vibrator (20) should be at-

tached to the top of the Altitude Chamber (13) as shown and this should be started by opening the Air Pressure Valve (31).

4 . Connect the top of the 30" Single Leg Mercury Manometer (30) to the nipple on the top of the Altitude Chamber (13) with a /a" rubbet hose so the vacuum in the Altitude Chamber will be ed on the Mercury Manometer (30). 5. Close the door of the Altitude chamber (13) and adjust the vacuum valve (23) and adjustable bleeder (2L) until the vacuum in the altitude chamber (13) which is ed on the mercury manometer (30) is equivalent to 28" of mercury absolute. NOTE: The absolute pressure is the pressure above that of a perfect vacuum. The barometric pressure is absolute pressure ed generally in inches of mercury. Therefore, to obtain the correct reading on the open end mercury manometer (30) the difference between the existing barometric presf[rre and the desired absolute pressure should be ed on the open end manometer (30). If the absolute presfrure is higher than the existing barometric pressure, air pressure will have to bq. used, but if the absolute pressure desired is lower than the barometric prassurg, vacuum should be used.

6. Record the Ames Dial Gauge reading at28"

of mercury absolute pressure. The Ames Dial Gauge readings at 23", 16", 13" and 10" of mercury absolute presgure should also be recorded.

7. To find the actual travel of the Mixture Control Needle, the Ames Dial Gauge reading. at 28" absolute pressure should be subtracted from the Ames Dial Gauge readings taken at the other four absolute pressures. This will give the travel from the 28" absolute pressure point to the other four points. The travel of the needle should be checked to the curve on Figure 1335 to see that it is between the low lirnit andhigh limit curves. 8. If the needle travel does not come within the limits shown on Figure 1335 the needle should be checked to see that it is not sticking or binding or a new spring or Bellows Assembly should be installed in the unit.

1363

Adjustrnent of Unit-The automatic mixture control unit must be properly adjusted before it is assembled to the carburetor. The most accurate and most satisfactory method is by setting the unit under the density equivalent to 'fhis procedure a certain standard altitude. placing in of the unit a chamber, which consists can be partially evacuated to the density for the corresponding standard altitude specified on the specification sheet, with a means of turning the adjusting screw on the mixture control unit so the flow of air past the mixture control needle in the unit will be restricted by the needle to such an extent that the water column ing this restriction rises to the point specified on the carburetor specification sheet. This equipment is shown in Figure 1334 while the procedure in making the adjustment is outlined below. 1. The Automatic Mixture Control Unit (3) as shown on Figure 1334 should be assembled on the Adjusting Stand (4) and the complete assembly should be placed in the Altitude Chamber (13). 2. The Hose Connections on the Adjusting Stand (4) should be fastened in place to the Air Exhaust Connection (8) and Air Intake Connection (9). 3. Push the Lock Nut Wrench (14) down over the Automatic Mixture Control Unit (3) so that it engagesthe Lock Nut (2). Likewise, push Adjusting Screw Wrench (15) down over the end of the adjusting Screw (1). 4. Connect the top of the 30" Single Leg Mercury Manometer (30) to the Altitude Chamber (13) wrth a %" Rubber Hose. 5. Now close the door of the Altitude Chamber (13) and apply vacuum to the chamber by adjusting Vacuum Valve (23) and Adjustable Bleeder (21) until the density in the Altitude Chamber (13), as ed on the Mercury Manometer (30), is equivalent to the altitude specified on the carburetor specification sheet. For instance, if the carburetor specification sheet specifies that the Automatic Mixture Control Unit is to be set at 20,000 feet standard altitude density, and the barometer reading at the moment is 29" and the temperature is 75o F., we refer to the 20,000 foot density curve on Figure 1336 and find that it intersects the 75" F. point at 16.4" of mercury absolute pressture. This 16.4" of mercury absolute pressure should then be subtracted from the 29" of mercury barometric pressure, to find that L2.6" of mercury vacuum is the reading on the Mercury Manometer (30) which will be equivalent to 16.4" of mercury absolute. 6. Air Valves (24), (I8), (26), and (27) shown on Figure 1334 should be closed and Air

1364

CARBURETORS Valve (25) should be turned so it is open only to the line running to the bottom of the 60" Single Leg Water Manometer (29).

7. Open the Air Pressure Valve (11) so that aii from the Shop Air Pressure Line 1fO; es through the Air Pressure Fl,educer Valve (12) into the Air Surge Tank (28) and up to the Air Adjusting Needle Valve (27). The Dial Pressure Gauge (22) wiU indicate the pressure of the air in the Surge Tank (28) as it is regulated by the Air Pressure Fleducer Valve (12). 8. Seethat a No. 5 Air Bleeder (16) is installed in the Air Adjusting Valve Block and a No. 15 Air Bleeder (17) is installed above the Air Valve (18). 9. Open the Air Adjusting Needle (27) gradually so that the water in the Water Manometer (29) is not blown out of the top of Now adjust the Air the manometer. Adjusting Needle Valve (27) and the Air PressureReducer Valve (12) until the water column in the Water Manometer (29) riseg to 42.4" with only the No. 5 Air Bleeder (16) open and so the water column drops to i4.7" when the Air Valve (18) is also open to a No. 15 Air Bleeder (17). This wil require a pressmreof approximately 10 lbe. pef square inch as ed on the Dial Pressure Gauge (22) and as adjwted by the Air Pressure Fleducer Valve (12). If when the No. 15 Air Bleeder is opened the value on the water column is higher than L4.7" the tank presrrure as ed on gauge (22) should be lowered slightly and the 42.4" value reset on the column, using needle valve (27). Then it should be rechecked with No. 15 bleeder (17) open to see that the drop is correct. If the initial reading was lowbr than 14.7" water, the pressure in the tank should be raised and ihe check repeated. 10. Now close the Air Valve (18) and open the Air Valve QQ w that air may flow from the Air Adjusting Valve Block through the Mixture Control Unit in the Altitude Chamber (13).

13. For instance, if the carburetor specification sheet states that the Mixture Control Unit is to be set at 30.8" water column reading, [which is the same restriction offered by a No. 42 metsrng jet installed in a fixture on the Adjusting Stand (4) in place of the Automatic Mixture Control (3)J, the Adjusting Screw Wrench U*t (15) should be turned until the Water Manometer (29) reads 30.8" then the Adjusting Screw Wrench (15) should be held while the Lock Nut Wrench (14) tightens the Lock Nut (2). Be careful that the Adjusting Screw (1) is not turned (It should be during this operation. noted that the No. 42 Jet restriction ig mentioned only for the purpose of comparing the repair station test equipment with that at the factory.) 14. Now close the Vacuum Valve (23), the Air Valve (24), the Air Pressure Valves (31) and (11), and nemove the Automatic Mixture Control Unit from the Altitude Chamber (13). The Automatic Mixture Control Unit should then be carefully lockwired and it will be ready for installation on the carburetor. Adtustment by Meoeurement Method-If the water manometer equipment is not available for setting these units, they may be set by measuring the distance from the bottom of the seat to the end of the needle with a depth micrometer. This method of setting units doe not take production tolerances of parts into consideration so should not be used except for emergencies. Extreme care should be used with this method as the needle is moved very easily when touched. The distance from the eni of the needle to the bottom of the seat at any specific barometric pressure and temperature may be found on the right hand margin of the curve sheet as specified on the carburetor specification sheet. This curve sheet will be similar to that shown in Figure 1337.

11. Open the Air Pressure Valve (31) to start Pneumatic Vibrator (20).

Erample lor Settlng-With the temperature at 80o F. and the barometric pressure at 29.3" Hg., the corresponding dimension on Figure 1421 isminus .053". This dimension should then be set on the unit by using the adjusting screw (1) Figure f$3.

12. Af,.ter checking the Mercury Manometer (30) to see that the Altitude Chamber is still evacuated to the correct figure, hold the Adjusting Screw (1) with the Adjusting Screw Wrench (15) and loosen the Lock Nut (2) with the Wrench (14), then holding the Lock Nut Wrench" (14) turn the Adjusting Screw Wrench (15) until the water column (29) rises to the point specified on the carburetor specification sheet.

Figure 1337 is used only as an example and should not be used in setting the units. The negative symbol indicates the needle is withdrawn into the bottom of the seat. If the dimension given is prefixed with a positive symbol, which is the case with dimensions comesponding to lower barometric pressures, this wiU indicat6 that the needle is to be extended out of the bottom of the seat. After the correct'setting is obtained, tighten the needle adjustment locknut (9) and safety wire, Figure 1333.

1365

CARBURETORS On earlier Automatic Mixture Control Units a seat bushing was pressedinto the needle bushing (15). The accompanying setting curve (Figure'1336) has the dimensions from the end of the needle to the bottom of the seat listed for the later units. Therefore, when setting a unit of the early design minus .031" should be added to the dimensions listed. For instance, if an old unit having the presred-in seat bushing were to be set by the measurement method, the dimension, say minus .080" found in the right hand column should have minus .031" added to it. The resulting dimension would, of course, be minus.111". units bear assembly numIdentlffeatlon-All bers and serial numbers for identification purposes. Every different assembly containing parts with different part numbers such as needles, screens, housings, or bushings carries a separate assembly number. No unit should be used on a carburetor except one that conforms to the number listed on the carburetor specification sheet.

Assembly Number \-

A-17606 A-17636 A-r77L6 A-r7726 4-30041 A-30063 4-30117 A-r7697

The needles used in these units are identified by a letter. The early needles had this letter stamped on the head but on the later needles the letter has been put on the tapered portion of the needle with an electric pencil so it may be read when assembled in a unit. A different letter as well as a different part number is assigned to each needle having a different contour. The serial number which is stamped on the Bushing (15) shown on Figure t33'3 , following the Unit Assembly number should in every case agree with the serial number stamped on the bellows assembly. Therefore, if a new bellows is installed in the Unit the stamping on the Bushing should be changed to agree with the number stamped on the bellows. Similarly, if any parts of the Unit are changed to make it conform to a different assembly number, the new assembly number should be stamped on the Bushing (15) in place of the old number. Below is a chart listing some of the Units and their needles. See their assembly drawings for other differences and information:

Needle Number P-22753 P-60264 P-60996 P-60996 P-61219

Needle Letter E F

P-61219 P-61219 P-60909

Needle Contour 40" 9' and,4"29' ALo

and 5o

c

41o

and 6o 30'

C G

4L"

and 6o 30'

4I"

and 7o and 4o

G G D

4Lo

and 7o and 4o

4lo

and 7o and 4o

41"

and 7o 30'

COMPLETE INFORMATIONON THIS TEST EQUIPMENT WILL B E FURNISHEDON REQUEST

ALTITUDE CHAMBER WREI.ICH TING SCREW WREN|CH

Oea.rcrrnrc scRE

VACUUM LINE

@roc

PNEIA4ATIC VIBRATOR

@n-,rorraarc Mrxr coNTRoL

AD.JUSTABLE BLEEDER

@ao..usrrr.rc DIAL PRESS.JREGAUGE

oee DaL@ar,aes -GAUGE I-25O45

@'localNo

STAND FOR TRA/EL CHECKING OF AUTO MIXT CONT NEEDLE

Cauro -CONT urxr

UNIT AIR EXHAUST CONNECTION

AIR BLEEDE AIR BLEEDE

VALVE VALVE

@nrn TNTAKE @NNECTION

@arn PREssuRE

vALVE @nrn PRESSURE REDucER @arn PRESsuRE

@nrn sr

TESTINGAND SETTNG AUTOMA Fig.

,36;

1

I l

------@oo'

srxrcle LEG wATER MANoMETER

AO,SIruCUE LEG MERCURYMANOMETER

AIR PRESSUREVALVE FOR VIBRATG

.$ara vALVE vALVE $are

@arn

i$g1ti

ADJJsTNG NEEDLE

@arn suRGErANK

rNG AUTOIUATICMIXTURE CONTROL UNITS Fig. 1334

1369

375 50

32s

oo 275 250 225 200 75

.r50 t25

oo 75

o50 .o25

.o

Fis. 1335

CURVESOF CONSTAI{TA I R D E N S I T Y F O R S T A N D A R DA L T I T U D E S

G

ra 0

G lr, l!

o 5o lr, a o ?=

I

rH I

:2 - g

G

o' ul

F I

t-r o o, o 7 <

A I R T E ] I P E R A T U R E -D E G R E E S F A H R Fig. 1336

T Y P I C A L C U R V E F O R S E T T I N GA U T O M A T I CM I X T U R E

c

1371

lo

o

2 9 2 8 2 7 2 0 2 t 2 a BAROTETRIRESSURE Fig. 1B3Z

Overview 26281t

More details 6y5l6z

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