Disassembling Engine For Complete Overhaul

Disassembling O.H.V. Engine

(After Removing From Chassis Completely Assembled)

1. Remove upper-end parts as outlined under "Disassembling Engine for Top Overhaul Only" (O.H.V. Engine)

2. Remove pistons. See "Piston and Pin,"

3. Remove generator as outlined under "Removing Generator,"

4. Remove circuit breaker assembly from crank-case: Free low tension wire from clip on crank-case—if wire is shielded, disconnect metallic shielding from crankcase stud. Remove relay and relay bracket. Remove two cap screws (9)

and then circuit breaker completely assembled can be lifted off. Be careful not to damage base gasket if new one is not available.

5. Remove gear case cover: Remove gear case cover screws and cover is then free to be removed. Cover is located on dowel pins which fit rather snugly and it must be worked off these pins carefully to avoid damage to cover and joint faces. Do not pry off with screwdriver inserted between joint faces. Use a hammer and a block of wood and tap lightly at the ends where the cover projects beyond the gear case.

Unless a new gasket is available, be very careful not to damage or break the old one as this gasket is special as concerns thickness and hole for oil passage. It should be replaced with a "factory-made" gasket.

6. Remove timing gears: After removing lock rings and collars from gear studs, gears, breather valve and pinion shaft fittings, except gear shaft bearing oil seal ring can be removed. Gear shaft bearing oil seal ring cannot be removed until after removal of oil pump drive gear.

7. Remove oil pump:

remove in order named, the five nuts, one cap screw and washers that secure pump to crank-case, pump cover, governor rotor, cover plate and the countersunk flat head screw that secures pump to crankcase.

Remove lock ring, and drive shaft gear and key from inner end (inside gear case) of pump drive shaft, and then pump with shaft assembled can be removed from crankcase.

Unless new gaskets are available, be very careful not to damage or break the old ones. These are special gaskets as concerns both thickness and holes for oil passages. It is not advisable to attempt to replace them with "home-made" gaskets. Leaving out one hole or getting one in the wrong location is enough to put the entire oiling system out of commission. When new gaskets are needed, they should be replaced with "factory-made" gaskets.

8. Disassemble crankcases: Crankcases are held together with one cap screw, six studs with a nut on each end and one crankcase breather stud assembly. The cap screw enters through left case and threads into right case. Take out cap screw and remo\ _> nut from one end of each stud. Three of these studs, the one at top between cylinders and two at bottom are a tight fit and will have to be driven out with a drift of somewhat smaller diameter than studs. With all studs and screws removed, crankcases can be separated. If they don't come apart freely, tap at mounting lugs, using a block of wood and a hammer. Main bearing parts shown in Illus. 62 are now exposed.

9. Disassemble flywheels: Remove lock washer and nut from left end of crank pin. Tilt flywheel assembly on right flywheel and strike rim of left wheel with soft hammer about 90° away from pin. One or two sharp blows will usually loosen wheel. Do not strike wheel on its side, as doing so might either break flywheel or damage the tapered hole. With flywheels apart, connecting rods and roller bearing assembly can be removed from crank pin. Note that female (forked) rod is for the rear cylinder and male (single end) rod is for the front cylinder.

In connection with a complete overhaul, where all main bearings as well as connecting rod lower bearings cure to be refitted, remove all shafts from flywheels. When crank pin is removed from right flywheel, it will be noted that this end of pin is a taper fit in flywheel, the same as the other end, but in addition is keyed. The purpose of this key is to locate the drilled oil passage in crank pin so that when wheels are assembled it will register exactly with drilled oil passage in right flywheel.

Installing Timing Gears (O.H.V. Engine)

Before installing timing gears, install on pinion gear shaft in the following order: oil pump drive gear (34), spacing collar (35), spring (36) and pinion gear (37) as shown in Illus. 62.

Install the .050" thick steel thrust washer on inner end of cam gear shaft. Install timing gears (2) and (4) and breather valve (3) in gear case with marks in alignment, including the two marks on pinion gear, as shown in Illus. 64. Install spacer and split lock ring on circuit breaker drive gear stud. Install breather screen and screen separator in breather pocket in crankcase, with separator above as shown in Illus. 64, and scalloped edge of separator inward against crankcase.

.005" endplay. Check endplay of cam gear with a thickness gauge, through tappet guide hole.

After correct endplay has been established, install tappets and tappet guides. See "Valve Tappets and Valve Tappet Guides,"

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