ASSEMBLY OF ENGINE

7. Valves, Seats and Guides

b. With a micrometer, check journal for out of

round. Correct crankpin size is 1.186. If out of

a. Check clearance of old valve stems in guides.

round, replace shaft or regrind to .010

b. If worn, replace valve guides. To remove,

undersize.

guides, we recommend that they be driven

c. Check gear, keyway and tapered part of shaft

down into the valve chamber and carefully

for wear. If worn, replace shaft.

broken, taking care to not damage cylinder

block. It will be necessary to ream guides to

4. Connecting Rod

gain correct fit.

a. Check rod for wear, score marks, running

clearances, and side clearance. Replace rod if

c. Consult Parts Identification Section for correct

worn beyond high limit of clearances shown in

valve number.

Some applications require

table on page 23.

special valves.

b. Connecting rod bearings are an integral part of

d. Intake valve seat is normally machined into

the rod and not separately replaceable.

block. Separate inserts are sometimes used.

c. Connecting rods .010 undersize are available

e. The exhaust valve seat is a moly-nickel chrome

for reground crankshafts.

or Stellite insert.

5. Piston

f. The seating surfaces should be held as nearly

as possible to 1/32" in width. Seats with more

a. If cylinder block does not require reboring and

than 1/16" seating surface should be

old piston is free of score and scuff marks,

reconditioned with 45° and 15° cutters and

check piston ring grooves and lands.

ground to form proper seat.

b. Clean grooves and fit NEW rings.

c. With rings in place, check clearance with a

ASSEMBLY OF ENGINE

feeler gauge. Replace piston if a .005 feeler

can be inserted between ring and land.

1. Install rear main bearing by pressing it into cylinder

block with shielded side facing to inside of block. Figure

d. When inserted in cylinder, piston ring end

15.

clearance should be between .007 and .017.

e. Never re-use old rings.

2. Governor Shots

6. Piston Pins

a. Current production engines have a cross shaft

with an extension riveted in place to line up with

a. Very little wear takes place on piston pin or in

governor gear. Figure 16. A needle bearing is

piston bosses.

provided (in block) to hold cross shaft in

b. Assemble piston to connecting rod. Use a

alignment.

commercial rod aligner. Piston must be square

b. Engines manufactured before serial No.

with cylinder bore and crankshaft.

202305 have a short-angle arm and use bushing

nut for a bearing and for shaft alignment.

Figure 17.

3. To Install Governor

a. Place cylinder block on its side. Slide governor

shaft into place from inside of block.

b. Place speed control disc on governor bushing

nut and thread bushing nut into block, clamping

throttle bracket into place.

c. The governor shaft can be adjusted for end

clearance by moving needle bearing in block.

Set bearing to allow a slight back-and-forth

movement of the shaft.

d. Before serial 202305, a lock ring is used to hold

governor shaft in place.

Figure 15

Installing Rear Main Bearing