and caps connect the connecting rods to the crankshaft.
b. Removal.
(1) Remove the canopy (para. 68).
(2) Remove the manifolds (para. 106).
(3) Remove the carburetor (para. 106).
(4) Remove the cylinder head shrouding (para. 68).
(5) Remove the cylinder heads (para.107b).
(6) Remove the engine and water pump assembly (para. 121).
(7) Remove the oil pan and oil pump assembly (para. 133).
(8) Remove the locknuts (6, fig. 40), nut (5), connecting rod cap (4), lower bearing half (3), and upper
bearing half (3) from the connecting rod (2) and crankshaft (1).
c. Disassembly.
(1) Push the piston (7) and connecting rod (2) out through the top of the cylinder bore.
(2) Lift the connecting rod bolts (11) out of the connecting rod (2).
(3) Remove the compression rings (12),scraper ring (13), and oil ring (14)from the piston (7) with a
suitable ring expander.
(4) Remove the retaining rings (9) from the piston (7).
(5) Remove the piston pin (8) and the connecting rod (2) from the piston (7).
(6) Place the connecting rod (2) in a press and press out the bushing (10).
d. Cleaning.
(1) Clean all parts in an approved cleaning solvent and dry thoroughly with compressed air.
(2) Clean the carbon from the piston top and from the ring grooves.
e. Inspection and Repair.
(1) Inspect the piston pin bushing for wear or out-of-round. The proper clearance between the piston
and bushing should be from 0.005 to 0.001 of an inch. When replacing a bushing and pin, ream
the bushing to a light press fit on the pin. When pressing in new bushings, be careful to align the
oil hole in the bushing and oil hole in the connecting rod.
(2) Inspect the connecting rod for breaks. Straighten bent or twisted rods. Make sure the oil holes in
the connecting rods are open.
(3) Inspect the bearing halves for wear or scoring. Replace both bearing halves if either one is
unserviceable. Measure the bearing-to-crankshaft clearance by installing a piece of 0.001 of an
inch shim stock on both bearing halves. Assemble the connecting rod and cap with shimmed
bearings to the appropriate crankshaft journal, and tighten the nuts to 14 to 18 foot-pounds torque.
A slight drag on the shaft, when turned by hand, indicates proper bearing clearance.
(4) To measure the piston ring gap, place the ring into the cylinder bore in the approximate operating
position and measure the gap with a feeler gage. The correct gap is 0.015 of an inch. If the ring
gap exceeds 0.030 of an inch replace the ring.
(5) Measure the piston ring side clearance. Replace the piston when clearance exceeds 0.006 of an
inch in the top and bottom grooves, or 0.005 of an inch in the intermediate groove. The top ring
should be from 0.002 of an inch to 0.0035 of an inch. The scraper ring is from 0.001 to 0.0025 of
an inch and the oil ring is from 0.0025 of an inch to 0.005 of an inch.
(6) Measure the piston pin fit in the piston. If new pistons are being used, ream the piston pin bores in
the piston to a clearance not exceeding 0.005 of an inch.
f. Reassembly.
(1) Press the bushing (10) into the connecting rod (2).
Note. A number (
) is stamped on the side of the rod and cap to match each
connecting rod with its corresponding cap. The SC numbers must be on the same side of all caps
and connecting rods. An arrow located on the top of the piston will be placed facing the direction
of the engine rotation. The piston and connecting rod will be installed in the same bore from
which it was removed. The number located on the connecting rod will indicate its location in the
engine.
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