1 Connecting rod assy (6)
7 Bearing (6)
should be 0.0035-to 0.005-inch on first ring, 0.0035- to
2 Cotter pin (12)
8 Ring set (6)
0.0055-inch on the second and third rings, and 0.003- to
3 Nut (12)
9 Piston and pin assy
0.0045-inch on the fourth. If rings do not meet these
4 Capscrew (12)
10 Retainer (6)
specifications, replace them.
5 Connecting rod and cap (6)
11 Pin (6)
(6) Check piston-to-cylinder clearance. Select two
6 Bearing sleeve set (6)
12 Piston (6)
strips of feeler stock 10 inches long, /2-inch wide, and
0.002 inch thick. Attach feeler stock to a spring scale.
b. Cleaning, Inspection and Repair.
Invert piston and place feeler stock and piston in the
cylinder. Withdraw feeler stock, observe scale reading.
(1) Clean all parts.
The required spring scale readings is from 5-to 10-
(2) Inspect all parts for cracks or other defects
pounds. Test in several places. Replace piston that
Replace defective parts.
does not meet requirements.
(3) Check fit of piston pin the boss of piston and in
piston pin bushing. The piston pin should 0.8591-to
0.8593-inch in diameter with an out-,of round and taper
allowance of only 0.0003 inch. The proper piston pin fit
in piston pin bushing with a 0.0004 inch clearance. The
thin film of lubricating oil.
piston pin 0.0001 inch larger than piston pin boss a
requires a force fit.
(4) Check piston ring gap by installing a piston, ring
rings, piston, connecting rods, sleeves, and bearing.
in cylinder. Position a piston in the cylinder and push it
(2) Check clearance between sleeve bearing and
against the ring until the ring is square with cylinder
crankshaft. Place a plastic gage between bearing and
walls. Gap should measure 0.007-0.017-inch. If gap
connecting rod journal on crankshaft. Torque, nuts 35-
exceeds 0.017 inch, replace ring If gap is less than
to 40-foot pounds. The required clearance is 0.0015
0.007 inch, file end with a flat file until proper gap is
inch. Replace bearing set if necessary to obtain
(5) Check piston ring groove clearance. Install; a
piston ring on piston and measure with a feeler gage
(4) Install cylinder head (TM 10-3950-203-20).
between ring and piston land. Clearance
Section V. CRANKSHAFT AND CAMSHAFT
5-9.Cranshaft, Bearings and Seals
(4) Remove the crankshaft, bearings and seals as