TM 5-4310-350-14
valves be sure to seat larger diameter of the
(6) Disassemble cylinder block from crank-
spring in th cage of all valves.
case as shown in figure 5-6.
(7) Disassemble connecting rods, pistons
5-6. Crankcase
and rings as shown in figure 5-8.
a. Removal and Disassembly.
NOTE
(1) Refer to figure 5-8 and remove the
unloader assembly.
Mark connecting rod and piston to assure correct
relationship at reassembly.
(2) Remove the hand hole plate and fly-
wheel.
NOTE
(3) Remove bearing caps (fig. 5-8) and
Do not remove the connecting rod bushings unless
push connecting rods and pistons up to the top
inspection reveal them defective.
of the cylinder bore. Remove the capscrews that
secure unloader housing to crankcase.
b. Cleaning, Inspection and Repair.
(4) Drive the crankshaft, bearings, and
(1) Clean all parts with an approved clean-
unloader housing from the crankcase.
ing solvent and dry thoroughly.
(2) Inspect the cylinder block for broken
CAUTION
cooling fins and cracks. Inspect the cylinder bore
Before driving the crankshaft from the
for wear, scoring, pitting or other damage.
crankcase, he sure the connecting rod
Replace the block if defective.
journals are in an upright position.
(3) Measure the clearance of the piston pin
(5) Using suitable puller r e m o v e the
to the piston pin bushing. Check for proper fit.
unloader housing and bearing from the shaft.
Aline or replace connecting rods, if necessary.
(6) Remove the oil seal from the crankcase.
(4) Place the piston rings in the cylinder
bore with the piston ring square in the cylinder
NOTE
bore about (0.500) inch from the top.
Do not remove the oil level gage from the crank-
(5) If the ring gap is less than the specified
case unless the gage is leaking or defective.
width, file across but ends of the rings to increase
b. Cleaning, Inspection and Repair.
the gap to the required tolerance. If the ring gap
(1) Clean all parts in an approved cleaning
is greater than required, replace the entire set of
solvent and dry thoroughly.
rings.
(2) Inspect the crankcase for cracks, scores,
(6) Measure the ring groove in the piston
and distortion. Measure the crankcase journals
for wear. Replace piston if necessary.
for wear. If the connecting rod journals measure
c. Reassembly and Installation.
0.0005 inch (0.0013 cm) out-of-round, replace
(1) Refer to figures 5-6, 5-6.1, 5-7 and 5-8 and
the crankshaft.
reassemble and install the pistons, piston rings, con-
(3) Inspect the crankshaft bearings for
necting rods and cylinder block taking the follow-
rough, pitted, or scored rollers. Replace a defec-
ing precautions:
tive bearing.
(a) If new connecting rod bushings are to
(4) Inspect the crankcase for cracks, breaks
be installed, and are not prefit, ream the bushings.
or other defects. R e p l a c e the crankcase if
(b) When installing piston rings expand
defective.
them carefully and sufficiently to allow the ring
c. Reassembly and Installation.
to slide freely over the piston to the position.
Starting with the bottom ring, install piston rings
assemble and install crankshaft in crankcase using
in their proper grooves. Stagger ring gaps so
the following procedures:
that they are not lined up.
(a) Always install new oil seal in crank-
(c) Lubricate each piston and connecting
case.
rod assembly with a light coat engine oil before
(b) Press bearing cup in the unloader
installing in cylinder block. Compress the piston
housing.
rings carefully when installing in cylinder.
(c) Install new gasket on the unloader
(d) When installing cylinder block to
housing.
crankcase always use new flange gasket and
5 - 7 . Electric Motor
torque nuts to 45 ft.-lbs. torque.
a. Removal and Disassembly.
(e) Torque connecting rods nuts to 25
ft.-lbs. torque.
(1) Refer to paragraph 4-11 and remove the
electric motor.
Change 2
