b. Check the side clearance of the connecting
rod (the piston pin end) to the piston boss with a feeler
guage. Clearance will be 0.040/0.050 inch.
pistons in hot water
c. Lubricate piston and rings with clean
before removal of
lubrication oil and install chrome compression ring in top
piston pins. This will
piston groove. All rings must be installed with the word
permit pin to be
"Top" toward the top of the piston. Stagger ring gaps so
pushed out easily
they are not in line with each other or with piston pin.
d. Install connecting rod and piston assembly
matching cylinder and numbers stamped on connecting
4-72. Cleaning, Inspection and Repair
rod. Locate number on connecting rod toward camshaft
a. Clean all parts with an approved cleaning
side of engine. Install connecting rod bearing cap so
solvent and dry thoroughly.
numbered side of cap is matched with numbered side of
b. Check connecting rods, caps, and U-bolts by
Lubricate U-bolts, nuts, and lock plates and
magnetic inspection, for cracks. If cracks are detected,
replace rod and cap as an assembly.
e. Tighten front U-bolt nuts, then rear U-bolts
c. Check connecting rod piston pin bushing
nuts to 15.'20 foot pounds. Then tighten each nut to 30
diameter to see that it is within tolerance limits (table 1-
foot pounds in same sequence.
Loosen all nuts completely to remove tension,
d. Check connecting rod alignment. (Refer to
then repeat step (d) above.
table 1-1 for tolerance and wear limits). Replace
g. Advance each nut one-half hex (30'-). Finish
tightening by advancing additional half hex (300).
e. Check the pistons for piston ring groove
h. Check torque in clockwise direction. If less
clearance. Hold new ring flush with piston land and
than 38 foot-pounds is required to break nut loose after
insert 0.006 inch feeler gage. If gage enters groove,
tightening sequence is completed, remove U-bolts and
wear is excessive and piston must be replaced.
replace with new U-bolts.
Check piston ring gap by inserting each
Check side clearance between connecting
compression ring in mating cylinder liner, seating it
rod and crankshaft on both sides of connecting rod by
squarely with a piston head in an unworn surface of liner.
tapping rod from side to side with rubber mallet and
g. Measure ring gap with feeler gage. (Refer to
must not be less than 0.008 inch.
h. If necessary file ends of the rings to obtain
the minimum ring gap.
Never file chrome
plated piston rings.
at right angles to piston pin bore. (Refer to table 1-1 for
allowable wear limits and tolerances).
Check piston pin bore and piston outside
diameter. (Refer to table 1-1 for allowance tolerances).
k. Replace all damaged or defective parts as
necessary. Always replace connecting rod bearings at
4-73. Reassembly and Installation
rod and piston assemblies as shown.
water before installing
the piston pins to
Figure 4-25. Checking rod to crankshaft clearance.