TM 9-4940-549-14&P
(12) Remove minor nicks and burrs from piston by polishing with
crocus cloth. Clean to remove abrasive residue.
(13) If necessary, replace both piston pin and bushing.
NOTE
If new piston pin and bushing are
used, check connecting rod alignment
on a standard aligning fixture.
(14) Inspect piston for deep scores and scratches and other damage.
(15) Insert each piston into
its cylinder bore with a piece of 1/2 x
0.0050 feeler ribbon.
A force of 5 to 8 pounds should be re-
ribbon. Replace all pistons if any are
quired to remove each
not within the required
limits.
NOTE
Cylinder bores may be rebored to ac-
cept oversized pistons.
(16) Fit each piston ring into place in its cylinder bore and using a
feeler gauge, measure gap dimension. Gap shall be 0.0100 to
0.0200 inch. If gap is under 0.0100 inch, file as follows:
(a) Hold a file in a vise.
(b) Grasp piston ring in both hands.
(c) Insert file into ring gap and move ring down the entire
length of the file. Be sure to apply equal pressure on the
ring.
(17) Roll each ring all the way around its piston groove to check
If clearance is insufficient, lap the sides of the ring
clearance.
on a piece of No. 000 grit emery cloth laid on the flat surface.
d.
Assembly.
(1) Using a piston ring expander install oil control ring (15, figure
onto pistons (24).
NOTE
If replacement piston rings have dots
on the rings, the rings should be in-
stalled with the dots toward the pis-
ton head.
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