6-34. PISTON AND CONNECTING ROD MAIN
TENANCE (TRUNK TYPE) (Cont)
(f) Check each piston pin retainer for
proper sealing with leak detector
(15). Place suction cup over
retainer and hand operate lever
to pull a vacuum of ten inches of
mercury on gage. A drop in gage
reading indicates air leakage at
(2) Installation - Piston Rings
Before installing piston rings,
assemble piston and rod as directed
in previous section.
(a) Lubricate piston rings and piston
with engine oil before installing
Do not overlap ends of oil control ring expanders. An overlapped expander will
cause oil control ring to protrude beyond allowable limits and result in breakage
when inserting piston in ring compressor.
Do not cut or grind ends of expanders to prevent overlapping. Cutting or grinding
ends will decrease expanding force on oil control rings and result in high-lubricating
Scraper edges of all oil control rings must face downward (toward bottom of piston) for
proper oil control.
(b) Install two ring expanders (16) in oil control ring grooves in piston (10). Install oil ring
expanders with legs of free ends toward top of piston.
Do not grasp or graze sharp edges of oil control rings with bare hands.
Rings are extremely sharp and can cut personnel when mishandled.
Upper oil control ring groove requires a one-piece
two-piece ring (upper and lower halves).
Install upper and lower oil control rings by hand.
ring, and lower groove requires a
Scraper edges of all oil control rings must face downward (toward bottom of piston)
for proper oil control.