TM-9-2815-202-34 Technical Manual for 8V71T Engines for M109 Howitzer Download
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TM9-2815-202-34 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 retainer. (2) Installation - Piston Rings NOTE Before installing piston rings, assemble piston and rod as directed in previous section. (a) Lubricate piston rings and piston ● ● with engine oil before installing rings. CAUTION 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 oil consumption. NOTE 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. WARNING Do not grasp or graze sharp edges of oil control rings with bare hands. Rings are extremely sharp and can cut personnel when mishandled. ● ● 6-38 NOTE 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.