TM-9-2815-202-34 Technical Manual for 8V71T Engines for M109 Howitzer Download
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TM 9-2815-202-34 4-33. PISTON AND CONNECTING ROD MAINTENANCE (CROSS-HEAD) (Cont) f. Fitting Piston Rings (1) Insert top piston ring inside cylinder liner in normal area of ring travel. Use a piston skirt to push ring down to insure ring is parallel with top of liner. Measure ring gap with feeler gage. Refer to Table 4-3 for ring gap specifications. Repeat procedure for balance of compression CAUTION File or stone both ends of compression ring from outer surface to inner surface to prevent chipping or peeling of chrome plating on ring. Ends of ring must remain square, and chamfer on outer edge must be approximately 0.015 inch. TABLE 4-3 PISTON RING SPECIFICATIONS GAP (NO.2, AND 3) CLEARANCE RING TO GROOVE: TOP RING NO.2 NO03 OIL CONTROL RINGS GAP (TWO RINGS IN LOWER GROOVE) GAP (ONE RING IN UPPER GROOVE) CLEARANCE (TWO RINGS IN LOWER GROOVE) CLEARANCE (ONE RING IN UPPER GROOVE) MINIMUM MAXIMUM .0230 IN (.0286CM .0380 IN. (.0965CM) .0180 IN. (.0457CM) .0430 IN. (.1092CM) .C080 IN. (.0025CM) .0050 IN (.0127CM) ,0100 IN. (.0254CM) .0130 IN (.0330CM) .0040 IN. (.0101CM) .0070 IN. (.0177 CM) .0080 IN (.0203CM) I .0230 IN. (.0584CM) .0050 IN. (.0127CM) .0140 IN. (.0356CM) .)015 IN. (.0038CM) .0055 IN. (0139CM) .0010 IN. (.0025CM) .0040 IN (.0101CM) (3) Using feeler gage, measure ring side clearance by inserting edge of ring in appropriate groove of piston. Refer to Table 4-3 for ring side clearance specifications. g. Assembly (1) Piston and Rod Assembly (a) Install pin bushing (17) in piston dome (15). It should slide into piston dome without force. NOTE Soak seal rings in engine oil for 15 minutes prior to installation on dome. (b) Lubricate seal ring (16) and install in groove on piston dome (15). Change 1 4-138