TM-9-2815-205-24 Technical Manual for M113 Engine 6V53 6V53T Download
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INSPECTION-ACCEPTANCE AND REJECTION CRITERIA NOTE Trunk piston can come in two configurations as shown. The new configuration has eight or sixteen oil drain holes and J-relief. The old configuration has eight oil drain holes and no J-relief. Either configuration is acceptable and matching throughout an engine is not required. 1. For piston, check cylinder liner and block bore for excessive out of round, taper, or high spots, which could cause failure of piston (WP 0097). NOTE Overheating or burned spots on piston may indicate an obstruction in connecting rod oil passage. 2. Examine piston for score marks, cracks, damaged ring grooves, loss of tin plating, or indications of overheating. Using a crocus cloth, remove light score marks from piston. Replace any piston severely scored or overheated. Discard piston if cracks are found across internal struts. PISTON SUITABLE FOR INSTALLATION. PISTON SLIGHTLY SCORED. USE ONLY AFTER REMOVING SCORE MARKS BY POLISHING WITH CROCUS CLOTH OR HARD INDIA STONE. PISTON BADLY SCORED- UNFIT FOR USE. MAINT_356 Figure 4. Piston Inspection. CAUTION Do not polish or refinish piston pin. Hand polishing or refinishing will destroy precision finish and result in rapid bushing wear. 3. For piston pin, inspect for signs of fretting. Discard piston pin if fretting is present. 4. Measure piston pin diameter. Diameter of new piston pin is 1.3746–1.3750 inches (34.915–34.925 mm). TM 9-2815-205-24 0094 0094-6