TM-9-2815-237-34 HMMWV Engine Direct Support & General Support Maintenance Manual Download
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TM 9-2815-237-34 2-54 Change 1 2-18. CONNECTING ROD AND PISTON REPAIR This task covers: a. Disassembly c. Inspection b. Cleaning d. Assembly Manual References TM 9-2815-237-34P Equipment Condition Engine disassembled into subassemblies (para. 2-15). a. Disassembly 1. Remove top compression ring (1), second compression ring (2), and oil ring (3) from piston (4). Discard rings (1), (2), and (3). 2. Remove two snaprings (5), piston pin (15), and connecting rod (13) from piston (4). Discard snaprings (5). 3. Remove two nuts (11) and rod cap (12) from connecting rod (13). 4. Repeat steps 1 through 3 for remaining pistons and connecting rods. b. Cleaning Clean all components in accordance with para. 2-9. c. Inspection NOTE • For general inspection instructions, refer to para. 2-10. • To identify correct piston size for standard, Hi-Limit, and oversize pistons, check code stamped on face of piston, and determine correct piston size. Refer to para. 2-45, table 2-4, for piston-cylinder specifications. • 6.5L engines do not have Hi-Limit pistons. 1. Inspect piston (4) for cracks at ring lands (6), skirt (7), and pin bosses (16). Replace piston (4) if cracked. 2. Inspect piston (4) for scoring, galling, and scuffing. Replace if scored, galled, or scuffed. 3. Measure piston (4) at center (8) and bottom (9) of piston skirt (7) using micrometer. If measurement at bottom (9) is smaller than measurement at center (8), piston skirt (7) is collapsed and piston (4) must be replaced. 4. Inspect connecting rod (13) and rod cap (12) for distortion or damage. Replace connecting rod (13) if either are damaged or distorted. INITIAL SETUP: Tools General mechanic’s tool kit: automotive (Appendix E, Item 1) Feeler gauge (Appendix E, Item 13) Micrometer (Appendix E, Item 16) Piston ring expander (Appendix E, Item 20) Materials/Parts Sixteen snaprings (Appendix D, Item 49) Eight piston ring sets (Appendix D, Item 37 or 48) Lubricating oil OE/HDO (Appendix B, Item 13)