TM-9-2815-202-34 Technical Manual for 8V71T Engines for M109 Howitzer Download
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TM 9-2815-202-34 (4) Check used liner for taper and out of round. Liner taper is difference between O.D. at 0.625 and 9.875 inches positions. Taper must not exceed 0.002 inch and out of round must not exceed 0.0025 inch. If out of round exceeds 0.0025 inch, rotate liner 90 degrees in block bore and recheck. NOTE Liners, standard and oversize, have an inside diameter of 4.2489 to 4.2511 inches. Liners are available in 0.005, 0.010, 0.020, 0.030 inch oversize on outside diameter. (5) When an oversize liner is installed, stamp amount of oversize on top of cylinder block bore adjacent to liner counterbore. e. Honing CAUTION Do not modify surface finish of new liner. Liner is properly finished at factory so changes will adversely affect piston ring seating. NOTE Used cylinder liners must be honed to break glaze resulting from extended operation and to remove ridge formed at top of piston ring travel. If glaze is not removed, time required to seat new piston rings will be lengthened. A scrap cylinder block makes an excellent honing fixture. (1) Place liner in fixture (6). CAUTION If liner is honed in block, completely dismantle engine to insure all abrasive material is cleaned out. (2) A hone (7) equipped with 120 grit stones should be worked up and down full length of liner a few times to produce a crisscross pattern of hone marks on 45 degree axis. WARNING Compressed air used for cleaning purposes will not exceed 30 psi. Use only with effective chip guarding and personal protective equipment (goggles/shield, gloves, etc). (3) Remove liner from fixture and clean thoroughly. Dry with compressed air and check surface for burrs. 4-147