TM-9-2815-220-34 Direct Support Manual for AVDS-1790-2C and AVDS-1790-2D Engines Download
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mediate compression rings with the marking "TOP" or "PlP" mark toward the piston dome. Oil control rings nre symmetrical and may be installed with either side up. Install all rings using remover and re pincer Part No. 7950177 s shown in figure 3-181. Use care in install i ng rings to avoid damag- ing ring lands or distorting r ings . TM 9-2815-220-34 b. Install piston pin in bore of piston. The piston pin retaining rings should not be installed until the piston and cylinder are installed on the engine, paragraph 3-164. 3-68. General Section IX. REPAIR OF CYLINDER ASSEMBLY WARNING This section covers the repair of the cylinder as- sembly. Specific instructions on disassembly, cleaning, inspection, repair and assembly accom- pany the repair operations. Repair standards of individual components follow the inspection pro- cedures. Stud identification information is in- cluded in the repair procedures. 3-69. Disassembly a. Cylinde1·. NOTE The twelve rocker arm cover assemblies a1·e machined with cylinder assemblies as matched units. The covers are stamped with matching letters and numbers (fig. 3-64) to correspond with the letter and number stamped on the cylinder. Keep covers with their respective cylinders. (1) Place cylinder with valves, springs, and re- tainers on removing and inserting valve stand (fig. 3-186). (2) Secure valve lifter assembly Part No. _ 8761535 (fig. 3-186) lo the cylinder head with four cover bolt.s and Oat. washers. The valves and locks are under heavy spring tension. Exercise extreme care when removing locks, retainers and springs. (3) Compress exhaust valve spring and upper retainer. Remove two valve locks (fig. 3-187), from the groove in valve stem. Tap valve spring retain- ers to free locks. Carefully loosen lifter screw to release valve springs. Remove valve lifter assembly. (4) Remove intake valve spring upper retainer. (5) Remove exhaust valve inner, intermediate, and outer valve springs, upper retainer and exhaust valve rotor (fig. 3-188), from valve stem. Remove intake valve springs, retainer, and seat in the same manner. (6) Remove the cylinder from removing and inserting valve stand (fig. 3-188) making certain valves do not drop out. Replace cylinder on side and remove the intake and exhaust valves through the cylinder bore. NOTE Temporarily install valve rocker arm cov, ers on cylinders with two bolts to prevent damage and mismatching of parts. Refer to figure 3-64 for cover and cylinder iden- tification. Change 3 3·96 .3