TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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Note. Before removing cylinder assemblies, it will be necessary to check the breaking torque of the 14 nuts attaching each cylinder assembly to crankcase assembly. This check is necessary to determine whether base nut stud has stretched. All stretched studs must be replaced. 1. Check breaking torque of the 14 nuts (B) securing cylinder assembly to crankcase assembly using box wrench (A)-5120-678-5287 in combination with torque wrench. When torque required to break a nut loose is less than 600 pound inches, remove nut, apply antiseize compound FSN 9150-663-1770 to stud, install nut and tighten to a torque of 600 to 660 pound inches. When nut does not tighten to the recommended torque, stud is stretching and must be replaced, Mark stud for replacement. Refer to paragraph 6-4e for instructions on replacement of studs. 2. After checking the breaking torque, remove all nuts (B) except one on each side of cylinder. The remaining two nuts are removed after piston has been positioned to top dead center for removal (fig. 5-144). Figure 5-143. Checking breaking torque of cylinder base nuts, using box wrench-5120-678-5287. Note. Before removing each cylinder assembly, the crankshaft must be turned to position the piston of the cylinder being removed to top dead renter. Rotate crankshaft using splined wrench -5120-793-7895 (fig. 5-91) and observe when (connecting rod has raised piston to top dead center. Make certain each piston is properly positioned before attempting cylinder removal. 1. With right bank cylinder assemblies in a vertical (upright) position remove the remaining two nuts (A) from each right cylinder assembly. Make certain each piston is positioned at top dead center before at- tempting removal. 2. Do not remove the nuts (B) holding the left cylinder assemblies to crankcase until left cylinders have been rotated to an upright position for removal. Figure 5-144. Right bank cylinders in vertical position for removing or installing cylinders from crankcase. 5-80