TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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Remove Note. All valve rocker arm covers are removed in the same manner. 1. Separate intercylinder connector flanges (A) from valve rocker arm cover. Note. Use a piece of shim stock to loosen flanges of intercylinder preformed hose. Caution; Do not damage sealing surface on flange of intercylinder preformed hose as it will cause oil leaks and replacement of hose will be required. 2. Remove four bolts (B) and flat washers. 3. Remove seven bolts (C) and flat washers. 4. Remove two screws (D) and flat washers. Note. Before removing rocker arm cover bolts (E), instruction 5, below, the tension on the valve rocker arms, caused by the valve springs. must be released. Turn engine, figure 4-51, until valve rocker arm rollers are on camshaft base circle, or until both valves are closed, to relieve spring tension before removing cover. Check rocker arms to see that they move up and down. If movement (clearance) cannot be felt, turn engine until clearance is evident. When clearance is obtained between both adjusting screw pads and valve stems, the rocker arm rollers are on the camshaft base circle, and the valves are com- pletely closed. 5. Remove four bolts (E) and packings with retainer and remove valve rocker arm cover. Install Note. The cylinder and valve rocker arm cover are machined as an assembly. The number on the rocker cover must be kept with its mating number on cylinder to insure camshaft bearing alinement and running clearance. Note. The bolts and screws securing valve rocker arm cover to cylinder must be torqued carefully to prevent stripping of heli-coil inserts. 1. Position valve rocker arm cover on cylinder and install four bolts (E) and packings with retainer and tighten to 275-325 pounds inch torque. 2. Install two screws (D) and flat washers and tighten to 100 pounds inch torque. 3. Install seven bolts (C) and flat washers and tighten to 100 pounds-inch torque. 4. Install four bolts (B) and flat washers and tighten to 100 pounds inch torque. 5. Position intercylinder connector flanges (A) on valve rocker arm cover. Figure 4-157. Removing or installing valve rocker arm cover bolts and removing valve rocker arm cover. 4-77