Duramax LLY – PUSHROD, ROCKER ARM AND SHAFT INSTALLATION

NOTE: The rocker arm end of each pushrod is identified with a paint stripe. In addition, the ball at this end of the pushrod is heat treated/coated giving it a distinctive color. Be sure the pushrods are installed with the correct end up and toward the rocker arm.

1. Insert pushrods in roller lifters. Verify that all pushrods are correctly installed.

2. Index crankshaft and pistons for rocker arm shaft installation as follows:
a. Position breaker bar and socket on crankshaft damper bolt. Do not use starter to rotate crankshaft. Turn shaft with hand tools only.
b. Rotate crankshaft counterclockwise, and align mark on torsional damper with “O” mark on front cover timing tab (Figure 2-180).
c. Rotate engine counterclockwise an additional 3 1/2 inches (89 mm), measured at mark on torsional damper. Damper mark should align with water pump first, lower attaching bolt at this point (Figure 2-176).

3. Align and install rocker arm and shaft assemblies (Figure 2-181). Be very sure pushrods are seated in lifter and in rocker arms. Also be sure rocker arm retainers are in place and seated.

4. Install rocker arm shaft retainers and bolts. Tighten bolts in small increments until snug, with socket and ratchet or nut runner.

CAUTION: Do not use an air wrench to tighten the bolts. In addition, stop tightening if the bolts become hard to turn before they are seated. If this condition occurs, the crankshaft and pistons are not properly indexed, allowing the valves to contact the pistons.

5. Verify that pushrods are properly seated in rocker arms and lifters. Then final-tighten rocker arm shafts bolts to 41-lb-ft (56 N•m) torque.

 

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