68. Timing Chain and Sprocket Installation

Timing Chain and Sprockets Installation

^ Tools Required
- J 44221 Camshaft Holding Tool
- J 45059 Angle Meter





1. Install J 44221 with the camshaft flats up and the number 1 cylinder at top dead center. The crankshaft pin should be at 12 o'clock when the number 1 piston is at top dead center.





2. Compress the tensioner and lock in place.
3. Install the crankshaft sprocket.
4. Install the intake camshaft sprocket into the timing chain.
5. Align the (dark) link of the timing chain with the timing mark on the intake camshaft sprocket (1).
6. Feed the timing chain down through the opening in the head.
7. Install the timing chain onto the crankshaft sprocket. Align the (dark) link of the timing chain with the timing mark on the crankshaft sprocket (2).

8. Install the intake camshaft sprocket onto the intake camshaft.

Important: It may be necessary to remove J 44221 to rotate and hold the camshaft (hex) to align the pin to the camshaft sprocket.






9. Install the intake camshaft sprocket washer and new bolt.
^ Tighten the new intake camshaft sprocket bolt the first pass to 20 Nm (15 ft. lbs.).
^ Use J 45059 to tighten the intake camshaft sprocket bolt the final pass an additional 100 degrees.

Notice: Refer to Fastener Notice in Service Precautions.






10. Install the exhaust camshaft actuator into the timing chain.
11. Align the (dark) link of the timing chain with the timing mark on the exhaust camshaft actuator (1).

12. Install the exhaust camshaft actuator onto the exhaust camshaft.

Important: It may be necessary to remove J 44221 to rotate and hold the camshaft (hex) to align the pin to the camshaft sprocket.


13. Install the new exhaust camshaft actuator bolt.
^ Tighten the new exhaust camshaft actuator bolt the first pass to 25 Nm (18 ft. lbs.).
^ Use J 45059 to tighten the exhaust camshaft actuator bolt the final pass an additional 135 degrees.

Notice: The camshaft actuator must be fully advanced during installation. Engine damage may occur if the camshaft actuator is not fully advanced.

Important: Rotate the camshaft actuator clockwise relative to the camshaft prior to tightening the bolt.

14. Unlock the tensioner.
15. Remove J 44221.





16. Rotate the camshaft actuator clockwise (as seen from the front of the vehicle).

Important: Rotate the camshaft actuator clockwise relative to the camshaft prior to tightening the bolt.






17. The dark links (1) on the chain should be aligned with marks on sprockets as shown.





18. Install the top chain guide.
19. Add threadlock GM P/N United States 12345498, GM P/N Canada 10953488 to the top chain guide bolt threads.
20. Install the top chain guide bolts.
Tighten the top chain guide bolts to 10 Nm (89 inch lbs.).