Timing Chain: Service and Repair
Timing Chain, Sprockets, and/or Tensioner ReplacementTools Required
^ J 36660-A Torque Angle Meter
^ J 44221 Camshaft Holding Tool
Removal Procedure
1. Remove the camshaft cover.
2. Remove the engine front cover.
3. Release the tension on the timing chain by moving the tensioner shoe inch).
4. Place the tee into the tensioner to hold the shoe in place.
5. Remove the top chain guide bolts.
6. Remove the top chain guide.
7. Remove the exhaust camshaft position actuator bolt.
8. Remove the exhaust camshaft position actuator.
9. Remove the intake camshaft sprocket bolt.
10. Remove the intake camshaft sprocket.
11. Remove the timing chain.
12. Remove the crankshaft sprocket.
13. Remove the cylinder head access hole plugs.
14. Remove the timing chain tensioner shoe bolt.
15. Remove the timing chain tensioner shoe.
16. Remove the timing chain tensioner guide bolts.
17. Remove the timing chain tensioner guide.
18. Remove the timing chain tensioner bolts.
19. Remove the timing chain tensioner.
Installation Procedure
Notice: Refer to Fastener Notice in Service Precautions.
Important: Every seventh link of the timing chain is darkened to aid in aligning the timing marks.
1. Install the timing chain tensioner and secure the tensioner with the bolts.
^ Tighten the timing chain tensioner bolts to 25 Nm (18 ft. lbs.).
2. Install the timing chain tensioner guide and secure the guide with the bolts.
^ Tighten the timing chain tensioner guide to 10 Nm (89 inch lbs.).
3. Install the timing chain tensioner shoe and secure the shoe with the bolt.
^ Tighten the timing chain tensioner shoe bolt to 26 Nm (19 ft. lbs.).
4. Install the cylinder head access hole plugs.
^ Tighten the cylinder head access hole plugs to 5 Nm (44 inch lbs.).
5. Install the J 44221 with the camshaft flats up and the number 1 cylinder at top dead center.
6. Install the crankshaft sprocket (1).
7. Install the intake camshaft sprocket into the timing chain.
8. Align the dark link of the timing chain with the timing mark on the intake camshaft sprocket (1).
9. Feed the timing chain down through the opening in the head.
10. Install the timing chain on the crankshaft sprocket. Align the dark link of the timing chain with the timing mark on to the crankshaft sprocket.
Important: It may be necessary to remove J 44221 to rotate and hold the camshaft (hex) to align the pin to the camshaft
11. Install the intake camshaft sprocket onto the intake camshaft.
12. Install the intake camshaft sprocket washer and bolt.
13. Install the exhaust camshaft actuator into the timing chain.
14. Align the dark link of the timing chain with the timing mark on the exhaust camshaft actuator (1).
Important: It may be necessary to remove the J 44221 to rotate and hold the camshaft hex to align the pin to the camshaft sprocket
15. Install the exhaust camshaft actuator onto the exhaust camshaft.
Important: Rotate the camshaft clockwise relative to the camshaft prior to tightening the bolt
16. Rotate the camshaft actuator clockwise until it stops (as seen from the front of the vehicle).
Notice: The camshaft actuator must be fully advanced during installation. Engine damage may occur if the camshaft actuator is not fully advanced.
17. Install the exhaust camshaft actuator bolt.
^ Tighten the exhaust camshaft actuator bolt the first pass to 25 Nm (18 ft. lbs.).
^ Use J 36660-A to tighten the exhaust camshaft actuator bolt the final pass an additional 135 degrees.
18. Tighten
^ Tighten the intake camshaft sprocket bolt the first pass to 20 Nm (15 ft. lbs.).
^ Use J 36660-A to tighten the intake camshaft sprocket bolt the final pass an additional 100 degrees.
19. Remove the tee in the timing chain tensioner to regain tension on the timing chain.
20. Remove the J 44221.
21. The dark lines (1) on the chain should be aligned with the marks on the sprockets as shown.
22. Install the top chain guide.
23. Add threadlock GM P/N 12345496 on the top chain guide bolt threads.
24. Install the top chain guide bolts.
^ Tighten the top chain guide bolts to 10 Nm (89 ft. lbs.).
25. Install the engine front cover.
26. Install the camshaft cover.