Camshaft Timing Chain Adjustment

Special Tools

• EN-952  Fixing Pin
• EN-953-A  Fixing Tool
• EN-49977-100  Fixation Sensor Discs

For equivalent regional tools, refer to Special Tools .

1. Remove the ignition coil. Refer to Ignition Coil Replacement .
2. Remove the camshaft cover. Refer to Camshaft Cover Replacement .
3. Remove the camshaft position actuator solenoid valves. Refer to Camshaft Position Actuator Solenoid Valve Replacement .
4. Remove the right front wheelhouse liner. Refer to Front Wheelhouse Liner Replacement (Chevrolet)Front Wheelhouse Liner Replacement (Buick) .
Fig 1: Bore And Mark
Courtesy of GENERAL MOTORS COMPANY
5. Rotate the engine clockwise until the bore (2) in the crankshaft balancer aligns with the mark (1) on the engine front cover.
Fig 2: Crankshaft Bearing Cap Tie Plate Hole Plug And Seal Ring
Courtesy of GENERAL MOTORS COMPANY
6. Remove the crankshaft bearing cap tie plate hole plug (2) and the seal ring (1).
Fig 3: Fixing Pin
Courtesy of GENERAL MOTORS COMPANY
CAUTION:

To ensure proper crankshaft top dead center (TDC) alignment, the retention pin should fit easily through the bore in the crankshaft tie plate and into the crankshaft. Binding of the retention pin could affect proper engine timing.

7. Install the EN-952  fixing pin (1) to hold the crankshaft in TDC position.
Fig 4: Intake Camshaft Sprocket Bolt And Wrench
Courtesy of GENERAL MOTORS COMPANY
8. Loosen the intake camshaft sprocket bolt (2) while holding the hexagon of the intake camshaft with a wrench (1) until the camshaft position exciter wheel is clearly rotatable.
9. Loosen the exhaust camshaft sprocket bolt while holding the hexagon of the exhaust camshaft with a wrench until the camshaft position exciter wheel is clearly rotatable.
Fig 5: Fixing Tool
Courtesy of GENERAL MOTORS COMPANY
NOTE:

The fixing tool should be installed completely to both camshaft grooves without high effort.

10. Adjust the camshafts so that the EN-953-A  fixing tool (1) can be installed.
Fig 6: Upper Timing Chain Guide And Bolts
Courtesy of GENERAL MOTORS COMPANY
11. Remove the 2 upper timing chain guide bolts (1).
12. Remove the upper timing chain guide (2).
Fig 7: Intake Camshaft Sprocket Gearing And Special Tool
Courtesy of GENERAL MOTORS COMPANY
NOTE:

Push the fixing tool in the direction of the arrow to ensure it engages without clearance.

13. Install the EN-49977-200  fixing tool (2) and adjust the gearing of the fixing tool so it engages with the intake camshaft sprocket gearing (1).
Fig 8: Adjuster Bolt And Fastening Bolts
Courtesy of GENERAL MOTORS COMPANY
14. Tighten the 2 fastening bolts (1) of the EN-49977-200  fixing tool while pushing the fixing tool in direction of the arrow.
15. Tighten the adjuster bolt (2).
Fig 9: Fastening Bolts And Fixation Tool
Courtesy of GENERAL MOTORS COMPANY
NOTE:

A wrong installation position is possible. Make sure that the fixation tool is installed without clearance to the cylinder head in areas (3) and (5).

16. Install the EN-49977-100  fixation (2) to find and hold the camshaft position exciter wheels in the correct position.
17. Tighten the 2 fastening bolts (6) of the EN-49977-100  fixation.
CAUTION:

Refer to Fastener Caution .

18. Tighten the intake camshaft sprocket bolt (4) while holding the hexagon (1) of the intake camshaft to 50 N.m (37 lb ft).
19. Tighten the intake camshaft sprocket bolt (4) while holding the hexagon (1) of the intake camshaft an additional 60°.
20. Tighten the exhaust camshaft sprocket bolt while holding the hexagon of the exhaust camshaft to 50 N.m (37 lb ft).
21. Tighten the exhaust camshaft sprocket bolt while holding the hexagon of the exhaust camshaft an additional 60°.
22. Remove the EN-49977-100  fixation and the EN-49977-200  fixing tool.
Fig 10: Upper Timing Chain Guide And Bolts
Courtesy of GENERAL MOTORS COMPANY
23. Install the upper timing chain guide (2).
24. Install the 2 upper timing chain guide bolts (1) and tighten to 8 N.m (71 lb in).
25. Remove the EN-953-A  fixing tool.
26. Remove the EN-952  fixing pin.
27. Rotate the crankshaft for 720° and check the engine timing again. Repeat the adjustment procedure if necessary.
28. Install the crankshaft bearing cap tie plate hole plug and seal ring and tighten to 40 N.m (30 lb ft).
29. Install the right front wheelhouse liner. Refer to Front Wheelhouse Liner Replacement (Chevrolet)Front Wheelhouse Liner Replacement (Buick)
30. Install the camshaft position actuator solenoid valves. Refer to Camshaft Position Actuator Solenoid Valve Replacement .
31. Install the camshaft cover. Refer to Camshaft Cover Replacement .
32. Install the ignition coil. Refer to Ignition Coil Replacement .