Camshaft Timing Chain Inspection

Special Tools

• EN-952:  Fixing Pin
• EN-953-A:  Fixing Tool
• EN-49977-100:  Transmitter Disc Fixation

For equivalent regional tools, refer to Special Tools .

1. Remove the ignition coil. Refer to Ignition Coil Removal .
2. Remove the camshaft cover. Refer to Camshaft Cover Removal .
Fig 1: Bore And Mark
Courtesy of GENERAL MOTORS CORP.
3. Rotate the engine clockwise until the bore (2) in the crankshaft balancer aligns with the mark (1) on the engine front cover.
Fig 2: Camshaft Grooves
Courtesy of GENERAL MOTORS CORP.
4. Examine that the camshaft grooves (1) are visible as shown. If the camshaft grooves are not visible rotate the crankshaft 360°.
Fig 3: Crankshaft Bearing Cap Tie Plate Hole Plug And Seal Ring
Courtesy of GENERAL MOTORS CORP.
5. Remove the crankshaft bearing cap tie plate hole plug (2) and the seal ring (1).
Fig 4: Fixing Pin
Courtesy of GENERAL MOTORS CORP.
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.
6. Install EN-952:  fixing pin (1) to hold the crankshaft in TDC position.
Fig 5: Fixing Tool
Courtesy of GENERAL MOTORS CORP.
NOTE: The fixing tool should be installed completely to both camshaft grooves without high effort.
7. Install EN-953-A:  fixing tool (1) to the camshafts.
Fig 6: Transmitter Disc Fixation And Bolts
Courtesy of GENERAL MOTORS CORP.
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 (4).
8. Install EN-49977-100:  transmitter disc fixation (1) to inspect the correct position of the camshaft position exciter wheels.
9. Tighten the bolts (2) of EN-49977-100:  transmitter disc fixation.
10. If EN-953-A:  fixing tool or EN-49977-100:  transmitter disc fixation can not be installed, refer to Camshaft Timing Chain Adjustment .
11. Remove EN-49977-100:  transmitter disc fixation.
12. Remove EN-953-A:  fixing tool.
13. Remove EN-952:  fixing pin.
CAUTION: Refer to Fastener Caution .
14. Install crankshaft bearing cap tie plate hole plug and seal ring and tighten to 40 N.m (30 lb ft).
15. Install the camshaft cover. Refer to Camshaft Cover Installation .
16. Install the ignition coil. Refer to Ignition Coil Installation .