Timing Chain: Testing and Inspection

STANDARD PROCEDURE-MEASURING TIMING CHAIN WEAR

NOTE: This procedure must be performed with the timing chain cover removed.

1. Remove the timing chain cover.





2. To determine if the secondary timing chains are worn, rotate the engine clockwise until maximum tensioner piston extension is obtained. Measure the distance between the secondary timing chain tensioner housing and the step ledge on the piston (Fig. 123). The measurement at point (A) must be less than 15 mm (0.5906 inches).
3. If the measurement exceeds the specification the secondary timing chains are worn and require replacement.

NOTE: If the secondary chains are to be replaced the primary chain must also be replaced.

INSPECTION
Inspect the following components:
- Sprockets for excessive tooth wear. Some tooth markings are normal and not a cause for sprocket replacement.
- Idler sprocket assembly bushing and shaft for excessive wear.
- Idler sprocket assembly spline joint. The joint should be tight with no backlash or axial movement.
- Chain guides and tensioner arms. Replace these parts if grooving in plastic face is more than 1 mm (0.039 inch) deep. If plastic face is severely grooved or melted, the tensioner lube jet may be clogged. The tensioner should be replaced.
- secondary chain tensioner piston and ratcheting device. Inspect for evidence of heavy contact between tensioner piston and tensioner arm. If this condition exist the tensioner and tensioner arm should be replaced.





- Primary chain tensioner plastic faces. Replace as required (Fig. 140).