Timing Chain: Service and Repair

REMOVAL
1. Disconnect battery negative cable.
2. Remove Timing Chain Cover.





3. Re-install the vibration damper bolt finger tight. Using a suitable socket and breaker bar, rotate the crankshaft to align timing marks as shown in (Fig. 73).
4. Remove camshaft sprocket attaching bolt and remove timing chain with crankshaft and camshaft sprockets.

INSPECTION-MEASURING TIMING CHAIN STRETCH
1. Place a scale next to the timing chain so that any movement of the chain may be measured.
2. Place a torque wrench and socket over camshaft sprocket attaching bolt. Apply torque in the direction of crankshaft rotation to take up slack; 41 Nm (30 ft. lbs.) torque with cylinder head installed or 20 Nm (15 ft. lbs.) torque with cylinder head removed. With a torque applied to the camshaft sprocket bolt, crankshaft should not be permitted to move. It may be necessary to block the crankshaft to prevent rotation.





3. Hold a scale with dimensional reading even with the edge of a chain link. With cylinder heads installed, apply 14 Nm (30 ft. lbs.) torque in the reverse direction. With the cylinder heads removed, apply 20 Nm (15 ft. lbs.) torque in the reverse direction. Note the amount of chain movement (Fig. 74).
4. Install a new timing chain, if its movement exceeds 3.175 mm (1/8 inch).

INSTALLATION
1. Place both camshaft sprocket and crankshaft sprocket on the bench with timing marks on exact imaginary center line through both camshaft and crankshaft bores.
2. Place timing chain around both sprockets.
3. Turn crankshaft and camshaft to line up with keyway location in crankshaft sprocket and in camshaft sprocket.
4. Lift sprockets and chain (keep sprockets tight against the chain in position as described).





5. Slide both sprockets evenly over their respective shafts and use a straightedge to check alignment of timing marks (Fig. 75).
6. Install the camshaft bolt. Tighten the bolt to 68 Nm (50 ft. lbs.) torque.
7. Check camshaft end play. The end play should be 0.051 - 0.152 mm (0.002 - 0.006 inch) with a new thrust plate and up to 0.254 mm (0.010 inch) with a used thrust plate. If not within these limits install a new thrust plate.
8. Install the timing chain cover.