Timing Chain: Service and Repair

Note: As well as the continuous, riveted timing chains, segmented timing chains are available for repairs. These make it possible to replace timing chains without removing and dismantling the engine. Do not fit segmented timing chains simultaneously, but one after the other, as the chains have different senses of direction. The continuous, riveted timing chains should, however be used when reconditioning an engine.

Removing

1. Remove spark plugs, the engine will crank more easily.





2. Set the engine to ignition TDC cylinder 1 (overlapping cylinder 4).

3. Remove chain tensioner, sprocket carrier, guide rails and camshaft sprocket. Procedures

4. Grind through both bolts of a link of the built-in chain and remove the link. Ensure that no grinding dust gets into the engine.

Installing

1. Attach the new chain with the connecting link to the end of the old chain running into the engine when the engine is cranked.

Punch Mark:

930 Mark:

2. Turn the camshaft until the "Center Mark" or "930 Mark" points to approx. 45° outwards. No valves are completely opened when the camshaft is in this position.

3. Turn the crankshaft slowly in the sense of rotation keeping the chain tensioned.

Note: When turning the crankshaft make sure that the valves are not in contact with the piston top. If any pressure is felt, move the crankshaft backwards immediately and adjust the camshaft accordingly.

4. Crank the engine until the connecting pin can be inserted on the other end of the new chain.

5. Remove the old chain and connect the new, drawn-in chain with the connecting pin.





Note: Insert the connecting pin (1) from the front (housing side), not forgetting the spacers. Insert the spring fastening (2) with the closed end pointing in the direction of rotation. Observe the sense of direction of the chains.

6. Install guide rails, sprocket carrier and camshaft sprocket. Procedures

7. Adjust valve timing. Adjustments