Timing marks for valve timing (Audi A6 C4)

The crankshaft, camshaft and intermediate shaft sprockets are driven by the timing belt and rotate in phase.

If the sprockets are out of phase, the valves will touch the pistons as the crankshaft rotates.

The top dead center is taken to be the highest point reached by piston N1 during the compression stroke.

Execution order

1. By aligning the synchronization marks, set piston N1 to TDC to ensure the rotation of the sprockets is in phase.





2. To set piston N1 to TDC, remove the top engine cover.



3. Remove the distributor cap and mark the position of the N1 cylinder wire.

4. Remove all spark plugs.

5. Turn the crankshaft clockwise and determine when the piston makes the compression stroke.

6. Continue to turn the crankshaft until the timing marks on the camshaft sprocket and flywheel are aligned with the corresponding marks on the belt cover and gearbox.

(The text is based on materials from the website «AUDIMANUAL»)