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.

Locking the shaft with a homemade device

1. To set piston N1 to TDC, unscrew the glow plugs.

2. Turn the crankshaft and align the timing mark on the flywheel with the protrusion on the gearbox casing and the mark on the fuel pump sprocket with the mark on the pump housing.





3. Using special tools, lock the camshaft (see also fig. Locking the shaft with a homemade device).





4. Center the locked camshaft using feeler gauges. Now, piston N1 is at TDC.