Top dead center (TDC) of the piston of the first cylinder (Mercedes-Benz E-Class W124)

Top dead center of a piston is the point through which each piston passes as the crankshaft rotates. Each piston reaches the TDC position at the end of the compression stroke and again at the end of the exhaust stroke. The TDC of the piston of the first cylinder is used to set the valve timing of the engine.

1. Remove the cylinder head cover.

2. Turn the engine crankshaft with a wrench on the crankshaft pulley mounting bolt until the timing marks align with the pointers.

3. The timing mark on the crankshaft pulley must align with the pointer on the timing chain cover.

4. The groove on the front flange of the camshaft must align with the protrusion on the front camshaft bearing cover.

[Publication taken from an online resource: www.mercedesman.ru]

5. After aligning the timing marks with the pointers, the piston of the first cylinder is at top dead center.