Timing Components: Testing and Inspection

Valve-gear timing






When the pistons in cylinders no. 1 and no. 4 are at top dead centre, the mark on the crankshaft pulley should be in line with the setting mark on the timing cover. When the timing marks on the camshafts are in line with those on the bearing caps, the inlet and exhaust valves for cylinder no. 1 are closed. As the valves open, they extend beyond the face of the cylinder head and into the zone where the pistons change direction. If the setting of the crankshaft and valve gear is altered, the valves and other vital parts of the engine will be damaged.