Valve Gear, Servicing

Valve gear, servicing

Note:
^ Cylinder heads with cracks between valve seats or between valve seat and spark plug thread can still be used without loss of service life if the cracks are minute (max. 0.3 mm width) or only the first four threads of a spark plug thread are cracked.
^ After installing camshafts, do not start engine for at least 30 minutes. The hydraulic valve lifters have to settle (otherwise valves will strike the pistons).
^ After working on the valve gear, carefully rotate engine by hand at least 2 full revolutions to ensure that valves do not strike the pistons when starting.
^ Always replace seals and O-rings.