Valvetrain, Servicing

Valvetrain, servicing

Note:
^ Cylinder heads with cracks between the valve seats, or between the valve seat and the spark plug threads, can continue to be used without reducing the service life, as long as the cracks have a width of max. 0.3 mm, or only the first 4 threads of the spark plug threads are cracked.
^ Cylinder head and guide frame may only be replaced together.
^ Do not re-grind valve seats in cylinder head, only hand-lapping valves is permitted.
^ After installing the camshafts, the engine may not be started for approx. 30 minutes. The hydraulic equalization elements must seat themselves (otherwise the valves will crash into the pistons).
^ After working on the valvetrain and lifters, carefully rotate the crankshaft by hand at least 2 full revolutions before starting to be sure that valves do not strike the pistons.
^ Always replace gaskets and seals.