Valve Rotator: Service and Repair

Fig. 18 Cylinder head exploded view:

Fig. 21 Checking valve stem for rotator malfunction:

The rotator operates on a sprag clutch principle utilizing the collapsing action of coil spring to give rotation to the rotor body which turns the valve, Fig. 18.
To check rotator action, draw a line across rotator body and down the collar. Operate engine at 1500 RPM, rotator body should move around collar. Rotator action can be in either direction. Replace rotator if no movement is noted.
When servicing valves, valve stem tips should be checked for improper wear pattern which could indicate a defective valve rotator, Fig. 21.