1.a garter spring rotating device to longer lifetime of valve 2 matched 1- 20 cylinder engines 3, OE quality,competitive ... of opening and closing of the valve.2. In this course it make the valve, valve seat, valve guide to lap each ohter and ... leakage"/"snap".4. on the same condition, valve lifetime is lengthened 3 times. Tianxuan’s Valve rotator is supplying more than 20 engine ...