Inliners International Forums General Discussion Engines Valve spring washers, thrust bearings?

They were originally developed for heavy duty truck type motors that really work for a living i.e. dump truck, school bus, etc. to help extend exhaust valve seat life (the most likely valve to burn) Olds and some others used them in some pass car motors too. I supposed they can fail-but they do add SOME weight to the valve train and therefore can lower rpm level of valve float,and should not be used with any non-stock camshaft. The flat washer type BELOW the spring is offered in various thicknesses and is used to set up correct valve spring installed heights-critical in setting up correct rocker arm geometry.

Any machine shop that grinds valves will carry an assortment of the spring seat shims. Probably not the rotators.