EngValve Spring Shim, Shim Kit 1.500" OD .645" ID .030" Thick, Valve Spring Shim Kit - 1.500" OD, .645" ID .030" Thickness, None, Ensure the equal installed height of all of your valve springs with these 1.500" outer diameter, .030" thick, heat-treated spring shims., Engine Valve Spring Shim.