Description

Copper shims, total of (2), for the upper timing chain tensioner for all SR311 and SRL311 model roadsters with the U20 engine. Copper was chosen for the shim material since it is softer than the hard chrome finish on the piston shaft of the tensioner foot. Aftermarket.

These copper shims slide onto the piston shaft on the back of the tensioner foot to prevent the foot from fully retracting into the tensioner housing due to low oil pressure (which normally occurs at idle) or normal chain stretch due to wear. The I.D. of the shim is just slightly larger than the piston shaft so they slide on easily and the O.D. is just slightly smaller than the rubber gasket that cushions the foot against the housing upon retraction so these shims don’t need to be trimmed and they don’t interfere with the tensioner backing plate either! The rubber cushioning washer sometimes supplies isn’t designed to shim out the foot but rather to prevent the foot from slamming back into the tensioner body.

A quick, inexpensive solution to the “death rattle” problem of the U20 engine; these are a wise purchase to prevent engine damage (pistons, valves, front cover, cam cover, etc.) due to “chain slap”. Depending on the amount of chain stretch, you may need anywhere from 1 – 4 of these shims; each shim measures approximately 0.086″ thick.