VALVE SPRING SHIMS are designed to reduce valve spring installed height. They are used to establish the distance between the spring base and spring retainer, known as "target" installed height. Setting up valve spring installed height is vital to valve spring performance and should never be assumed correct, a measurement is highly recommended for most applications. The general tolerance is +/- .010" Some applications may required different tolerances.
Several manufacturers offer a tool to measure valve spring installed height. A common name for this tool is: Valve spring heigth "Mic" or spring installed height tool. Although less accurate, D.I.Y.er's can make up their own measuring rod from a 20 penny nail cut to size. An pair of calipars are required to properly establish the rods length. Cut the nail slightly longer than final length then grind the ends with a slight radius. Rounded ends will produce more accurate results then square cut ends.
We offer shims in both types, standard or hardened. High Spring Pressures and or racing applications normally use hardened shims. Depending on the pressures and application, some perf engines do fine with standard shims. The difference between them is their hardness. The Hardened shims go through a special heat treat process which makes them more resistant to wear.
Our hardened shims come in two different colors, Blue and Black while our standard shims come in: Silver, Copper, Gold and Black. Buyers are attracted to standard shims because they are less expensive than their hardened counterpart.
Our Valve Spring Shims come in three different thickness's.
We normally carry them in:
We list spring shims two ways; application and size. Application coverage will only display popular domestic applications. If you do not see your application, we suggest measuring the spring base to determine which shim will fit under your spring. If this is not possible, you can e-mail tech for a suggestion. We will try to look it up for you. Taking a measurement is always best as some factory heads may have been previously machined for larger diameter springs.
FITMENT: Spring shims are not required to be the same diameter as the spring. They can be larger as well as smaller on the ID/OD diameters. It is acceptable for the spring to overhang the shim by a certain amount. Springs can be as much as .120" larger [.060" per side overhang] than the shim. Naturally, the shim can be larger than the spring as long as it fits the heads spring base. What is important is for the shim to fit on the spring base so it can sit all the way down. When setting up spring installed height, the goal is to get it as close as possible to the target height. Tolerance is normally around +/- .010"