Shims

Are you a fraction of a millimetre away from hitting the target valve clearance or camber? Shims are thin, precise spacers that move a part by a controlled amount. Here they are divided into engine shims and suspension shims, for you who do your own adjustments in the workshop or garage.

Engine shims and suspension shims – what do they do?

Engine shims are typically used to set a clearance, e.g. between camshaft and valve, where the thickness determines the result. Hot Cams, for example, offers shim kits in thicknesses such as 1.250, 1.500 and 1.750 mm, both as 5-packs and as complete kits. Suspension shims are typically placed in the suspension to change camber or caster. SPC Performance, for example, offers 1 mm camber/caster shims. The category also includes brands such as COMP Cams, Supertech and S&S Cycle.

How to choose the right shim

First measure the current clearance or angle, and calculate how much needs to be changed. After that, the choice depends on several factors:

• Thickness: small increments allow finer adjustment but require precise measurement.
• Size and shape: the shim must fit the seat or mounting surface, otherwise it can shift.
• Material: e.g. steel must be able to withstand the load at the specific location.
• Stacking: several shims on top of each other should only be used where the manufacturer allows it.

Installation, checks and related parts

After installing engine shims, the clearance should be measured again. With suspension shims, the wheel alignment should be checked, as camber and caster can affect tracking and tyre wear. If the bolts are not tightened to the specified torque, the shims can settle. If you need new bolts, nuts or washers for the same project, you will find them in the related categories.

Frequently asked questions

What is the difference between engine shims and suspension shims?

Engine shims are typically used to set a clearance inside the engine, e.g. at the valves. Suspension shims are fitted in the suspension to adjust angles such as camber and caster. They cannot be used in place of each other.

How do I find the shim thickness I need?

Measure the current clearance and compare it with the specified value. Then adjust the thickness of the fitted shim by the difference. Use the values for your specific engine, and always measure again after installation.

Should the wheel alignment be checked after fitting camber shims?

Yes. A change in camber or caster can affect tracking and tyre wear. The wheel alignment should therefore be checked and adjusted if necessary once the shims are fitted and the bolts are correctly tightened.

Can I reuse old shims?

It depends on wear and type. A deformed, scratched or worn shim can give incorrect clearance or settle. Measure the thickness with a micrometer before you reuse it.