How to find the right Automotive Performance Engine Valve Shims AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Automotive Performance Engine Valve Shims
- Shim type and diameter
- Confirm whether the engine uses under-bucket or over-bucket shims, and match the exact shim diameter. Wrong shims can spit out or leave the cam lobe riding the bucket edge.
- Thickness calculation
- Measure lash with feeler gauges, then calculate new thickness from the existing shim and the spec. Guessing wastes shims and leaves the clearance incorrect.
- Hardness
- Use hardened tool-steel shims for performance cams and springs. Soft shims wear quickly and the lash drifts.
- Spring seat shims
- Use spring seat shims under the spring to correct installed height. They are a different part with the same name, so check which one you need.
Brands that matter
- Supertech: Shim kits for import DOHC engines.
- Ferrea: Shims and buckets for import performance heads.
- Brian Crower: Valvetrain shims for import builds.
- COMP Cams: Spring seat shims for setting installed height.
What to avoid
- Mixing shim diameters
- Reusing worn shims after a cam change
- Assuming lash shims and spring seat shims are interchangeable
Questions
Are valve shims for lash or for spring height?
Both exist: lash shims in bucket engines set valve clearance, while spring seat shims under the spring set installed height and pressure.