Spring Shims - 1.250 OD .050 Thick

PAC Racing Springs Spring Shims 1.250 OD .050 Thick are precision valve spring shims engineered for high-performance engine builds and racing applications. This set of 16 steel shims is designed to fine-tune valve spring pressure and maintain proper valve train geometry in demanding engine configurations. Whether building a street performance engine or preparing a race motor, these shims provide the critical adjustment needed to optimize valvetrain stability and reliability.

Manufactured from quality steel, each shim measures 1.250 inches in outer diameter with a 0.050-inch thickness and 0.570-inch inner diameter. These dimensions are engineered to work with standard valve spring assemblies in small-block and mid-block engine configurations. Spring shim thickness directly affects total spring pressure and seat load—adding shims increases pressure to prevent valve float at higher RPMs, while removing shims reduces pressure to lower stress on valve train components. The 0.050-inch thickness of these shims represents a single-step increment commonly used for fine-tuning pressure in 50-thousandth increments, allowing builders to dial in precise load characteristics without overshooting target specifications.

These shims are essential for engine builders, performance technicians, and racing enthusiasts who need to customize valve spring pressure for specific camshaft profiles and RPM ranges. Proper spring shim selection prevents valve float, reduces wear on rocker arms and pushrods, and ensures consistent valve timing under extreme load. The set of 16 provides flexibility to experiment with pressure combinations or equip multiple cylinders with matched shim stacks for balanced valvetrain performance across the engine.

Spring shims are a foundational component in any serious engine build requiring valvetrain optimization. PAC Racing Springs is recognized in the performance engine community for precision manufacturing and consistency. Whether upgrading to a higher-lift camshaft, increasing engine displacement, or preparing for competition, having quality shims on hand allows rapid pressure adjustments to match your specific build requirements and power goals.