CPL Racing Dual Valve Springs - K20A K20Z S2000/F20C

Product Information

Valve springs play an important role in controlling the breathing in internal combustion engines. The valves are mechanically opened by a camshaft, via valve lifters or tappets, and closed by the valve springs.


The valve springs perform the following functions;
• Lifting the weight of the valve
• Overcoming friction on the valve shaft when the valve closes creating enough friction, or drag, to keep the valve train and valve following the camshaft profile accurately, by always providing (slightly) greater force than the inertial force of the accelerated mass of the valve. At the same time, the valve-spring forces must not be so large as to create excessive friction on the cam and potential loss of performance.
The force required to keep the valve closed (for a length L1) is referred to as the preload force F1. The force required to maintain accurate camshaft tracking at high revs (for a length L2) is referred to as the spring force F2.


Uprated valve springs are generally subjected to higher loads than standard springs. For this reason, these valve springs are manufactured from special, high-tensile-strength alloys of very high purity according to our own specifications and in our own proprietary production process.

Developed to enable increased lift with reduced weight for high-performance modified engines.