Valve springs are one of the most critical components of your engine. It is very important to match the camshaft and potential RPM range with the correct spring rate, which we will attempt to explain in this article in laymen terms. First, lets cover a little valve spring terminology.

• Free Height - the overall height of the spring in an unloaded condition (when the spring is sitting on the workbench).
• Installed Height - the overall height of the spring in a loaded condition (when the spring is installed on the cylinder head).
• Open Height - the height of the installed spring when the valve is in a fully open position (when the spring is installed on the cylinder head).
• Solid Height - the overall height of the spring in a fully compressed condition (when every coil touches the adjacent coils, above and below).
• Coil bind - the difference between the installed height and the solid height, (rule of thumb - maximum valve lift equals Coil Bind minus 10 percent).
• Seat/Closed Pressure - the specified load (by design) on the spring when the valve is in a fully closed position, measured in lbs per square inch.
• Nose/Open Pressure - the specified load (by design) on the spring when the valve is in a fully open position, measured in lbs per square inch.
• Spring Rate - the amount of weight required to compress the spring by one inch, rated in lbs/sq.in. (not to be confused with Spring Rating - see below).
• Spring Rating - specifies load when fully closed (Seat Pressure) and fully open (Nose Pressure), may be a range or a specific number. Example: 80-85/160-165 or 80/160.
• Load @ Open Height - the actual load on a spring, when the valve is in a fully open position (replace spring if not within 10% of the minimum specified Open Pressure).

Single Springs with Dampers, and Dual Springs are recommended for use in higher revving engines with medium to high lift aftermarket camshafts. They offer increased rates for elimination of valve float at higher RPM's, reducing coil bind in high lift applications, yet offer increased safety in the event of spring breakage. The dampers also reduce damaging harmonics in the valve train. Valve spring cups are recommended for all springs, and must be used on our aluminum heads to validate the warranty. Maximum Valve Lift (combined total): 0.700" 

Spring Retainers: We recommend and stock, light weight one piece spring retainers, which fit all of our valve springs.

Note: Installation of our single springs with dampers, and/or dual springs, may require machining to eliminate the cylinder head valve step on a stock cast iron cylinder head, which was intended to keep the stock single springs in correct alignment.

Note: To install .500 Viton seals, a valve cutter must be used to machine the valve guides, this helps to keep the seals securely seated on the guides once installed (.530 seals do not require maching). The .500 Viton seals are recommended when using dual spings, such as our CSC-200-TOY, as they increase the clearance between the seal and inner spring.