Installation
1. Before installing the spring on the cylinder heads, check the installed spring height (Diagram A). This is the distance from the bottom of the retainer to the surface where the spring rests on the head. The valves,
retainers and valve locks will be used in this step. First, install the valve in the guide, then install the retainer and valve locks. Pull the retainer tightly against the valve locks while holding the valve assembly steady.
Measure the distance between the spring seat and the outside step of the retainer using your height micrometer (Part #4928 or #4929) or a snap gauge and a pair of calipers. Repeat this procedure for all the valves and record your Information. After you have measured all the valves, find the shortest height. This will become the spring’s installed height on your heads. If your combination includes a dual or triple spring assembly, it will be necessary to allow for the inner steps of the retainer.
2. Once you have determined the shortest installed height, it will be necessary to use shims to obtain this height (±.020” is acceptable) on the remaining valves. These are available through our catalog or at any of
your local COMP Cams® dealers.
3. Before removing the retainers, measure the distance from the bottom of the retainer to the top of the valve seal (Diagram A). This distance must be greater than the lift of the valve. If not, the guide must be machined. This is a very common cause of early camshaft failure. |
4. Once the valve springs have been installed, it is important to check for coil bind. This means that when the valve is fully open, there must be a minimum of .060” clearance between the coils of both the inner and
outer springs. If this clearance does not exist, you must change either the retainer or the valve to gain more installed height, or change to a spring that will handle more lift or machine the spring seat for extra depth.
5. Always check for clearance between the retainer and the inside face of the rocker arm. This will be most evident while the valve is on the seat. Rocker arms are designed to clear specific spring diameters, so you should check to see that you have the proper rocker arm/retainer combination. This situation can also be the result of improper rocker geometry and may be corrected with different length pushrods or a different
length valve.
6. To aid in the engine breaking process, spray the springs, rocker arms and pushrods with COMP Cams® Valve Train Assembly Spray (Part #106).
Breaking In a Spring
1. It is important for new springs to take a heat-set. Never abuse or run the engine at high rpm when the springs are new. Upon initial start-up, limit rpm to 1500 to 2000 until the temperature has reached operating
levels. Shut off the engine and allow the springs to cool to room temperature. This usually will eliminate early breakage and prolong spring life. After the spring has been “broken-in”, it is common for it to lose a slight
amount of pressure. Once this initial pressure loss occurs, the spring pressure should remain constant unless the engine is abused and the spring becomes overstressed. Then the springs must either be replaced or shimmed to the correct pressure. |
