MILD THUNDER

iTrader: (3)

First you/we need to know what block you have. Second, what heads you have.

Before selecting a valve spring, you need to get some measurements. What size are the spring pockets? What is your install height for the springs? If you are limited on install height , this can affect/limit your spring choice. Once you know what you can physically fit for a spring, the next step is to figure out what spring pressures you want. And when picking a spring, you'll want to be sure you pick one that is a reasonable distance from coil bind. Obviously too close is not good, but too far isnt good either. I had springs that had plenty of pressure for my application, but were totally wrong for the setup. They were damn near 1/4" away from coil bind. The springs walked around like crazy. A properly setup spring with less pressure, can be more effective at controlling and stabilizing the valvetrain than an incorrect one with higher pressures.

Comp Cam’s Billy Godbold notes that “from high-speed video and testing, it is clear that adjacent coils contact as you approach the valvetrain-limiting speed (this is known as spring surge). Hence, modern springs are designed to run near coil bind and use the coil-to-coil interaction for improved damping at or near max lift. This interaction is one of the most effective means of dampening spring surge, but the spring must be properly designed in terms of solid stress to safely use this interaction.” Depending on the intended use and the spring and cam-lobe design, coil-bind safety margins can now vary from 0.015 to 0.120 inch, with tighter numbers predominating on very stiff valvetrains. Anything more than 0.150 inch may cause spring surge, which can greatly reduce the available spring load needed to close the valve.