Performance Cylinder Heads - Some Assembly Required

Under Pressure
Not too many home builders are willing-or able-to drop six-and-a-half bills on a full-fledged bench-top valvespring tester. Luckily, Powerhouse Products has a low-buck alternative. This mini spring tester is easy to use. Simply place a spring and the tester in a vice (as shown), then compress the spring to its installed height (or the height you're checking), as measured with calipers. The gauge will give you the spring pressure-in this case, 110 pounds. Nice. An inexpensive flange allows the tester to be used in a drill press.

We Like MIC
Measuring valve-guide clearance is critical to building a solid set of heads. An outside mic for checking the valve stems is relatively inexpensive; an inside mic, for the guides, no so much. Again, here's a low-buck alternative. Insert the proper tool from Powerhouse's Small Hole Gauge Set into a valve guide, tighten the knob until the end fits the guide, then remove the tool and measure the ball tip with your outside mic. Voila, you've got your valve-guide dimension.

Checking For Coil Bind
It's imperative to make sure that the valvesprings you're using can handle the cam you're using. If the spring binds, or becomes "stacked," you can end up with a lunched cam. So, while you're compressing springs, here are two ways to check for coil bind:

With the spring at its compressed height, you should have a minimum of 0.060 inch clearance between the coils, measured with a feeler gauge.

You can also compress the spring until it is completely compressed ("solid height"), make a measurement, and subtract this figure from the compressed spring height. For example:

And as it turns out, 0.100 inch is the minimum clearance you should have. Whatever method you use, this is an easy way to ensure valvetrain longevity.