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:
1.800 Installed spring height
-0.500 maximum valve lift
=1.300 Compressed spring height
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:
1.300 Compressed spring height
-1.200 Solid height
=0.100 Compressed spring clearance
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.
Shims come in 0.015-, 0.030-, and 0.060-inch sizes. If you're 0.005 short, that's OK; if you're 0.010 short, use a 0.015 shim to come in at 0.005 over.
Taking 0.006 inch off the head surface decreases the chamber volume by 1cc.
If you're not having a valve job done, each valve must go back in its original spot.
Use a spring locator instead of a .060-inch shim. it'll positively locate the spring, and its extra durability will protect the head surface.
When the layout dye is dry, each valve was placed against its seat and twisted for approxi
This is what a properly fitting valve/seat intersection should look like. The outline crea
Next on the agenda is establishing the valvespring installed height. If you know what cam
When checking this spec with a height mic, be sure to use the retainer and locks you'll be
We're right on our 1.800-inch figure, but only because Alvarez uses a hardened steel sprin
If you're using a head that doesn't have a pocket for a spring cup, Comp makes hardened st
Speed-O-Motive uses high-quality, positive-lock valve seals when it builds its heads. If y
Seals in place and installed height established, Alvarez proceeded to install the valves i
Before installing the springs, it's a good idea to check spring pressure, using the same r
The last step (but one) is to install the valvesprings. Alvarez does have an air-powered s
FOR THE DIYER V-style head holder $36; Valve Spring Tray $30; Mini Spring Tester $79; Smal
UNDER PRESSURE Not too many home builders are willing-or able-to drop six-and-a-half bills
WE LIKE MIC Measuring valve-guide clearance is critical to building a solid set of heads.
Insert the proper tool from Powerhouse's Small Hole Gauge Set into a valve guide, tighten