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RvP
06-11-2008, 04:46 PM
I am still sorting out my WLA valve spring issues and using the motto of my 7th grade shop teacher, “think three times, measure twice and cut once”, I am still in thinking stage 1. I have some questions for the engine builders in order to move to thinking stage 2:

1) I have a chart that shows 3 spring measurements, free length, valve closed and valve opened. The question is where is this measured? One reference measures valve closed length from the inner face of the valve guide (where the spring sits) to the inner face of the collar (where the spring sits). Another reference measures the distance between the valve lands (the valve lands are the last roll that is flat). Which is correct?

2) Given the valve spring measurements for the valve closed is correct, does that guarantee there will be no coil bind?

3) When preparing a new barrel and pressing in the valve guide, how does a mechanic correct if the measured length of the valve spring when installed is less than the correct length? Do the spring ends get milled down? Do the valve guides have to be removed, the cylinder milled, and then the guides put back in over and over until this is correct?

4) Bonus Question: I have a stock cylinder that is damaged in the bore I am using as an example of what’s right (may be a wild assumption on my part). I made the following observations trying to establish coil bind:
- each turn of the adjusting tappet is 0.028”
- I finger adjust the tappet until it touches the bottom of the valve stem
- I keep increasing the tappet height 1/4 turn at a time (0.007”) until coil bind is felt when the valve is opened.
- Coil bind is felt at 1 turn, which is 0.028”

Now for the question, I have read in a manual that at least 0.060” minimum spring length past the valve open spring length is required to prevent coil bind. Since coil bind occurred at 0.028”, was the previous owner of this barrel lucky it did not coil bind or is 0.028” enough for a WLA?