i just found a broken valve spring. should i replace all of them or just the one that is broken. the heads were assembled by the machine shop about 8 yrs ago. i have no idea what springs they used. my rocker arms are good and will be reused but i am replacing all the pushrods. i ask about the springs cuz they will be a pain in the a** to change.

ideas????????

 

The others have enjoyed all the same stresses as the one that broke... and of course, since you don't know what they are, you don't even know what to get, to do an exact replacement.

Looks like, from your question, you already know what you need to do.

Might be worthwhile to step up to a bigger spring if you can.

Changing springs is easy, if you have the right tools.

I'd STRONGLY recommend getting yourself a spring height mic and a pile of assorted shims, if you do this yourself; and CAREFULLY setting the installed height on each one, to the spring mfr's ratings. Use the best springs you can get, especially if they're 1.25" (stock dia); DO NOT use GM, K-Motion, stock replacements such as Elgin or Melling, or other cheepies. Get good ones from Comp, Isky, Lunati, Crane, or Crower.

 

thanks for the advice, but unfortunately i'm on a really small budget. it will have to be most likley what the parts store has available. i have never done this before. i don't know how to set the height of them at all.

 

I used to rebuild cylinder heads a few years ago at a machine shop. When you check the height of the spring, you put just the retainer on with the holder keys in place, and place the height micrometer underneath the retainer in place of the spring. You then measure to the nearest .001th of an inch what your height is. Generally speaking, I tried to keep all of them within .002" from each other. That tolerance was generally easy to keep, considering all seats were equally ground. If one goes way higher than the other like 1.700 vs. 1.730, I would put a .030" shim underneath the 1.730 to condense the installed height down to 1.700. Or same goes for 1.715 vs. 1.700 and then a .015 shim under the 1.715 and follow the pattern for other differences. I don't know what your specific manufacturer tolerances are to advise you of what your height should be, but thats the process for checking the height. It was easy for me cuz I never had to check it while it was on the car, but if you could take the heads off and put them on the bench, you'd be better off. Just don't mix up the valves when you take them out, unless you ultimately plan on grinding both the seats and the valves. Hope that helps ya!