Valve springs and valves

[dan filipi]

Well I pretty much know how to do valve lapping, actually depending how much it'll cost I might have a shop do it together with new valve guides.

My question here is about springs.

We had a discussion going about valve springs and finding a suitable replacement for them cheaper than OEM.
Did we ever come to a conclusion on that?

If I were to run old springs, is checking them against spec's enough?
It seems to me if the uncompressed height and compressed (installed) height is within spec they would be ok,
is there more to it than that?

BTW, I may be running the 1200 cams in these reconditioned heads if that changes anything.
Please don't tell me all bet's are off :beg:

 

[mcgovern61]

There are two things to check on the springs, the allowable length (in the shop manual) and compression rate. Just because the spring might be within spec for length, it does'nt mean that it will have the strength left to work against the valves. I found my '81 inner springs to be way below spec when I measured them. Based on that alone, I assume the outer springs were unspring too?

 

[slabghost]

Coil springs have consistent resistance ( maybe wrong terminology). But in effect it means that if the spring has 50# at seat height and free length is 1/2 " longer then it would have 25# resistance for every 1/4 " of compression. So if the valve has 1/2" travel full open then at that point the spring has 100# return pressure. I added seat preload to another 1/2" travel. Sounds simple but the stock valve are dual spring. Inside spring is the buffer spring. Best option for stock performance is all new OEM springs. I included a link to a full set at a reasonable price in the other thread. From Honda they are about $7-8 per spring with two needed at each valve. Testing of alternative car springs has not been done yet.