602 crate valve springs

I run in a street stock style class, bought a new 602 in February 2017. I have 2 full seasons including several practices on it. I HAVE NEVER CHANGED THE VALVE SPRINGS. It turns 6450 rpms consistently. Is this an oddity or is it B.S. to change them every 3-5 nights. I was waiting on It to lose some power and change them but it kept getting better. Started out at 6200 rpms, i.proved car over time and now I'm at 6450. Am I playing with fire or is the chance ge them every month not needed. I do win races

You are probably on borrowed time. Get a on head valve spring checker and see where they are. I think guys were going 10 races on them and changing them, I'm not sure they even checked them just swapped them out.

The springs are much better then they use to be, also the newer style rev limiters do not "hit" as hard as the chip style rev limiters and are not as hard on the springs. But it sounds like you might not even be limited in the rpm you can run?
I can tell you a stock set of spring will turn 6600 rpm without floating the valves, but I dont recommend it.

A brand new spring will test at 80Lbs at installed height. Once you run them 1 night they loose almost 10 lbs of seat pressure. But after that initial pressure loss they dont seem to loose anymore pressure for a very long time. MOST racing sanctions allow up to a .020" valve spring shim to be used. I always run the shims to try and get back a little of that initial pressure loss.

With that said, you running them 40-50 nights isnt really giving up any rpm but it is hurting the valve and seat. That is why many of use still change them around 12-15 nights...it keeps the valve controlled and the seat in good condition.
If you were to do a leakdown test I bet you its leaking 10-15% past the valves. My crates with 30-40 nights on them (I dont keep them any longer then that) leak down at 3%, and thats going by the rings, nothing by the valves.

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Originally Posted by SRXSRULE

The springs are much better then they use to be, also the newer style rev limiters do not "hit" as hard as the chip style rev limiters and are not as hard on the springs. But it sounds like you might not even be limited in the rpm you can run? I can tell you a stock set of spring will turn 6600 rpm without floating the valves, but I dont recommend it. A brand new spring will test at 80Lbs at installed height. Once you run them 1 night they loose almost 10 lbs of seat pressure. But after that initial pressure loss they dont seem to loose anymore pressure for a very long time. MOST racing sanctions allow up to a .020" valve spring shim to be used. I always run the shims to try and get back a little of that initial pressure loss. With that said, you running them 40-50 nights isnt really giving up any rpm but it is hurting the valve and seat. That is why many of use still change them around 12-15 nights...it keeps the valve controlled and the seat in good condition. If you were to do a leakdown test I bet you its leaking 10-15% past the valves. My crates with 30-40 nights on them (I dont keep them any longer then that) leak down at 3%, and thats going by the rings, nothing by the valves.

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Thanks for all replies I appreciate y'alls input!