The Stovebolt Site Forums The Shop Area Engine Shop 235 valve spring force

Has anyone here measured the pressure on their old valve springs?
Before I ripped off my cracked cylinder head the engine actually ran pretty good. It's valve springs exert about 54 pounds (just below the minimum 235 spec) when compressed to the 1.844" test length (see page 8.8 of the manual).

My replacement springs test ~83lbf (wayy to high for a 235, but pretty close for a 261) and now I'm having a hard time deciding which spring to run.

I like the idea of the soft old springs being gentle on my cam, although I am planning to upgrade to a 261 cam... I'm speculating that the stiffer spec for the 261 might have been chosen because those trucks originally had such low gears that the engine would spin fast more often. Since I have tall gears I'm thinking I could get away with the soft springs?

Use the heavier springs. Neither one is particularly extreme- - - - -I'm accustomed to running triple spring setups with 300+ pounds of seat pressure on round track race engines. If you ever happen to get into an over-rev situation and float some valves the soft springs might allow some valve/piston contact and bend a few valves. That soft spring pressure might not seal the valves properly under compression, also.
Jerry

Thanks for the tips hotrod... you're on a roll lately!
83lb doesn't seem so stiff now that you mention those other springs.

The soft spring might work ok on the smaller exhausts but with the bigger intake valve's mass and any kind of rpm above 3000-3500 might not be enough to seat it, without float

I just had a head rebuilt and used 110 lb springs