Cutting it close..

[nova10sec]

Well, I installed my new valve springs last night, and things were tight, here is what I had.

Originally I had an installed height of 1.88. That is with spring locators and mid point keepers. I bought a set of .050 up keepers which netted .025 up, and replaced the .065 locators with .030 hardened shims. The result, 1.94..

Now that sounds good until you factor in coil bind at 1.18, and the minumum clearance is .050. So 1.94-1.23 leaves 710 lift.

My new top secret cam is 737 gross with 1.6 rockers, net the lash out and it comes in at 717 on the intake side.

So it looks like she will be slightly kissing coil bind.....

[Real McCoy]

I usually go with plus .100 valve stems on cams with over 700 lift so that doesn't become a problem. Be sure to check your push rod length, and the retainer clearance to the guides too. You can cut the spring seats a little to get away from the coil bind if your pressure is OK at a greater height. What is the seat pressure of the springs at the height you need to use? RM

[nova10sec]

I am looking at 260lbs at 1.96, with .050 keepers and .030 shims (There aluminum heads) I only get 1.944 on 2 intake vlaves the rest are 1.95 + so there ok. The heads have never been cut, so I was trying to avoid it if possible.

I always run heavy seat pressure, feel more comfortable. I don't know if you check yours, but as soon as new springs are hit with hot oil, they usually loose 5-10% instantly.

[Real McCoy]

Everyone has opinions on spring pressures and not many agree on what is correct.......LOL. I run small rollers in all my BBCs and run 200 to 220 PSI on the seat. I check my springs frequently because the motor doesn't care if the pressure is 140 with a broken inner spring, it runs the same ETs and doesn't skip or even flutter. I see no real lose in pressure even late in the year when the motor has over 200 passes. The more radical the camshaft the more spring fatique becomes a problem in my experiences. Hope it all works out for you, RM