Thread: Installed Valve Spring Height?

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Originally Posted by roofcam

I'm replacing the valve springs as part of the cam change in my SBC. The installed height of the existing springs is 1.780", and the new spring installed height is 1.700". I could use shims, but how close do I need to be to the original 1.780? I have .015, .030, and .060 shims.

Thanks!

you want a -050 keeper less height if you now need to be 1.700 and were 1.780 so 080 less - NOT + keepers .if you go that way or a spring cup or hat works good to or you can get a retainer with less drop in the center a 060 and 030 would work but i like spring to locate at the spring seat in the head if you move it up with just shims the spring that much can when running move and cut the valve seal if you have room shims are ok but you want them to center on the valve guide to keep the shims from skiding side to side from lack of location of the shims . if it past the seat cup in the head use a cup or hat/spring locator and a 015 shim would work good .the ex side spring can break down from heat you can loose 10 lbs so shiming the springs 010 more on the spring will not hurt much it you use a .060and.030 and so would a 060 and a 015 would do to if not race on that stuff i shim to get the springs to read all the same you need a spring tester .for spring heigth set up i pull up the retainer up with keeper s on the valve stem with valve in head and use a 2inch snap /hole telescoping gage and set the gage were the spring would be and read it off a mic or vernier calipers or buy a mic height gage just for springs