Other then having the needed minimum retainer to seal, or retainer to guide clearance the installed height is all about the spring.
The installed height needs to provide the minimum seat pressure as stated on the cam card while NOT having the installed height such that the spring is at coil bind.
On most duel spring set ups I have used for a non roller hydro cams in motors that can buzz to 6000 rpm, the use of a .030 shim will add 10 psi to the seat pressure.
When setting up the installed height with new springs I almost aways add a .030 shim just to compensate pressure loss once the spring breaks in.
If its for a small valve head 1.96/ 1.66 and I already have the 125 seat pressure I like to start off with and if I know the motor will not need to go above 5800 then I might leave out the .030 shim.
This applies to a true duel spring set up.
If due to the customers choice I am using a set up that is only a outer spring and a flat wire damper, the. I do add the .030 shim.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
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