Pictures - up pipe and valve spring cups

[mblum]

Yes, those shims will work with the stock cylinder heads.

1.250" OD X .814" ID X what ever thickness you decide to use.

 

[Fikse7]

I did Comp 980 springs without cups and I used shims that brought them to 1.697" seated. Your shooting for 1.7" so you can get the spring pressure up to its listed seat pressure of 92 at 1.7". Can't remember exactly but I wanna say I used .030 shims under the springs or else the springs are 1.667" installed by themselves and the pressure is way lower than rated. I think it drops down to the like 84psi at 1.667" rather than 92 pounds seated pressure at 1.7". Its best to buy a set for 8 cylinders and have a shop pressure match a 6 cylinder set for you. That is all I can say to that.

Joe,

Trying to understand this in my simple mind, but wouldn't the height be greater without the shims? Without the .030 shims, it would be 1.697 + .030 = 1.727??
Am I understanding this correctly? Also, using shims for reduced installed height = more seat pressure?

 

[pacecarta]

no it will be shorter , installed spring height decreases with the shim
with 030 the 1.697 will now be 1.667 and spring pressure will increase because you've raised the floor squeezing the spring
shimming also changes (reduces) the amount of travel the spring has before bind . should not be an issue with stock cam lift

 

[Fikse7]

no it will be shorter , installed spring height decreases with the shim
with 030 the 1.697 will now be 1.667 and spring pressure will increase because you've raised the floor squeezing the spring
shimming also changes (reduces) the amount of travel the spring has before bind . should not be an issue with stock cam lift

Got it - thank you

I've ordered the CC shims so I can install each spring at 1.70 height. Assume shims are placed directly on top on the head, nothing extra required to keep them in place?