Valve Spring Shimming Question
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On The Tree
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Valve Spring Shimming Question I have a set of Comp 918's and a MTI B1(221/221-.558/.558-114) cam to install into my Camaro and I'm looking for some info on how I should shim the springs.
The springs and cam are used(about 3000 miles) so I'll be taking them to a shop to be checked for spring pressure, but what I need to know is should I shim them so they are 50 thou from coil bind at max lift?
The springs and cam are used(about 3000 miles) so I'll be taking them to a shop to be checked for spring pressure, but what I need to know is should I shim them so they are 50 thou from coil bind at max lift?
Pretty sure 50 thou is just the spec as in it shouldnt be any tighter than 50 thou. at max lift...any looser is fine....
This is my understanding of shimming springs........
If the installed height is say 1.8 and supposed to have 200 spring pressure (just an ex.) but your springs only have 180 then you can put in a certain thickness shim to get it back up to 200 rather than getting new springs.....so basically when you cut the valves or seats that raises the valve retainer up more meaning less spring pressure on the seat you need to shim them or if you just want to use some springs that are a little worn out and want to get them back within spec you can shim them.....
Someone correct me if I'm wrong.
This is my understanding of shimming springs........
If the installed height is say 1.8 and supposed to have 200 spring pressure (just an ex.) but your springs only have 180 then you can put in a certain thickness shim to get it back up to 200 rather than getting new springs.....so basically when you cut the valves or seats that raises the valve retainer up more meaning less spring pressure on the seat you need to shim them or if you just want to use some springs that are a little worn out and want to get them back within spec you can shim them.....
Someone correct me if I'm wrong.
Thread Starter
On The Tree
Joined: Nov 2006
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Well I think I should have some room to work with them as they are a .600 lift spring and I'll have a .558 lift cam.
I think I'll install them to there installed height spec and just run it for a year like that. Unless a shop can test the spring pressure at certian heights of compression so I can determine what height I need to install each spring to get a certian seat pressure.....that would help...not sure if it would make much more power.
If I'm way out to lunch on my thinking here and I should simply swap the springs and run it, would somone please let me know. I'm just trying to gather as much info as I can b4 I take it apart.
I think I'll install them to there installed height spec and just run it for a year like that. Unless a shop can test the spring pressure at certian heights of compression so I can determine what height I need to install each spring to get a certian seat pressure.....that would help...not sure if it would make much more power.
If I'm way out to lunch on my thinking here and I should simply swap the springs and run it, would somone please let me know. I'm just trying to gather as much info as I can b4 I take it apart.
Originally Posted by BAMF
Unless a shop can test the spring pressure at certian heights of compression so I can determine what height I need to install each spring to get a certian seat pressure.....
If you measure, you will likely also find out the stock setup is less than 1.800". Mine were 1.760" or there about. Not sure why everyone keeps quoting the 1.8" number as it is just a spring specification.
