I have heard that there is power to be made by shimming rocker arms, can some one explain on this or tell me where to find info on how to do this.
I just installed heads/cam. Comp Cam 231/237 .589/.595 112 lsa,patriot heads ls6 59cc. chrome molly p-rods, 850 Comp Cam lifters. I get that sewing machine sound and have noticed by pushing down or pulling up there is some play. will shimming help this or should I get longer p-rods? either way I go, how do I measure for shims or correct length p-rods? any help on this ,I would appreciate. thanks

cowboysfan

 

Shims are gonna change the contact point of the rocker to the valve. Pushrods length is probably what you're gonna be concerned with. JRP's FAQ page has a p/r calc link on it.

I gotta do the same with mine. I'm about to order a p/r checker.

 

so if I shim my rockers, I'll have to check p/r length? who/what is JRP ?


fuerzaws6
formerly (cowboysfan)

 

The JRP cam guide is what he is refering to, its a stick at the top of the internal engine section. https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html

 

Sounds to me that the idea here is that by shimming the pedestal, the rocker hits the valvestem closer to the tip, effectively increasing the rocker ratio. For the 1 or 2 HP i could see this making, it dosnt seem to be worth having incorrect geometry and inproper lifter preload.

 

I had the same problem a week ago when I installed my cam. I changed to 7.425 PR's and now it is much quieter.

 

Longer p-rod is your answer
7.425's will help a lot

 

cool thanks. I did the geometry align. check. did look centered but, .025 is hard to see.

greatwhitess- what lifters are u currently using?

I'll order some p-rods (7.425) soon.

thanks guys.

fuerzaws6