Summit Racing STG 2 (shim advice)
Thread Starter
Joined: May 2011
Posts: 8,485
Likes: 1,032
From: Wichita, KS
Summit Racing STG 2 (shim advice) Currently running your STG2 summit turbo grind. SUM-8706 in a 4.8. Running it with BTR .660 lift dual springs. Car seems to nose over pretty hard at 7200. I believe this may be due to me using a .660 lift spring on a .600/.575 lift cam.
Would you suggest putting a .060 shim under the springs? I'm aware I'll need to check them. But I haven't ordered parts yet and don't have it apart. I'll double check b4 install. Just wanting a ball park to order shims.
Valve Spring specs are as follows: •155 lbs @ 1.780" •380 lbs @ 1.180" •400 lbs @ 1.130 •Coil bind @ 1.070"
Thanks
Would you suggest putting a .060 shim under the springs? I'm aware I'll need to check them. But I haven't ordered parts yet and don't have it apart. I'll double check b4 install. Just wanting a ball park to order shims.
Valve Spring specs are as follows: •155 lbs @ 1.780" •380 lbs @ 1.180" •400 lbs @ 1.130 •Coil bind @ 1.070"
Thanks
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Joined: Jan 2008
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From: Ohio, Georgia, Nevada, Texas
Adding shims would be helpful and could add a little more RPM. .060" shims would be a pretty safe bet since your springs are rated for .660" lift. With the 377 lb. spring rate, the seat pressure would go from 155 lbs. + 22 to 177 lbs. Another thing you could do is our 11/32 HDR pushrods.
Lastly, you could run short travel lifters or run more preload on your present lifters. The oil aerates and bleeds down which causes a loss of lift at the valve. .070" is our recommendation for LS7 lifters which are close to .165" travel.
Lastly, you could run short travel lifters or run more preload on your present lifters. The oil aerates and bleeds down which causes a loss of lift at the valve. .070" is our recommendation for LS7 lifters which are close to .165" travel.
Adding shims would be helpful and could add a little more RPM. .060" shims would be a pretty safe bet since your springs are rated for .660" lift. With the 377 lb. spring rate, the seat pressure would go from 155 lbs. + 22 to 177 lbs. Another thing you could do is our 11/32 HDR pushrods.
Lastly, you could run short travel lifters or run more preload on your present lifters. The oil aerates and bleeds down which causes a loss of lift at the valve. .070" is our recommendation for LS7 lifters which are close to .165" travel.
Lastly, you could run short travel lifters or run more preload on your present lifters. The oil aerates and bleeds down which causes a loss of lift at the valve. .070" is our recommendation for LS7 lifters which are close to .165" travel.
