L98 Valve seat load??
Thread Starter
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I am installin Comp Cams valve springs #981. They are rated at 110lbs @1.7" installed height w/ a rate of 400lb/in.
My installed height is now 1.78"; I can easily shim it to 1.75" for a seat pressure of about 90lb. With a lift of about .445" at the spring the open pressure will be about 270lb.
I was basing my spring selection on TPIS #700-132 which is rated at 105lb @1.8" with a rate of 400lb/in. TIPS says that 90-110lb seat pressure is OK.
I don't want excessive pressure but also don't want disasterous valve float.
Is my install pressure going to be sufficient or do I need to shim my install height to 1.7" to get the 110lb install pressure?
My installed height is now 1.78"; I can easily shim it to 1.75" for a seat pressure of about 90lb. With a lift of about .445" at the spring the open pressure will be about 270lb.
I was basing my spring selection on TPIS #700-132 which is rated at 105lb @1.8" with a rate of 400lb/in. TIPS says that 90-110lb seat pressure is OK.
I don't want excessive pressure but also don't want disasterous valve float.
Is my install pressure going to be sufficient or do I need to shim my install height to 1.7" to get the 110lb install pressure?
Thread Starter
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I just found the stock specs:
76- 84lb @1.70" - closed
194-202lb @1.25" - open
So I can safely install the CompCams springs with the Ti retainers at 1.78" to get 78lbs.
If I install the .030" oil shedders under the retainers I'll be down to 1.75" with 90lb.
Or .060" shims under the springs give 1.72" at 102lb.
Thanks for feedback, gotta make a choice and order more parts tomorrow am.
76- 84lb @1.70" - closed
194-202lb @1.25" - open
So I can safely install the CompCams springs with the Ti retainers at 1.78" to get 78lbs.
If I install the .030" oil shedders under the retainers I'll be down to 1.75" with 90lb.
Or .060" shims under the springs give 1.72" at 102lb.
Thanks for feedback, gotta make a choice and order more parts tomorrow am.
