Valve spring pressure?
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Joined: Aug 2007
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From: Cambridge Ohio
Valve spring pressure?
I'm wanting to install new valve springs on my 87 with 128 heads. I'm putting 1.6 roller rockers in and the tech at Summit told me that thier brand valve springs @ 120 lbs. would work. The FSM shows closed pressure @ 76-84 lbs. I'm worried that the 120's are too much for my cam. Any suggestions on which spring kit to run with stock valves?
Le Mans Master
Joined: Aug 2010
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I just bought and installed a Com Cams complete kit /springs,1.6 rockers,pushrods, seals, sold by ecklers. I didnt want to have to guess and figured if they were putting their name on it, it they probably already knew it worked. It is exceptionally good, the same kit from Comp cams would have cost bout $100 more . with the newly rebuilt 3rd design injectors from FIC installed at the same time, my car is a pleasure to drive.
Safety Car
Joined: Apr 2005
Posts: 3,624
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From: Dale City VA
I'm wanting to install new valve springs on my 87 with 128 heads. I'm putting 1.6 roller rockers in and the tech at Summit told me that thier brand valve springs @ 120 lbs. would work. The FSM shows closed pressure @ 76-84 lbs. I'm worried that the 120's are too much for my cam. Any suggestions on which spring kit to run with stock valves?
The FSM recomendation/specs are for the stock cam and the stock rocker ratio.... Those recomendations go out the window when you modify things.
With a stock cam running 1.6 roller rockers, 120lbs seat pressure would be fine and not hurt anything.
You have a number of choices. You don't give a PN for the Summit spring but I am guessing it's a 1.250/1.265 OD spring orginally intended for limited class oval track racing. They work fine in hyd FT, mech FT and mild hyd roller applications like yours.
Howards Cams sells this similar spring that will work also for you.
http://www.competitionproducts.com/H...uctinfo/98212/
Here they are in a kit with all new CM retainers/locks (very good idea).
http://www.competitionproducts.com/C...ductinfo/VSA4/
The GM LT4 spring is yet another alternative that will work but have less pressure.
http://paceperformance.com/i-6255251...-diameter.html
Here are the required retainers for the LT4 Spring.
http://paceperformance.com/i-6255483...p-kit-lt4.html
Will
Last edited by rklessdriver; Feb 16, 2011 at 05:28 PM.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
Your 87 L98 should only have .431/.443 lift after the 1.6 rockers.
Good luck with your spring/rocker swap.
Will
