Stock valves installed height?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Stock valves installed height? (Sliding)
I don't know the stock installed height on my '88 L98 but can look up the seat pressure if you like; I believe it was around 85-90lbs seat pressure.
Remember that if you tossed the tin oil shedders from atop your stock springs you would need to shim the springs to even achieve stock installed height and so seat pressure.
If you installed 1.6:1 RRs, you will need a little more seat pressure as well as better springs. I installed my Comp Cams springs to give about 110lbs of seat pressure at 1.700".
Remember that if you tossed the tin oil shedders from atop your stock springs you would need to shim the springs to even achieve stock installed height and so seat pressure.
If you installed 1.6:1 RRs, you will need a little more seat pressure as well as better springs. I installed my Comp Cams springs to give about 110lbs of seat pressure at 1.700".
Racer
Joined: Oct 2002
Posts: 416
Likes: 2
From: Westfield MA
Re: Stock valves installed height? (Sliding)
Installed height per my 1987 factory shop manual is 1-23/32" INT, 1-19/32" EXH. Free length is listed at 2.03" (spring) and 1.86"(damper). Measure from the top of the shim or spring seat to the top of the oil shedder.
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
Re: Stock valves installed height? (SS409 425HP)
When I installed my springs ( larger that I ordered from LPE with 219 cam )
I just installed them without checking installed height. :bb :bb :bb
I asked LPE and they told me that inst. height should be 1.900".
I'm almost sure ( I'll take valve covers off and check one of these days )
that now my springs are too much pressed ( not enough height )
I made approx. 1000 miles since cam job and car runs great but I was about to install 1.6 RR's and now I'm affraid that I could break pushrod
or something if I do that because spring pressure will be even higher.
I'm really mad now. Looks like I'll have to take heads down again.
I just installed them without checking installed height. :bb :bb :bb
I asked LPE and they told me that inst. height should be 1.900".
I'm almost sure ( I'll take valve covers off and check one of these days )
that now my springs are too much pressed ( not enough height )
I made approx. 1000 miles since cam job and car runs great but I was about to install 1.6 RR's and now I'm affraid that I could break pushrod
or something if I do that because spring pressure will be even higher.
I'm really mad now. Looks like I'll have to take heads down again.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Stock valves installed height? (Sliding)
Well 1.90" sounds realy weak; are you sure about that number? Are they single springs with dampers or double springs?
When you install 1.6:1 RRs I think you want a little more seat pressure and that means less installed height.
In any case you don't need to pull the heads to adjust spring height; use compressed air or a rope to hold up the valve when you remove the spring. Have the piston at TDC as a safety measure to avoid dropping the valve into the cylinder.
When you install 1.6:1 RRs I think you want a little more seat pressure and that means less installed height.
In any case you don't need to pull the heads to adjust spring height; use compressed air or a rope to hold up the valve when you remove the spring. Have the piston at TDC as a safety measure to avoid dropping the valve into the cylinder.
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
Re: Stock valves installed height? (65Z01)
1.900" is what they gave me.
These are real double springs - 1.437" O.D.
But the problem is that I think I don't have enough space to get 1.900"
so heads have to be machined - spring seats have to go deeper.
These are real double springs - 1.437" O.D.
In any case you don't need to pull the heads to adjust spring height; use compressed air or a rope to hold up the valve when you remove the spring. Have the piston at TDC as a safety measure to avoid dropping the valve into the cylinder.
so heads have to be machined - spring seats have to go deeper.
Racer
Joined: Apr 2003
Posts: 260
Likes: 0
From: Palm Bay Fl
Re: Stock valves installed height? (Sliding)
I believe you can get different valve locks (keepers) that have the grooves lower to get you more room. But just be sure to check for Rocker arm clearance on the retainer if you do this.
-Dave C.
-Dave C.
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Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Stock valves installed height? (Dave C. '97 Z28)
Indeed Comp. Cams makes locks with +.050" installed height for both 11/32" & 3/8" valve stems but only with 10deg lock angle.
Anyway, the first job is to pull a valve cover and measure the installeld height of the springs.
If you know the seat pressure of the springs at 1.900" installed height and the spring constant, you can calculate current seat pressure.
Anyway, the first job is to pull a valve cover and measure the installeld height of the springs.
If you know the seat pressure of the springs at 1.900" installed height and the spring constant, you can calculate current seat pressure.