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Old 11-20-2007, 09:40 PM
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Valve Springs - Installed Height - Does it have to be Exact?


I'm about to order new valve springs and possibly shims and stuff. The manufacturer specifies an installed height of 1.900" for my comp cams 924 dual valve springs on my BBC iron heads. It's for a Hyd FT cam. I just took measurements with the valves and retainers I have. The average measurement was 1.860. That is .040" less than the mfr specifies. My question is: is that going to be a problem for me or is it ok to be a bit less installed height?

the cam has a .578" lift, so if I make sure there will be no coil bind is it ok to use those springs - or should I be getting new retainers and/or valves? I'd like to use what I got and avoid spending more money if you think I'm ok.

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Old 11-21-2007, 07:35 AM
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Originally Posted by F-BIRD'88
The comp 924 spring is rated @1.88" installed height (125LBS) If you install at 1.86" or more you'll be good to go. Installed seat pressure will be around 130lbs. If your lowest installed height is too low you can buy +.050" valve locks to adjust the installed height. If one is just a little too low try different retainers and lock pairs. There is some variance.
Dear F-bird:

your response make sense. but check the latest comp cams published specs on the 924's. they say the installed height is to be 1.900, NOT 1.88". also I didnt know that you can buy spring retainers with +/- .050" height change. that will fix my problem. Only thing is, I just checked one of my retainer/valve/lock assemblies. If I get the +.050" locks, the retainer will be placed higher on the valve stem, flush with the top of the valve stem. Typically the top of the stem is a bit higher than the retainer to the rocker won't contact it. I think this will be ok though because I have roller rockers and it does not appear the roller rocker will contact the top surface of the retainer. Do you understand?

If I get the +.050" locks and shim the spring pocket .015" that should put me almost exactly at 1.900 installed height as comp cams suggests. Only downside like I said is the spring retainer gets moved up higher near the top of the valve stem.

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