Comp 987 dual valve springs?
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TECH Regular
Joined: Mar 2003
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From: W.P.B
Comp 987 dual valve springs? I currently using Comp 987 doubles in my H/C car. With the new comp doubles out, and other company's that came out with "NEW AND IMPROVED" valve springs, are my comp 987's still a "GOOD" spring of choice? 
The general concensus I get from most shops is that the 987 isn't a very good spring. I have them on my car right now and i'm getting a pretty big dip @ 6K which is I believe is from the springs. They've also been known to fatigue very quick when running a bigger fast ramp cam. I wouldn't recommend them again considering what I have learned from some other LS1 shop owners. I will be taking them off my car soon...
josh
josh
Originally Posted by phenyxTA
Which springs does he usually use? My Absolute heads came with dual springs and I have no idea what brand they are.
It depends on what cam you use too. I have a G5X2 cam and the springs cant handle the ramps of that cam. If you have a TR cam or the like, they should work just fine
What Josh and Country boy said. On the slower less radical ramps the 987's are ok. Most folks(that I know of)that are running fast/stout sticks are moving over to the 977 for the higher pressure values.
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TECH Junkie
Joined: Jan 2002
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From: At the office
Originally Posted by Country Boy
It depends on what cam you use too. I have a G5X2 cam and the springs cant handle the ramps of that cam. If you have a TR cam or the like, they should work just fine
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Brett Foote
Launching!
Joined: Mar 2003
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From: Oceanside CA
Originally Posted by Country Boy
They dont seem to be up to the task. Jay @ Absolute is changing out my 987s for some 977s, but you will need the Comp R lifters.
Originally Posted by Scott Turvey
Why the need for the Comp R's? I'm still trying to figure out what the real difference is... In the 2004 catalog, Comp only lists one lifter for the Gen III.
Its due to the spring pressures. They will collapse a stock lifter per Comp.
Also, the LS1 uses the same lifter as a SBC
At a quick glance, I found 2. Look up part # 875-16 under the Pro Magnum Hydrolic lifters. Theres also 850-16 under the High Energy Hydrolic
At a quick glance, I found 2. Look up part # 875-16 under the Pro Magnum Hydrolic lifters. Theres also 850-16 under the High Energy Hydrolic
Originally Posted by Hardtop
My 987's are holding up fine with a TR230/224. Peak power at 6450, only loosing 7 rwhp at 6800. Graph is real smooth, I seriously doubt that I have valve float issues.
Bruce
Bruce
Originally Posted by Country Boy
Verbs means with the YT rockers too, unless you have them. Some have had problems with valve float. When your at or near the edge of what a spring can do and you slap on a set of rockers with more mass (weight) on the valve, the spring has to work more to make up for the added weight and it cant keep up, so they start floating.
Bruce
Launching!
Joined: Mar 2003
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From: Oceanside CA
Originally Posted by Country Boy
Its due to the spring pressures. They will collapse a stock lifter per Comp.
I looked at the other lifter you talked about in your next post, and I'm going to call them. It's one of those things you just don't bother with, but it's bugging me now. I mean, "designed to perform at higher engine speeds... when the lifter inevitably pumps up" (Pro Magnum lifter) and "designed for Craftsman Truck and Busch Grand national applications" (Gen III lifter) doesn't really explain it to me.
I'll post after I talk to Dave (Comp)
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From: Arlington, TX Congestion City
There is no way you can expect the 987's to hold up to the G5x2 cam. They are maxed on my setup with .588 lift. i don't ahve any valve float luckily. But I am pushing the limit on mine. I will more than likely switch in about 10k miles or when I notice valve float to either the new 977's or the Crane duals. On a side note it is not a matter of just swithcing out the spring. You need a different valve in order to run the 977's in the AS heads.
I know COMP says that the stock lifters are not up to the task with some of these higher rate springs but I HAVE NOT seen any issues just staying with the stock lifters even using ISKY's dual spring.
Originally Posted by 94form2000z
There is no way you can expect the 987's to hold up to the G5x2 cam. They are maxed on my setup with .588 lift. i don't ahve any valve float luckily. But I am pushing the limit on mine. I will more than likely switch in about 10k miles or when I notice valve float to either the new 977's or the Crane duals. On a side note it is not a matter of just swithcing out the spring. You need a different valve in order to run the 977's in the AS heads.
Also, as far as lifters go, I ran my 987's and had no problems with my cam in sig. I did eventually go with 978's and with the STOCK 70K mile lifters went 9's, so no problems there, 400 lbs open pressure, now have Comp R's when I did the last head swap.