Hi guys, what is the biggest, as in lbs, size valve springs you guys have used on a stock engine, stock heads, stock cam and have not wiped out a lobe? I here a lot of people wiping out lobes on cams and I think is has something to do with too high a valve spring pressure causing excessive stress on the lobe and wiping it out. Anyone have input, especially those that wiped out lobes, what valve spring pressure you guys use? Im thinking bout using the comp cams valve springs for the stock heads?
Valve Springs on stock heads?
- Thread starter my1stgn
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Comp 980's. I have HEARD the Comp 981's work well too! 90-105#'s.
Curious to hear what others will say
C
coach
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When I did mine, I used 980's. I think the only difference is whether or not you use the stock spring shields/cups over. If you use them, I think you want 981's. Most do the springs with the heads on the motor so 980's is most popular.
Thanks
Coach
Thanks
Coach
With a stock cam I would not use any thing bigger than 980's as it's asking to wipe lobes. Really I'd stick with 979's and use the stock cups. If you need bigger or concerned with valve float, step up to a roller cam BUT I've seen plenty of cars in the mid to high 10's running 979's or 980's, even unopened engines.
thadeal4real
Member
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- May 28, 2009
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new springs
trash the sheilds
trash the sheilds
trash the sheilds
If you run 979's you can not trash the cups, as they are needed keep the springs stable.
No, new retainers are not needed with 980's.
Why not? If you did get them with the set up would they still be fine to use. I'm getting ready to do mine and i have new 980's and retainers (7 degree that are recommended for the springs. i also got the comp valve seals to. A complete kit. Thanks
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- May 28, 2001
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- 2,527
Comp's bee hive springs for the LS1 motor work very well.
No more wiped cam lobes. Revs happily like never before.
No more wiped cam lobes. Revs happily like never before.
Or is it just a cost savings of $34.00 bucks. I really can't seeing not doing this only if it's too save a few bucks, when they too will have X amount of miles on them also. Just my .02 cents.
joe_schindler
Living better with carbon
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What does the chain have to do with the lobes?
I'd guess that more lobes are wiped from cheap or dirty oil rather than the springs. But; if you're using better than stock springs; why would you not use a better than stock cam and lifter?
Better than stock in what way? Ive seen stock cams go 300k and at least 100k of it was on springs that were 90-100psi on the seat. Those are proven. The best hydraulic flat lifters you can get are the ones GM used in the LC2 at the factory. At the time there were 3 manufacturers of lifters for the 90* v6. Not sure who made them for GM but they sure stand the test of time with the proper oil. The oils of late are garbage for a flat cam unless a zinc additive is used. BG supplement with zinc or ZDDPlus have it covered. If you want a better than stock setup plan on a roller. As far s performance goes if you have stock untouched heads you will gain nothing with more cam unless you are running it really hard and trapping over 120mph.
turbo nasty
Turbo Dojo / MNTR
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979's here for right at 10 years w/ stock cam. She'll still rev to 6 k if i want. found out when I had the wrong governor in teh trans
It shifts a lil north of 5200 now.
6 of the springs came with a inner dampner it was removed, dont remember if I reused the cups or not my guy says yes but not 100% and new hardened speedpro locks from advance parts.
It shifts a lil north of 5200 now.
6 of the springs came with a inner dampner it was removed, dont remember if I reused the cups or not my guy says yes but not 100% and new hardened speedpro locks from advance parts.
joe_schindler
Living better with carbon
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- Messages
- 842
I’ve seen some pretty high (200 – 300 M) mileage engines also. Some of them might not have had 100 PSI open pressures. If you’ve got a high-mile engine (or you probably wouldn’t be changing springs); it’s probably got some wear on the cam that will be amplified by the higher spring pressures. The low spring pressures are probably the only thing saving the cam lobes.
I agree. Proven; and working as a package.
I think it was Johnson. I don’t know if you can get the same (manufactured the same way) lifter anymore.
I agree. And; most high-mile engines have had some lack of maintenance along the way; including poor oil-change habits. As long as the spring pressures are low; the cam will work fine. But; push the lifter a little harder on to the lobe for a while; and the lobe seems to disappear.
Roller is the way to go. Even on a low performance engine; the factories have seen that there is a reduction in friction that will increase gas mileage and lengthen cam and lifter life (cuts down on warranty work). For an unported stock head engine; you won’t be able to get all the benefits that a roller cam setup can deliver; but not having to change a cam just once will usually pay for the difference in price. It surely will if you’re paying for the labor.
On the seat spring pressure
The stock cam drawing shows an on the seat spring pressure of 80 psi with a +/-2.5 psi tolerance.Gm Powertrain thought 82.5 psi was what on the seat spring pressure needed to be.Also since the stock valve seats are not hardened we accelerate pound out by craziness with valve springs,not to mention the wonderful airflow characteristics we now gain with our ported heads and pounded seats.
The stock cam drawing shows an on the seat spring pressure of 80 psi with a +/-2.5 psi tolerance.Gm Powertrain thought 82.5 psi was what on the seat spring pressure needed to be.Also since the stock valve seats are not hardened we accelerate pound out by craziness with valve springs,not to mention the wonderful airflow characteristics we now gain with our ported heads and pounded seats.
