Hardtop

iTrader: (3)

I have TEA heads with 987's on them, and have never had any valve float. Ran the motor to 6750 rpm on the dyno, and shift at 6600 rpm at the track with no problems. I'd rather have them instead of 918's if I broke a spring.

Bruce

TEA Brent

The actual coil bind on the Comp 987's is around 1.090" or so. We check each set we install and put the actual installed height (around 1.770-1.780) with the corresponding seat pressure (around 140-150 lbs) and the actual installed height, because there are suttle differences in valve length, retainer height, lock height, spring pocket height, etc. We SHIM every spring to the same height, that should go without saying. We have seen one set of LS1 heads that were run for a year with an average lift cam of around .570" that the 987 springs were killed in. There are some cam lobes for the LS1's that were developed with a 1.5 or 1.6 rocker so the cam designers were computing max acceleration based on that. Those lobes were then ground on LS1 cams that use 1.7 ratio rockers and there is simply too much acceleration for the springs to handle long term, and they give out.

Phillip, we have some different springs that set up at the same installed height but are about 40 lbs more open, or roughly 400 open, which is the max I would run. Let us know if we can help.

Thanks, Brian at TEA

needmoremoney

So are you saying 987's aren't good springs? if so, what do you recommend?

Phil99vette

iTrader: (11)

Let me clarify some things about my inital post a couple of days ago. My old setup with the TEA heads, 987 springs, and 230 XE cam ran flawless. Last time I was at the track the car went 11.3 @ 124 with no signs of valve float. Once I built my new engine I switched to an XER cam and yella terra rockers(1.7). Since I have changed to the XER cam and TY rockers my car's power falls over 6300 RPM which makes me *think* that its valve float. ***Note this did not happen with the XE cam and .570 lift(car pulled to 6800 on the dyno). Who knows maybe the faster ramps need heavier springs, maybe I have a broke spring.

The thing that made me look at the springs was a friend suggested that my power falling off may be caused by valve float and after reading the Comp Catalog and seeing that the 918s had a Recommended Max lift of .600, while the 987s had a Recommended Max Lift of .500 made me start to question if the valve springs were the problem. Now I am no spring guru but IMO the seat pressures and coil bind #'s would make you think that the 987s are good to .600+ lift. I am very pleased with the Comp 987 springs but something is causing my valve float.

Now a big issue when you go to a larger lift and duration cam is going to be springs with more seat pressure. At what point does excessive seat pressure start to collapse the lifter?

One last issue that needs to be addressed is that I am not trying to bash Total Engine Airflow by any means, I have been very happy with their heads from day one. Anytime you can take a H & C car with a 100 shot and go 134mph in the traps has got to make you smile.
Phillip

BLUEBYU

iTrader: (1)

I was hoping Mark at Raging would post up....he just went through this valve float problem with the 987's. He is running close to a .620 lift though He simply upgraded the inner damper and all is good.

383ss

iTrader: (14)

I'm running .602 lift and was told 985's would be better than 987's to go with by my head porter.... thought mark at RMS was doing the same/???

TEA Brent

I am not saying that the 987 is no good, because it is an excellent spring for $75-$80. Just like Phillip said his previous cam went 6800 on the dyno flawlessly, so does my car, so do most peoples cars. However, it is not the ultimate spring, there are better springs but they cost almost twice as much money! So for me it is always about bang for the buck. If it will get the job done then why mess with it? I don't want to charge 100 people twice as much for springs that will not benefit them. As for Phillip he has obviously crossed the threshold of what a 987 is good for.
Phillip, to answer your question Comp has a 978 that will probably do the job, as far as how much pressure a stock lifter can hold, I don't exactly know for a LS1, but the blue oval stuff we have set up as high as 180 seat and 400 open, and with a soft ramp cam is good to 8000 RPM on our dyno. The thing that destroys RPM ability as much as anything is lift, we have 306 cu in Ford stuff that goes 10.30 @ 130 on motor with .500" lift cams. The engine will turn 8000 RPM with no problem. Our power adder 306 Ford stuff has run 8.60 @ 160 MPH with .550" lift hyd roller and factory unmodified lifters! That was done with a TFS Twisted Wedge street head and a street Holley SysteMax intake (that I helped design when I worked at Holley in 1994-95) So you guys that are running more then .600" lift or running too much ramp speed are shooting yourself in the foot IMHO, unless it is a strip car only and you are willing to deal with valve spring maintenance. I hope this helps!

Thank you, Brian Tooley @ TEA

1999_SS_M6

I agree with Brian's above post.. This thread is headed in the same direction of those annoying "which cam is best" threads. There is no "best" cam, only "best for your application."

We're about to start the same kind of rampage over valve springs. There is no "best" valve spring, only "best for your application."

Worried about valve-float? increase spring pressure. (and collapse your lifters)

Worried about collapsing your lifters? go solid roller.

Yada yada yada. It goes on and on. You just have to understand that unless you're going through the whole motor, pick the best bang for the buck components for the HP level you want, the RPM range you're running in, and with respect to to amount of driveability and reliability you want to retain.

Smoke_ur_5.0

iTrader: (2)

It probably valve float. The Yella Terra's are giving you more lift at higher RPM's since your stock rockers flex. You have a couple of options. Switch back to stock rockers or..switch the inner spring over to what the 985's use. (Outer springs on the Comp 987 and 985 are the same) If it's not a big deal for a few extra bucks just buy new 985's for $89 and switch them all out. This would be your cheapest and easiest fix for now. You want to go with the least amount of pressure that still gets the job done.

We ran .612 lift on our car and had the same issue.

383ss

iTrader: (14)

thanks mark... saved me a phone call. I'll be ordering 985's tomorrow.