What lift are they good too? I was told .630, as I hope the person that told me that is correct.

 

also, here is a link to comp cams website page that shows detailed info. Just look at the very left of the screen, and look down till you see 987's. http://www.compcams.com/catalog/303.html

 

If you look at the catalog where they list springs by spring height you will find recommended lifts. I believe that the 987s have a recommended lift of .500 and it just so happens I was on the phone with one of the best names in LS1 heads and they did not recommend 987s.
Phillip

 

http://www.compcams.com/catalog/306_307.html

If you look at that page it says rec max lift .500"
Phillip

 

Yes, I see what your saying. I think I have a problem here. I paid more to have 987 installed, becuase my cam is pretty big, that 918's wouldn't hold. Now, my 987 have an inner spring aswell, and then a dampner in the dead center. Why was I told that these springs are good up to .630 lift?

 

I'm not sure how to get the correct specs for the LS1 but that info at max lift being .500 is probably with another rocker ratio or something I'm sure. The 987 is a stiffer spring than the 918 and can handle more lift. Why would TEA put these springs on their heads if they only can live up to .500 lift?! You'd only be able to run a stockish sized cam if that was the max lift! That isn't right. There are plenty of people running big cams on these springs and I haven't heard of any breakage occurances. Maybe someone with more info or knowledge will chime in. I have been told they will take .630 lift on the LS1 as well.

 

Here is a quote from an ls1.com user. I found this using the search feature:
"I have the X1 on a 109 and im using Comp 918's on a stalled auto Im putting the G5X2 in with stage 2 6.0L heads with Comp 987 Dual springs and 9.5:1 CR, the ATI D1 at 12lbs will go on a month later."

If these springs were only good upto .500, then why are more than 50% of us people doing aftermarket heads, and cams using these springs? Am I missing something here?

 

lol... if 987s were only good for .500 lift you'd be reading alot of posts about broken valve springs I've never seen a post about a broken 987....

I'm not exactly sure how to interpret the info on comps page... but I don't think it means .500" lift is the max it can handle...

 

When I talked to GTP they said that they would not recommend these springs for any of their LS1 heads.
Phillip

 

Thats what im saying, comp 987 springs are some of the best springs for high lift cam in LS1's and for PHIL99VETTE, Im not trying to argue with you, or to **** you off, but who ever told you 987's weren't a good spring, doesn't know what there talking about. All I can say about the person who told you this is .

 

well, then what springs does GTP use? REV's? I would still use my Comp's over the REV's, but don't ask me why.

 

I have the Lunati Double REV springs in my car...so far, they have been great!

..a real PITA to install, however....

Hey needmoredough:

..when are you gona build that orin stroker?

 

Im no spring expert...so im just throwing this out there. But According to the Chart..at an installed hieght of 1.80 you will have a spring seat pressure of 121 lb. And an open pressure at 1.20 of 328 lbs. If those spring loads are enough for your cam you could have at least .600 lif available. It also sias coil bind is at 1.150. So leaving say .020 of room before coil bind (not sure what recommended limits are) you could have a potential of .630 lift. Hopefully Im close in my description.

 

Here is a good thread, on of all places Corvetteforum covering this.

http://forums.corvetteforum.com/zerothread?id=598703

'97 C5
Senior Member


181 posts [100%]
Santa Clarita Ca

Re: Comp 987 springs only good to .500 lift on Comp's.... (Phil97SVT) 6:03 PM 7/6/2003


THe 987's can be used with more lift, depending on installed height, but will not yeild great pressure numbers when set-up for a cam beyond .500 lift.
I changed to Crane #99893 - these springs set up with 150# seat and 425# open and with a .615 lift cam still have .085 to bind.

I urge you to speak with Richard at West Coast Cylinder Heads - http://West Coast Cylinder Heads

[Modified by '97 C5, 3:03 PM 7/6/2003]


Walt Donovan
Senior Member


270 posts [100%]
Tinton Falls, NJ usa

Re: Comp 987 springs only good to .500 lift on Comp's.... ('97 C5) 9:02 AM 7/7/2003


Read what '97 C5 wrote. This is the very first inkling of an understanding of valve springs I've ever read on this forum. Springs aren't made for a specific lift (or cam or rocker ratio) but..... When you add more lift you do two things to tax the ability of the spring to control the system. 1) You increase acceleration in the same proportion that you increase lift, and 2) you must set up the spring taller to account for the extra lift. Doing this naturally decreases the seat pressure.
You have one saving grace in that most spring manufacturers have their heads up their .... (well nevermind). Anyway, the spring makers mostly claim their springs should be set up at least .075 from coilbind. They are slowly pulling their heads out though. They used to cringe if you set up their springs less than .100 from coilbind. Have the laws of physics changed so that springs can be set tighter? Remember this, the further the open lift spring is from coilbind, the lighter the force over the nose, the more chance to slam the coils together. I set circle track springs at .035 from CB, prostock at .050 from CB. The only reason the PS springs need so much room is that these heavy triples get very tight just before CB and put extreme loads on prods.

If you get numbers on your springs you can estimate what difference shimming would make. Take the mfrs numbers of installed ht, seat pressure, rate, and distance from CB. If a given spring is 120# @ .085 from CB and you want to squish it to .035, you are adding .050 shim. This .050 times a rate of 344# per inch is 12#. Add this to the 120# seat and you see 132# on the seat. Same thing for adding lift while maintaining distance from CB. Add .050 to your installed ht DECREASES seat pressure by 12#. Anyway, all this means nothing unless you know what shims are and where to put them. In a year or so on this forum, I've NEVER seen a mention of spring shims.

Anyway

 

J-Rod,

That certainly was an informative post, but the only answer I get out of the question "what lift is this spring good to" is that it depends on the height it's installed at..... what I want to know is what lift would this spring be good to (with *acceptable* pressure/safety from CB) installed as-is with no spring shims on an LS1? Anyone know?

If anything over .500 lift gives inadequate spring pressures why are so many shops using them then? Almost every aftermarket LS1 cam I've seen is way over that and more commonly around .600 lift.

 

[quote]
I was the one to first post about this question so I am not taking it like your trying to argue. Craig Gallant from GTP was the one that said he would not recommend the 987s. As far as him knowing anything, I think this track record speaks for itself. My question came up because I am experiencing valve float above 6400 with the 987s.
Phillip

 

Phillip,
What spring's are you using now?...or what did craig reccomend?The 987's have a max lift of .600" lift...but with a cam of .580" or larger (but still below .600") will get valve float without a doubt...mine is only .568"/.573" and i get valve float like crazy above 6k with my 987's..I think the 987's are a great spring..but only for cams with less than .560" or so lift...just my honest opinion though T.E.A does an excelent job with their head's...but i sure as hell am getting valve float above 6k..iv'e even had it start at 5800 before and have to get out of the throttle cuz im scared of kissing a piston or breaking a spring....What spring's should I get

 

can't be .500 lift.....0.600" perhaps....

why?

because I'm running them NOW (have been for the past 7 months with a TR224/224 with 0.563" lift and lots of spins to 7,000RPM. When I was setting up my heads, TR told me that the 987s were good to at least 0.600" depending on how you set them up (install height).

 

Do you have any idea of the volume of heads TEA is putting on the road? They install 987's on their product, and I've never heard even once of a failure. Also, like you said NEEDMOREMONEY, Brent at TEA told me the springs were safe to .630 lift.

The 987 springs were recommended to me to run with my .224/.224 .581 lift camshaft. My spec sheet they sent with my heads says:

130# @ 1.800
325# @ 1.250
coil-bind @ 1.150

Do the math... 1.800 - 1.150 = .650

 

Gosh, I just wish I knew exactly what my "installed height" is, so I can know what lift my 987's are good up too.