Valve Springs

[tbauer03]

Ok i went to the machine shop today and dropped off some parts and they didn't like my selection of valve springs. It wasn't something i gave much thought about and i need to do something about it. I figured i could use Comp Cams Conical Valve Springs 982-12 and have a good stock upgrade. But they said that they would not use something with 281lbs open and recommended some springs with at least 400lbs and they recommended springs designed for lt1's to take advantage of the roller cam, lifters, and rockers.
Basically i am running a comp 422 cam, comp 850 roller lifters, Crane 1.5 self aligning rockers. and i have a set of comp 7808 pushrods but i am probably going to need to get some stronger ones when i go to stiffer springs.
What Springs and pushrods should i buy?
Oh and they are going on to vortec heads.

Thank You in advance.

 

[bigtime]

I use 987 comps

 

[MikeRenz]

if you're using 1.5 rockers w/ your 422 cam you aren't going to need that beefy of a spring. I bet you could even get away w/ stock springs. I'm using 1.5 w/ a 412 came (practically the same) on 100% stock vortec heads.

until you step up to a 1.6 rocker, you aren't really taking that much advantage of the cam.

 

[ItsMyTy]

I'm using 1.5 w/ a 412 came (practically the same) on 100% stock vortec heads.
.

wow... didn't think vortec stock springs could take .500 lift

 

[bigtime]

Springs are cheap buy the ones comp tells you to and be done with it.

 

[MikeRenz]

yea springs are cheap. but at the same time, go with a tough spring and some high lift, and then you might need a hardened perch. I didn't want to risk that, and was sick of spending money on my ty's engine - thus stock springs/heads and 1.5 rockers. Originally i had 1.6's installed, but after some calculations i think we figured out that i would be getting like .580 lift (i think...it was a while ago and i didn't write it down) and that the stock springs would only be efficient to about .505-.510 at MOST.

And yes, according to whatever we looked up, the stock vortec head can handle .500 lift. I was more along for the ride as i watched the machine shop do the calc's and look up the different stats.

 

[bigtime]

perch?

 

[4C FED]

:flash:

 

[bigtime]

The seats are hardened, no worry there. Head valve seats have been getting induction hardened ever since lead went away

 

[4C FED]

:flash:

 

[tytom]

I would go and use tha conical springs from Comp. They will be fine with the .500 lift cam. Only one more thing to consider is with this relatively high lift cam and turbo boost trying to push them open You will probably get into valve float at around 6000rpm. However if You do not turn the engine this high then there is no need for stiffer springs. My understanding is that most people dont spin their motors faster then around 5500 in a SyTy so it never gets even near valve float.

 

[jwaller]

I used the comp conical LS1 spring in mine, seems to have worked fine for me.


comp has several springs for the LS1. get the ones for 600 lift.

 

[tbauer03]

I would go and use tha conical springs from Comp. They will be fine with the .500 lift cam. Only one more thing to consider is with this relatively high lift cam and turbo boost trying to push them open You will probably get into valve float at around 6000rpm. However if You do not turn the engine this high then there is no need for stiffer springs. My understanding is that most people dont spin their motors faster then around 5500 in a SyTy so it never gets even near valve float.

yeah this is what the machine shop guy was talking about and the reason he wanted to see something stiffer.

 

[tytom]

OK, but are You going to spin the motor over 5500-5700 ? If yes,then You may want some stiffer springs but only if they are really needed. You always
want to run the lightest possible spring You can get away with on a given motor combo. Stiffer spring=more frictional losses(even with a roller cam)=less power . I have those springs on another car (small block F-body) with a .510 lift cam and the engine is shifted at 6800. Valve float would come at around 7000. If You add boost say 20 psi pushing against the spring then effective seat pressure would be reduced accordingly. This is not a very significant reduction,only 20 psi x valve head area if I am not mistaken, so You will still be OK under 6000rpm. But heck, dont loose any sleep over this, if You feel better having stiffer springs in there then by all means go ahead and have them install whatever Comp Cams recommends for Your combo.