layjzay

Looking to replace my valve springs with dual springs. Hearing about too many of the single stock springs breaking. I'v contacted several of the forum vendors but they are selling a comp 921 spring with a install height of 1.770 according to comp web site and the LS7 install height is 1.958. I have spoke with comp cams and their reply was the 921 would not work in the LS7. Too many shims would be needed to get the correct seat pressure. So why are so many venders using these springs in a LS7 which will not give the proper seat pressure for a stock motor more less one with a cam. Is there something I'm missing. I would like to find a dual spring that the manufacture recomends their spring for the LS7.

Thanks

dpracing

Do they offer they're beehive springs for the LS7?

You are talking to one of the people who broke 2 valve springs on 2 different motors.

Thanks............

J HEBERT

Give me a call dude, putting the beehives in my ETPs now....

extremecorvette

I used comp 918 springs on my LS7X heads

layjzay

Comp does not offer a spring for the LS7

layjzay

John who made them? I would sure find a dual spring to fit the EPT head. They may even take a larger diameter spring.

dpracing

Thanks. More research ahead.

Incon306

I lot of people are running the Patriot Gold and Extreme dual valve springs: https://www.patriot-performance.com/...ome.php?cat=51

IPS Motorsports

The 921's are floating around 6k from what I have seen. Check out the upgraded AFR springs!

extremecorvette

Most people have there springs set at 135lbs closed, 375lbs open, with a low rate around 350. At high RPMs if you don’t have enough spring pressure you will float the valve train. On my turbo car I will have pressure behind the valves on the intake side so I set my springs up 15 to 20 lbs higher. I went with 165lbs closed and 405lbs open. When installed and tested I get 163lbs closed, 406lbs open at my max cam lift of 0.622”. Springs are good for 0.750” lift. They also have a rate of 500. The higher rate of change on the springs equals faster the spring can move and keep from floating.

You need to find out what your install height is going to be with the parts your going to use, retainers, cups, and locators. Second find out what your max lift is going to be on your cam. Third always good to upgrade your lifters. I run Shafer’s they cost $540 for a set, Morels are great also they run $500.

I was told by Shafer son that the lifters I’m using can take 180-200lbs closed, 400-500lbs open with out any problems. He said he has seen a few guys with them run 180lbs closed and 450 open, rate 550 and they love them.

0MR Z

I have the upgraded AFR's in my car. I had originally ordered the comp 921 and after we checked EVERYTHING we came to the conclusion that they would not work properly. AFR makes a good spring. I do notice a few shops using the 921's and I wonder if they actually check this stuff before installing Even comp says no way to those springs for the LS7. Call em up and see for yourself. I sure would like to get the measurements LG and others use to know they are safe since thats what they install.

IPS Motorsports

I am guessing PAC is making these springs, just a hunch though.

Extrememcorvette,
I completely agree with what you have said, its hard for most to comprehend. It comes down to simplicity, people dont want to think about testing and shiming, and seat locaters ect, they want to order kits, which is why we have people trying the comp products, with out the proper knowledge.

layjzay

Does anyone know the factory seat pressure and open pressure? Will the increased pressue cause any other problems? Like increased seat wear or lifter failure.

Incon306

I believe the factory specs are 110 seat and 310 open.

ayousef

when I needed valvesprings, I gave Carlos a call, sent the payment, and while I was typing him a message asking if he sent them, the courier called me informing me they arrived.

You wont get better customer service.

I got everything needed to install them dual valve springs, and they are working FINE for about 7,000KMs already, nothing else needed. Drop him a line.

layjzay

what brand?

extremecorvette

I don’t know the factory seat and open pressure on the LS3 or LS7. I know the Comp 921 comp party # 26921 have Seat Load at 135lbs Open 400lbs Rate @ 408 that is with lift at 0.650” so open pressure at 0.600” lift is going to be less around 360-375lbs.

I used the Comp 919 spring. I found out what my install height was going to be with my locators, cups, and retainers I wanted to use. You can get retainers that are larger, will take 0.050” off the install height or locators that do the same. Comp took down the spring chart on the Comp 919. If I installed it at my install height I get Seat Load 165lbs Open Load 410lbs, Rate 550 I put my springs in at Install height of 1.205” and my max lift is 0.622”

http://www.compcams.com/technical/Ca...07/282-306.pdf


Comp has the springs down at Seat Load 194lbs Open Load 579lbs Rate 550 with 0.700”

Most of you are not going to put your own valve springs in. Any good installer can help you with this and if they can’t find someone else that can. I worked with Total Engine Air Flow to polish my heads and install the springs. They also test the Seat and Open pressure before sending the heads to you.

You need to make sure your lifters can take the pressure of the springs. Shafer and Morel can, stock lifters I don’t know. Comp R I was told would take it by Comp, GM racing lifters I don’t know. I always use a good lifter like Shafer’s or Morel, you pay more but good lifters and valve train get you all the power out of your motor, bad components cost you power. Shafer’s and Morels cost $500 for the total set.

Also make sure your push rods can take the pressure, most times you up grade to a harden push rod.

extremecorvette

Top valve springs Companys

PSI they make about all the Nascar springs the Best
K-Motion is Good
Comp is Good


There are very few companies that make there own springs in house. It’s always good to find out who does and what quality checks they do.

I know PSI load test every spring and match sets there springs with in 1-2 lbs of each spring. Expect to pay $350-700 for a set of springs from them.


I've used PSI, K-Motion, and Comp. 919 springs, coudn't find any springs that gave me the lbs I wanted for install and max lift open. PSI said they would make me springs for $1000 for the set. I paid $107 for my comp 919.

My new WarHawk 427 APS TT car is going to run Comp 919

layjzay

will a 919 fit without cutting head? 1.540 diameter

0Louis @ LG Motorsports

Yes, the 921 will bolt in, and it will control even the most radical lobe, as long as its shimmed with in .050 of coil bind.

The 921 coil binds at 1.040, where the PAC springs bind at 1.080.

The 921 isnt a drop in, and it needs shims, which we take care of on installs here.

Ask away, Ive been through a lot of this recently, and swapped springs back and fourth quite a bit.