Valve Springs on stock heads?

[bison]

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.

Ive tested stock springs before and they were in the 60's at 1.75inch New ones might have been 82 on the seat. I agree with them that 80 would be all thats needed up to about 5000rpm. Problem is most guys are capable of going at least 100-200 more than that even with stock cams once they change turbos. A regular dose of leaded fuel will help those unhardened seats

 

[turbo nasty]

my guy

Should be my gut...LOL

FWIW When I removed my 98k stock springs and had my bud at the machine shop test them on the spring tester.

All but 2 were within spec but at the lower limit. Two being 3-4 lbs under the spec stated in the service manual

 

[TTipe]

Valve Springs

I think about 90psi on the seat works at about 5500-5700 rpm.Whats a Comp 979 pressure on the seat @ 1.75 ?? The 4.3l vortec engine valve spring is in that range.

 

[bison]

One problem that has not been mentioned here is that as you try to milk the stock longblock and run a lot of boost you increase the backpressure therefore you have extra pressure working against you as the valve is trying to close. This is why you really need a tall slick and keep the rpm down if trying to run 10's on a stock long block.

 

[pmparents]

Reggie West

Hey Reggie West, you say the LS1 beehive springs work well! What's your engine set up if u don't mind? Do you have the stock cam?

 

[charlief1]

Is there a beehive spring that's light enough to use with a stock cam? Aren't they more for the roller cams?

 

[Reggie West]

Hey Reggie West, you say the LS1 beehive springs work well! What's your engine set up if u don't mind? Do you have the stock cam?

We have been playing around with them on about 6 motors (maybe more) at this point. They are on stock iron heads, M&A heads, and TA's street and their strip heads.

You can use the stock beehive spring for any cam up to about .650 lift. Above that Comp has a different beehive spring for bigger cams than that.

This all started on a lark with someone a friend recommended to me. We decided to try it out and they work really well.

Advantages: 40 grams less weight on each valve. Seat pressure is (cant quite remember the number) about 120. We have not wiped out one cam lobe since using these springs. The motor revs up with no effort and you can hear the difference too. We had the first car on a roller dyno and you could hear it.

PM me if you want more info.

You do have to have a machinist do this. The valves have to be cut down in length and new keepers machined for them.

By the way these springs are on motors making stock hp levels up to 1000 hp. It works .

 

[dank GN]

I pulled my stock springs and tested them they were all in the 50 to 60 lbs range i replaced them with the comp 980 i could feel a slight performance gain on the top end.