The pinto motor he speaks of has larger and much heavier valves than a mod motor has.

 

If it's a static test, then I don't see how -- 15psi on the back of a 1.75" valve is only 36lbs. Weighing that against the other pressures on the top of the valve during the cycle, I can't see a significant problem.

From my experience with this style of head, if the valves float you'll limit the RPM of the motor -- the springs don't have the force to keep the lifters in check and the valves stick open.

Hopefully someone with more experience can shed some light.

 

We have been using a much higher spring pressure in a lot of our cylinder heads recentley and will continue to do so. Not only that we are going stiffer, alot stiffer and changing cam design. I really cant wait untill our newer style cylinder heads are tested and the gains are shown. You do not want to run a spring pressure that is really any lower than 95lbs in these trucks while running high boost. Its evident that in many High boost applications the valves will hang open and you will be hurting yourself for power. I have had alot of guys call me who just built their motor, added heads and cams, KB or MP and say they are low on power. Then I asked them all what their spring pressure is. All of them said at or about 75lbs which is way too low. I told them all I suggested to get a stiffer spring, I really hope some of them do and see the gains.

We have dyno tests and I know Charles from Magnum powers does too. I feel that it is a great Idea and Id challenge any one who claims this is not important to try it and see the gains. This really isnt too expensive to do when you consider that trucks that have this issue already have thousands of dollars dumped into them with engine and or blower upgrades.

JimIII

 

Hi Jim & Happy New Year

Motor arrived and looks ace.
Just one question - what springs are in mine?


Ricki - London UK

 

will these NEW springs be offered for sale seperately or only if you buy your packaged heads?

 

Since they are going to sell all of the parts seperately to install the GT block, I would suspect they will also sell the springs in a box also....or at least they would be crazy not too. There's going to be a lot of folks wanting those springs not just Lightning owners.
Dale

 

Dales right we would be crazy not too. However there are going to be springs to chose from so knowing what you need is important. It all has to do with the lift of your cams and how much boost you plan on running. Someone with a higher lift cam who has the same springs as someone with a lower lift cam wont see as much spring pressure. A truck that has a .580 lift cam compared to a truck with a .530" lift cam will see 95lbs of seat pressure, as opposed to 105 that the small lift cam would see. It is not just plug and play here, your combination matters!

Ricki,

Hey Happy New Years, hope you had a good one over there! You do have the stiffer springs in your engine!

JimIII

 

Thanks for that Jim

Check your in box for some photo's later

RFM

 

Interesting information.

Does anyone know the spring pressure of the Crower springs??? Their website says "high pressure" but doesn't say what they call high.

 

What if you took a BONE STOCK lightning and replaced the valve springs with a the appropriate stronger aftermarket ones.

Would you see an increase in power in the higher RPMs?

 

I'd sure think a "bone stock" lightning would'nt see any gain. But one with a 6lb pulley combo might be approaching the area where it would be questionable.

Rich

 

I don't think that anyone will be spending money to find that out. I couldn't afford to change the springs on a stock Lightning just to see what the gains are. Since they are the same springs as are in the N/A 5.4, I would think that 8 lbs of boost and an extra 100 hp would warrant a spring upgrade. I would assume that the power increase would be there; but, couldn't guess what it would be... Or if it would be a worthwhile undertaking. When I change mine, I'll be changing heads and cams, as well, to save on labor. No point in doing things twice if you can avoid it.