Koots

I'm not sure if it's ever been discussed, but I was wondering if there was any difference between the spring pressures between the two, both the checkball and plunger springs?

I can find a source for just the LS6 lifter springs, which I was planning on using for a budget lifter upgrade (if it even matters over a standard OEM LS-lifter), instead of buying LS7 lifters, but I might be barking up the wrong tree with all that extra work.

AUTOT3K

iTrader: (3)

are you talking about the whole lifter or just the spring inside them?
brian tooley had a really good write up on LS1tech about his experiments with different lifters but I cant seem to find the thread

Vortec350ss

iTrader: (20)

I'd like to see that write up

Koots

Me too!

I got this idea from a Cavalier forum, as they were trying to find a performance lifter option that would fit and using LT1/LT4 springs for the 2.2/2200 worked really well on cleaned stock lifters. Some of the newer 60* V6's were using the LS6 lifter springs, available from:

Lifter Springs - LS6

AUTOT3K

iTrader: (3)

so he's more so talking about his SLR lifters but still good info



"The lifter plunger height is the same as stock, and the plunger travel distance is about the same as stock. Which means in theory they can run the same preload as a stock lifter. However there are pro's and con's to running little preload or a lot of preload. Generally more preload will make less noise, however at high rpm's if the lifter may "pump up" due to valve loft, then it may not bleed down fast enough to seat the valves. At low engine speeds a stock lifter plunger can bleed down too fast and lose lift, which can also cause a tick.

Most guys are using .025"-.075" of preload on these lifters, and so far all have said the lifters eliminated the random tick they had with LS7 lifters. The plunger diameter in these lifters are a good bit larger than stock GM lifters, so I would imagine they gain hydraulic support from the increased plunger area which would also reduce bleed down rates.

In the spintron testing that I was involved in using stock lifters we saw .100"-.150" loss of lift from cycle to cycle at low rpm's, like idle speed. At low speeds the amount of time that the lifter is pushing against spring pressure is at it's greatest, and oil pressure is at it's least. This is what causes the lifters to bleed down.

At high RPM we saw upwards of .100" loft with the old Gold springs on a .600" lift cam. In theory if the lifter pumped up and then didn't bleed down fast enough it would hold the valve open and top end power would be lost.

You can see that having the valve train under control is as important as anything to do with the lifter. If you have too much lift, too much ramp speed, and too little spring pressure, the system will be out of control and damage will occur long term. It's interesting that in this scenario the spring could be at fault for not controlling the valve train, yet the lifter ultimately takes the beating and fails, then the lifter gets the blame. When lofting occurs not only does the lifter take a beating but the cam core does as well. So you have guys running crazy fast lobes like the LSK with springs like the old Gold springs and their cam core and lifters are failing. When the fault really rests on the cam design and spring pressure.

The next problem with lobes that are way too fast is, once you've increased the spring pressure enough to control them, you have too much open pressure to run with stock rockers and now the valve tips are taking a beating.

I've used LS7 lifters up to .670" lift and up to 7500 rpm, so to say a lifter has a RPM limit, really isn't correct. If the valve is light, and the cam ramp speed is low, then the valve train will stay stable. If the valve train stays stable then the lifter is able to do it's job without issues.

The SLR lifter body is made from a proprietary steel forging. The lifter starts as a solid slug and through multiple steps are formed/forged into what roughly looks like a lifter body.

How well these lifters hold up to aggressive lobe profiles is going to depend more on the pushrod stiffness/rocker mass moment/spring pressure/valve weight setup than anything to do with the lifter itself. If any lifter is lofted off the cam and then crashes back down, it's going to lead a short life."

Koots

Awesome information, I can at least get some professional perspective on this, other than skilled DIYers tinkering with things until they work or don't work.

Koots

I was looking more for information on the internal springs inside of the lifter, but all info is good info

Koots

From all the reading I've done, the LS7 internal checkball spring is stronger and is part of the reason for it's ability to handle higher RPM than the previous LS-lifters (from the reading I've done).

So for my LQ4, I'm just gonna buy a bunch of LS7 lifters and handpick the best. It seems to be the best bang for the buck option for me, as it will rarely see 5000+RPM and rarely has in it's time with me.