I was reading through my "Chevy LS1/LS6 Performance" book and under the "Valvetrain" section, they author talks about rev kits for LS1s. They replace the factory lifter retainers with a guide bar and a set of coil springs that keep the lifter in contact with the cam lobe (what the valve spring WOULD do) but exert their pressure on the BODY of the lifter instead of the hydraulic plunger (thus preventing lifter collapse). With this extra pressure on the lifter, less pressure can be used on the valve springs. I have heard of these being used on other "old school" motors but never LS1s before.


Has anyone used one of these?

 

They mount on the factory lifters and help reduce valve float by taking the lifter weight off the valve springs.This means you can run lower pressure valve springs without worrying about float or lifters collapsing.Real good idea but sucks if you want to replace your Cam.Have to pull the Heads.

 

I really didn't see the "you have to pull the heads to swap cams" as a problem (I won't do it any other way.........don't like the risk). Any idea how much spring pressure could be droped off the valve spring? It seems to me that by moving some or the pressure off the valve springs, you will also make life easier for the valve, retainers, rockers, pushrods, etc.......

 

Agostino have this kit for LS1.I think is a good idea but i like to see the opinions on the people who use it!

 

Does anyone know how much a rev kit cost?

 

so when you swap cams you actually pull your heads , seems like a waste to me.

 

So if I understand this correctly, you have two sets of independent springs. One set pushes against the lifter and you still retain the valve spring. How can this be good? Seems like extra parts to break. Also, you have two springs now with (I assume) different spring rates? This doesn't sound good at all. Maybe somebody could further explain the theory behind it.
Chris

 

In addition to less likelyhood for lifter collapsing or bleeding I believe it is easier to design moderate stiffness springs to be reliable over extended periods of high rpm than very high rate springs.

 

It could be looked at as a waste, but I do not run the risk of having a lifter drop and thus get to pull the oil pan (which is MUCH more work than pulling heads). I have ARP studs so everything but the head gaskets are reusable. Just pop the heads off, swap my cam, and put it all back together.


1) Its often hard to get enough spring pressure at the valve only to work with high rpm/ramp rates without crushing the hydraulic plunger of the lifter. By moving some of this pressure down to the BODY (outside.....not plunger), you still keep the lifter in contact with cam lobe (which is what the high valve spring pressure would be doing) but the hydraulic workings of the lifter are not affected.

2) By having less spring pressure at the valve, there is less pressure (and thus stress) on the valve, valve seat, retainer, spring seat, rocker, rocker bolt, and pushrod. So parts last longer and perform better (less flex). This also means parts can be lighter weight and thus means higher rpm, even less spring pressure, and more life.

3) Really high pressure valve springs seem to brake more often than a lighter weight spring due to elasticity. Besides, people run two different spring rates all the time (its called DUAL VALVE SPRINGS) in order to prevent valve float (so they don't hit their float frequency at the same time). By having that spring on the lifter, the valve springs "basically" never "see" the lifter (its weight/mass) and as such they can do a better job against valve float.

 

I Dont Know Much About This Conversation But Couldenbt You Just Do Your Cam Before The Kit? Thus Solving The Cam Problem??

 

According to the e-mail I received from Wade at ARE they don't make the rev kit anymore. That was last year; I think that book is somewhat outdated for LS1 products. He felt it wasn't neccesary with the stiffer springs available on the market now, but contact ARE to make sure.

 

yeah....you would do the cam swap at the time you put the kit it (usually). What was mentioned was that if you wanted to change cams again (say you put a TR230/224 in and 6 months later said "I really want a G5X2"), you would have to remove the heads to pull the lifters otherwise they would fall when the cam was removed. I personally said that was not a problem (for me) because I would not want to risk the lifters falling even with the stock lifter guide.


so they are not made anymore .......if so, thats really too bad.....that was a really nice setup