While i was on their site looking heads it will take me forever to afford i noticed the hydra rev kit. im not quite sure i understood how it works. How much do these sell for? would it be worth it? the cam im putting in will redline about 6700-6800. would i benifit from one of these? the results on the site look very damn impressive! let me know you alls expert opinions!

 

As I understand it, the spring-pressure of the rev-kit pushes down on the lifter body, thus allowing the lifter to remain in contact with the camshaft at higher RPM's.

Also means that the valves will close faster, as they are not trying to push the mass of the pushrod/rocker/valve back on closing. Means you can get the benefit of a higher-revving cam without the power-robbing effect of higher spring pressures to keep the valvetrain where it's supposed to be in the upper RPM range.

I've heard it argued both ways, they can be good or bad. My machinist doesn't use them. He believes in the K.I.S.S. principle (Keep It Simple, Stupid) and the more "stuff" you have moving around in there, the more chances something can go wrong.

 

I figure if youre running it over 6500 alot, then its ok to use the Rev kit.

Thats just my opinion though.

 

I read the same thing on the AFR website and bought one to go with my new LPE 219 cam and LPE massaged D113 Heads and new valve springs. Then I tried to install it in the engine sitting on an engine stand. First I tried putting the spings from the rev kit in and bolting the head on the block. I could not compress the head down far enough to get any bolt started. Then I bolted the head on alone and tried to insert the spring and the alum bar under the head. Again I couldn't do it. I have since bought the small engine spring compressor from AFR to collapse the springs one at a time to get them under the heads. That seems to work perfectly. Another tool added to collection. Thanks for motivating me to get this part of the job done. The engine sits in the cold garage awaiting warmer weather
...Brrrrr..snowing again in DC..

 

What do they cost?

 

someone told me about 175. not sure though. if thats hte case sounds like a deal

 

This another one of those things where the jury's still out for a street engine.

Back to back dyno tests printed in one of the mags showed a loss in power using the rev kit. Also, I believe they will only fit certain make lifters too.

However, rev kits are pretty common stuff on all out racing engines. About half the BB engines I built had them and half didn't.

Now, on the other side of the coin, ISKY swears by them. Their tests show that they prolong lifter life.

If you think about it, when running a mechanical cam, there's always a lash setting which can be as tight as .010 or as wide as .030 maybe more.

ISKY told me that because of the lash, the lifter gets pounded onto and off of the cam's ramps. This flattens the bearings in the lifters' roller wheels and, in time, causes the roller end of the lifter to fail. So, without a kit, lifters don't last nearly as long and should be considered an expendable item, like oil. Run 'em for a while then trash 'em.

If the roller end fails at speed, you can imagine the damage the bearing material will cause flying around inside the engine.

Hydraulic rollers don't have the same pounding problem that mechanicals do and the kit did allow higher rpms on the dyno runs. It's a way of increasing spring pressure without over-whelming the roller lifters' max pressure handling capability.

When you go over 350# of open pressure with hydraulic lifters you've just entered the twilight zone. I believe TPIS says 325 is max to use (I'd have to check their booklet to be sure on that one).

IKSY's explanation makes sense to me.

Jake

 

hmmm i may end up getting one