Ok, I am pondering the use of a hydra rev kit and comp R lifters with my turbo setup. Normally, it wouldn't even be a question.. as I feel the above is great for a hyd setup, but since I am only reving to 6600 or so, and I am trying to scrape together enough cash to get this thing finished up.. so I am thinkign about selling my Rs/rev kit.

the cam is a 217/213 with .550/.530.. short duration, high lift.

I am worried about keeping the exhaust lifter on the lobe with short duration high lift.. the grinder says that with 125 on the seat, I don't need a rev kit....

any thoughts? I want it done right.. but i really could use the extra few hundred

 

Local buddy/board member just had a nice Comp R lifter explode on him in his 383 car. He isn't happy considering the car was fine for maybe 2000 miles. He's now going solid roller and much bigger.

Personally i'd do a rev kit on any engine. It's kind of like cheap insurance and it lets the valvesprings do their job without any excess stress on them from the lifter's mass.

What kind of preassure will your intake valves be holding back? 20-30 PSI? hehe

 

Having a solid lifter go bad on me a while back id say go with the rev kit..Im sure you know it wont add any power like the mags claim..Well maybe if you choose the wrong valve springs and have valve float way too soon..Just for the fact that the lifter will stay in the block is enough reason..I'll take a sputter at 6600 over a loss of oil pressure any day..

I dont really understand why you would think that the rev kit will help the springs out in an accountable way..Valve bounch will happen anyways since the rev kit cant control the valve in any way shape or form from its location and design..Maybe im missing something here..To me it seems that one would have to pay extreme close selection to spring selection in that case..RPMs, spring installed height pressure and cam lobe profile would be more in par with valve control/bounce to me..Possible the springs if they were changeable with different spring rates would matter but i cant seem to figure out how this would be tested in a running engine and proven for that matter..From what i know the base circle load is 30-50lbs and varys due to lobe lift..You wouldnt want to run a softer spring because that would seem to promote valve bounch and with a forced induction setup could in extreme cases have severe problems closing teh valve at the proper time and rate...If im wrong then im wrong but from ive gathered from many a seminar as well as studing the purpose of rev kits the only real purpose is to keep the lifters in place..Thats with teh proper valve springs mind you since it could be far better claims on a hydro setup but if your hydo cam runs that far into rpm and needs more control you should be running a solid lifter cam at this point..

 

I've used rev kits/r-lifters in the past when using larger hydraulic rollers.

On my current setup, I decided not to because of the small cam.

It's a Cam Motion 214/222 .544 lift. I'm using stock lifters and no rev kit, comp springs with 135 on the seat, and titanium retainers.

It made peak power at 6,100, but I pulled it to 6,600 on the dyno and it only lost 25hp up to that point (no valve float).

So, IMO, I think you would be just fine with stock lifters and no rev kit.

 

you are right, it won't help with valve bounce.. but it will help to control float. the lifter, althought it doesn't move as much/fast as the valve it is the heaviest part of the valvetrain.

 

Cool for a minute there i though i was lost...

 

Jordan: my intake lobe is 214 with .530" and it's not a problem with stock GM lifters. However, my rev limiter is set at 6,200 and I shift at 6,000rpm.

Rich Krause

 

You've got ther right idea, the hydra-rev kit is only helping to keep the lifter on the cam lobe. A oem lifter is heavy at 122 grams.
I'm changing lifters in my car tomorrow and I plan on putting the rev-kit spring on a pressure tester. I'm thinking about thirty pounds closed, so that's like 48 lbs of valve seat pressure (1.6 rocker) I think? or am I hitting the pipe to much?

 

fyi, the rev kit has no effect on seat pressure at the valve.

 

You're a roadracer.. I wouldn't hesitate to throw one in with all that banging up and down through the box going on. If you didn't have it though.. hell I wouldn't worry either way.

 

Jordon,

If you do decide to dump the Comp R's.....I have an immediate buyer. My buddy is in the middle of rebuild, and is dire need.

Send me an e-mail if you wish....