michael101

iTrader: (21)

It looks like more than a few people are running into issues involving the Comp 'R' lifters. I've been doing a lot of reading and find mention of that in various threads. I thought it would be good to have one thread for everyone with an issue to jump on, maybe pool our thoughts and come up with some answers.

My combo includes Crane dual springs, Comp Pro-Mags, Comp 'R' lifters, and the FM11.

My problem surfaced after the install of the FM11 and Pro-Mags. The lifters were in the car before and seemed to be doing fine. The former cam was a custom design.

What I am experiencing is either valve float or lifter bleed-off (I think), occurs around 5500rpm. The engine kinda goes flat, struggles to get through this range. Does fine up to that point.

I have done a few ATAP runs and see no problems with the programming, no fuel issues, no knock retard, etc.

I have tried messing with the pre-load, everywhere from 0 to ~25thou. and do not see a difference. I have also check for clearance between the rocker and the springs.

Country Boy

iTrader: (24)

Lifters "usually" dont cause valve float. Its the springs that cant keep up. Ive spun my Rs up to 7100 a couple times. The only problem people seem to have is noone wants to buy adjustable rockers or shim the rockers to get the preload right.

BLUEBALLS ZZ

iTrader: (2)

i have dual comp springs and the comp r with a 236 242 600 plus lift. i am very happy with them at this point. don't have any dyno's on it till the 17th when i get it dynoed tuned. but she pulls hard all the way up "sotp"

Steve Burger

iTrader: (33)

I have comp R lifters with a 231/237 +2 .59x lift cam AS S2 5.3 heads and 977 springs. Initial dyno showed the HP curve falling off at 6300 RPM. I made good HP but the graph looked bad. I added HS rockers and shimmed the lifters to ~ 1/8 turn past zero lash. I redynoed yesterday and the HP curve between 6300 and 6750 is flat. We ended the test at 6750. Just goes to prove that the CompR lifters work when set up correctly.

Crowley

So the setup from Absolute was not correct and you had to correct this? I have that same setup comeing and I want to make sure I get it set up correctly.

thanks,
Crowley

Steve Burger

iTrader: (33)

I had Speed Inc do the install.They forgot to check preload. Absolute sent the right stuff. I have 7.35 Push Rods. There is no way around adjusting the Comp R lifters. .030 shims would equate to 7.32 PR length. These are not off the shelf items.

This is just part of setting up these lifters.

Pro Stock John

iTrader: (34)

First off, let's just debunk a few myths here.

Comp R lifters and Y/T rockers are just mechanical parts. R lifters are not amazing things, they are just very good lifters. Ditto on the Y/T's.. good rockers at a good price.

The culprit for most combos are the valvesprings. Want a good read? Look for David Vizard's article in MM&FF that shows him testing 918's vs another set of springs. You can only expect so much from a valvesprings.

You need to research what springs work best for your application.

I am running longer valves so I could get the installed heighth we desired with my Crane springs. I pull the motor to 6900 right now, but next time we'll pull it to 7300.

You might shoot for 130 on the seat, and be getting less than that. Usually they are 10 less than what you are shooting for. I'll try to start a good spring thread after I make a few phone calls to get some good data to use.

Steve Burger

iTrader: (33)

I agree with John. The R lifters are good. The HS rockers are good. The Absolute package I got is great.

But.......

To make all of these parts a great performer required the right setup. Yeah it was a pain to shim lifters but it's done now and all is good with the world again. Would I do it over? Yes. Would I get adjustable rockers? Yes if there was such a thing that did not cost more than the national debt.

At the end of the day I have a strong running car with one component being Comp R lifters. They do not make or break the package. They compliment the selection of parts.

crainholio

iTrader: (2)

I'll keep an eye out for the spring thread, got good spring dyno data both at 1.800" installed height and +0.563" lift on my new Crane duals before I installed them.

As for the Comp-Rs, I had one fail on my L98 engine last season...found the steel plunger retainer/preloader in two pieces stuck to my oil pan magnet after a day on the Pocono North road course.

Comp was very cool, sent me a whole new set after I returned mine, but next time around I'll just go solid roller. It's really not that much more trouble than properly setting up Comp-R lifters, and you can kiss your valve float and lifter pump-up problems goodbye.

John B

iTrader: (10)

Ditto with PSJ on this one. I hate to say it but too many people just aren't experienced enough at setting the entire combo up properly. I have custom valve springs which basically match the spec's of the Comp 977's(actually slightly exceeds them), the Comp R lifter with 7.350" PR's and use the too often bad mouthed Yella Terra's. I verified that everything is set-up per spec and the set-up works flawlessly, in my case with no shims under the rockers. I only have about 400 miles on my new LS6 motor and have had it up to 6500 RPM in 4th ger on several occassions breaking the motor in and I am proud to report zero issues with either valvetrain noise, valve float or anything else.

Clearly everyone that is having problems or issues with either these lifters or the YT's are not following the recommendations for springs, lifters and lash. You can't just pick and chose which components you are going to use and match. It's just that simple!

Unaffliated Racing

iTrader: (15)

John, please give me a call if I may be of help..better yet call me anyway..I need to holla at ya.

Crowley

Since I don't know anything about valvetrain .. I don't doubt the Absolute package is a great package ... I now have to put trust in a shop to set everything up correctly though (since I have the 977 springs and CompRs) ...

I am definately thinking about selling my whole setup now since I really don't have the $$ to keep taking the heads off for adjustments ....

Crowley

Steve Burger

iTrader: (33)

I never took the heads off once they were on. I did take the valve covers off and shim the rockers. There is a big deal here over very little. The Absolute package wil work VERY well. Set it up right and never touch it again if that is what you want. just work with a shop that knows how to set preload. I never set preload on an LS1. I did not take long to figure out and do once I got the valve covers off.

Country Boy

iTrader: (24)

Heres a new thought. Ive done some reading on the Rev kits..... Did anyone ever think that with the VERY aggressive cams and lobes we have and the high lift cams that the lifter may be losing contact with the cam as it runs up the ramps, making it seem like valve float? I noticed the way the rev kits are made that theres springs that sit on the lifter body that keep the lifter planted. You can only do so much with the valvespring before it affects the way the lifter works. Ive also read that with the hydrolic roller lifters this becomes a problem ~6800 RPMs. Just about all the "valve float" issues seem to be with the big cams in the high RPMs?

Any thoughts?

michael101

iTrader: (21)

I have a thought

Thank you for finally thinking 'outside the box'. This is the jest of the question that I've been trying to put forward. About the only responses that I've seen center around 'mine works, so should yours'.

With all the possible variables involved in a valve train set up, it isn't very likely that we as a group know all of the answers. And it is possible that some of us might be experiencing a valve train problem caused by the combination of the newer aggresive cam lobes along with the 'standard' valve spring/lifter combinations.

Again.....thank you Country Boy for being open minded

SStroked 410

Got a question

Whats would be a good valvetrain combo? I was thinking HS rockers and comp R's but might need adjustible rockers?
I will have comp 921 springs, ferera 2.08 1.60 valves, big cam see sig, reving the car to 6,500-6,800rpms

TIA