Hydraulic roller lifters...not happy
 

Last weekend I had the opportunity to witness first hand what WILL result when running Competion Cams hydraulic roller lifters in a Gen 4 big block.

I am absolutlely floored over this design.It appears that the lifter bores on most big block Chevy`s are not exactly true, and if so,the tie bar rivet that joins the pair of lifters together eventually fails, the lifter spins and the roller flat spots and procedes to ruin the rest of the motor with all the shavings and loose parts involved when these things disintergrate.....this happened on Saturday. On Sunday, my buddy had the EXACT same problem happen to him. I had about 120 hrs, he had about 15 !!!

My block is junk, the axle for the roller went through a coolant passage, broke a piston and ruined one of the heads.

My question is this, is there a better alternative to the tie bar set up on a Gen 4 block? I really like the dog bone style retainer on the Gen 6. Is there a similar set up available for a Gen 4?

I`m leaning toward going back to a flat tappet hydraulic set up, they worked for years.

Looking forward to some experienced input.

Kurt.

Another reason, aside from the expense, why I stayed with flat tappet on my Mark 4's

I've never known why they build them that way I've never had any of their lifters last due to that sam problem the rollers are fine its just the welded rivet :confused: :confused: :confused:

Anybody make a good roller lifter for mark 4 blocks ? or are they not worth the bother & cost ?

The rollers are the way to go (boy thats hard to say )) but the isky lifters need to be used and I've had no problem with them
The factories have all switched to rollers due to how good they are ,you just have to be careful in the aftermarket and also know the hyd limitations

Roller Lifters
 

I used Isky (solid) rollers for several years on my 433" gen 4 with no problems. Big stick (RR-730B) and high RPM (8,000) - on street and at the track they were trouble free. Isky makes some of the best pieces available - i would take a look at their options.

my two cents

How does the Isky design differ from a Comp Cams roller lifter?

Could someone post a pic.

Bobby, It seems that the benefit of GREATLY increased longevity when running a flat tappet is far outweighed by any HP increase with the roller.

Thanks for the replies so quickly :cool:

Kurt

I hate to say this with the trouble we both have had with rollers but the when installed right and the right good parts used will out last and make more power than a flat tappet period ,,, I've had more trouble with flats but maybe its just me !!!! the factories sure love then and they've proven they can last

The iskies are alot heavier duty and designed with out the rivet
I'll post a photo later

I do like solid rollers 100 times better than HYD rollers and if you have a good profile you only have to adjust the valves every 90 hrs or lmore depending on the cam ,,I'll give you some good numbers if needed :D :D :D

I use the Isky pressure fed roller pin lifters. Red Zone.

Crower are good also.

Hey guy, I feel your pain! I elected to keep mylate model GM 502 blocks due to the factory lifter set-up. They simply do not break, no tappet haging out in the valley. GM has spent countless hours testing this combination and it has definately proven itself.
The downfall is you are limited to cubic inch. I presently have a 502 block, 30 over/4.25 stroke crank = 540 cubic inch.

Little Tommy

I`m sending the cams and lifters back to Comp today for inspection.They offered to replace cams and lifters for free or at a greatly reduced price after they inspect them.

Any recommendations on cam profiles? The motors are 454`s with blower pistons and 671`s with superchillers

Was running grind # 3376/3377 gross lift .613 intake and exhaust. Duration at .050 intake 240 exhaust 250 with 114 lobe separation

With this combo it would push my 1989 Top Gun to 5800-6000 spinning 25p Mirage Plus props.

At this point I am looking for a more reliable set up and I`m seriously thinking of going back to hyd flat tappet cams.

Thanks for the input guys!

Kurt.

Kurt don't do that ,,stay with the roller just install the right stuff
not that you did not try before .. but in a 741 crane and isky lifters and let me know what pressures the springs are on ,,I'll try and help its easy and done everyday don't throw in the towel

I agree with Bobby, you will only be going backwards. Listen to the master, he knows.

Wow what a shame
Biggus has one of the sweetest guns made
Since the block is junk why stick with the Gen 4?
These cam lifter discussions are good for me right now my motor guy was saying he liked Isky and this just suppoorts that

My sympathies

Klaw, thanks for the compliments!

I`m sticking with the Gen 4 because the stbd motor is fine and I have another block and heads ready to go. :D

What are your thoughts on running another Comp Cam (since I`ll be getting it for free) and using Isky or Crower lifters?

Biggus the 5800 to 6000 is bad for the hyd they blow up at that
really they weigh to much for the springs to control ,,the springs for you need to be heavy duty isky tool room springs and they and the isky lifters will last the comp cam is ok but put it in 4* advanced or even 5 and prop it at 5700 max 5600 is better ,trust me it will live and work

.
 

I was waiting to hear comment on anything above 5600 rpm
starting to break hyd. rollers down. :D :D

Would you recommend Solid rollers to him with his set-up
so he can still run the R's ?

Or is he better off staying with that?

By the way Bobby have you had a chance to get a picture
if ISKY's design yet on rollers?


Thanks for your continued help

Cougarman

heres the solid link for the high dollar killer ones , WE CAN GET A DEAL

isky

second

HOME PAGE FOR ISKY

Thanks for the links bobby. Isky is proud of them lifters huh? :D
I guess you get what you pay for !
Hang in there Biggus !!! Keep my next Cig runnin strong !!:D :D

yep birddog we can get them for less and the red ones are only for the toughest apps. 300. is about the price for solids that are killer

I had the same problems with solid roller lifters.. too many wheels stopped turning. I was using Isky lifters, but not the model you linked to Bobby.. very interesting.
My alternative was to go to a flat tappet .904 lifter from Schubeck. So far so good.. quick where is the wood.. Anyway about 60-70hrs so far and all is well.
I thought I would be in a pickle with the larger lifter bores if I want to throw my roller cam back it. but it seems I could go with the red zone and do well.. Hmmm back up plans always in place.

Good luck with your choice Biggus..

Oh yeah the place that bushed my block at .904 uses Jessel lifters with a tab on it.. and a slot in the bushing, but they do drag cars, so I didnt invest..

Dick

Hi Kurt:

Sorry to hear of your trouble. Lucky you had a Gen 4 in the pipeline...now our test with NEVRENUFF is going to be even more interesting.

Tom

I had these pics on the net already. Just remembered. Isky Red Zone. These are actually the solids that have the longer body for Dart blocks or Gen VI blocks

Part of one of my projects. How to find exact TDC and degree the cam.

Project Link *** CLICK HERE ***

http://www.havasubarney.com/iB_html/...6-oil_hole.jpg

http://www.havasubarney.com/iB_html/...essure_pin.jpg

Tomcat,

Yes, NEVRENUFF`s new motor should make a very interesting platform for your new Supercooler. I had really enjoyed working with you last winter and I`m looking forward to the next dyno session! :D

Kurt.

Biggus,

I am in the process of two 500 hp builds so as you know with twins the cost is double when you change on one you ussually change on two.
If you really feel that the comp cam is prone to failure why would you use them again. If they give you a free one put it in e-bay and gos with the isky and at the same time change the one on the starbord moyor as well because if it was the same build lot it will just fail also and it is much cheaper to do it now.

I find it interesting that there has been so many negatived about comp and no one has chimmed in that the have had similar problems with a isky

My hp500s are soon to be normakklty asperated 575 (dyno will tell)
we are using Isky.

Looks like me and Birdog will be bidding against one another if you ever seel the Gun.

Good luck,

Klaw

I HAVE HAD REPEATED PROBLEMS WITH LIFTER FAILURE IN GM BIG BLOCK APPLICATIONS. THE MOST RECENT FAILURE WAS A CAM FAILURE PRIOR TO LIFTER DESTRUCTION. THERE HAVE BEEN SEVERAL QUESTIONS RAISED AS TO VALVE GEOMETRY, END PLAY TOLLERANCES AT THE CAM BUTTON, BELT OR GEAR DRIVEN CAM, AS WELL AS LIFTER SIZE AND BORE. HAS ANYBODY LIVED THIS LEARNING CURVE AND SUCCESSFULLY SOLVED THE PROBLEM?
I HAVE GM TALL DECKS BORED TO 592 CUBIC INCHES. WE USE JESSEL ROCKER ASSEMBLIES. THE REED CAM IS CURRENTLY DRIVEN BY GEAR. THE VALVES HAVE A LIFT OF .709 INCHES. WE USE DART BIG CHIEF ALUMINUM HEADS AND THE MOTORS ARE LUBRICATED FROM A DRY SUMP APPLICATION. THE ROCKER ARM RATIO IS 1.7. WE INSTALLED OIL SHOWERS OVER THE VALVES AS WELL AS THE CAM. THE CURRENT SPRING PRESSURE IS 240 LBS. THE CAM BUTTON WAS PRESSED AGAINST THE GEAR CASE AND CAUSED WEAR ON THE CASE. WE RUN APPROXIMATELY 6200 RPM. WE ARE USING ISKY 372-96L0180 LIFTERS.

THE LAST FAILURE HAPPENED AFTER 8 HOURS OF USE THE LIFTERS TOOK LARGE SECTIONS OF THE CAM LOBES OFF. THE LIFTERS REMAINED WHAT SEEMS TO BE OK BUT THE CAM IS GONE.

that would be a tough one to help with the geomrty most likly did it as with jessels it has to be perfect or the springs seem light to keep the lifter on the cam at 6200 its most likly one of those but its a complucated system to do on here but great one for sure . its designed great ,you did use the good jessels I've not been able to make the sportsman jessels to live !!

C'MON Klaw !!!!! Don't do that to me !!!:D :D
did you get my E-mail?...Hope it was some help

I think everyone is focusing on the lifters and not the problem The problem is that the lifter bores in the block are not right. They can be bored out and bushed to realign them with the cam. The poor bore quality is not a problem until you start to increase spring tension and valve train geometry. This causes the lifter to push more against the sidesof the out of aligned bores and eventually leads to lifter/cam failure. Any lifter will fail depending on how bad the lifter bores are out of whack. 502's are notorious for this problem.(made in Mexico?)

In this case, the cam failed because the tie bar on the lifters let go at the rivet.

Do the lifter bores need to be bushed to get the lifters to last?

No,,, it could help ,,but most builders I know check this !!!!!

Everything you can do will help alittle

The quality control on these lifter bores is terrible. Some blocks are fine (just luck) and some are crap. If the allignment is off too much the lifters drag on the side of the bore and wear out. It can also cause the tie bar to break when the lifter gets too much friction on it. Stock motors are not as bad as worked motors. The increased valve spring pressure and higher lift cams put more sideways pressure on the lifters and makes the problem more critical. At a minimum, the alignment of the bores should be checked. Boring them out and bushing them insures they are correct. A good machine shop that has experience with this can do it relatively cheaply. ($400-450)

Jersey Tom has some very good points here. In the first link here Dave Reher expands on the severe tappet side loads generated by these blocks to the point of bellmouthing the bores themselves. The second is the link to the tappet bore sleeves.

http://www.rehermorrison.com/techTalk/28.htm

http://www.sdpc2000.com/cart.asp?act...=1625&pid=8374

http://www.cranecams.com/instruction...in/camfail.htm

hi,

hi, sorry for the mistake.i have been follwing this thread for a while and it is a problem of mine also. i contacted joe schubeck in Las Vegas and he has a new lifter ROLLER-X looks like the answer . i dont know if its on his web site yet. www.schubckracing.com

NEXT QUESTION. HOW DOES ONE VERIFY CORRECT GEOMETRY IN THE VALVE SYSTEM SPECIFICALLY LIFTER TO CAM ALIGNMENT? WE HAVE HAD INSTALLED LIFTER BORE SLEEVES AND STILL QUESTION GEOMETRY AND DON'T KNOW HOW TO MEASURE IT. IT LOOKS AS THOUGH THE LIFTER HAS CUT GROOVES AND EVENTUALLY CHUNKS OUT OF THE LOBES AFTER ONLY 8 HOURS OF RUNNING. THE FAILURES START FROM A GROOVE ON ONE SIDE OF THE LIFTER ROLLER AND TAKE OUT LARGE PIECES FARTHER UP THE LOBE. THIS SEEMS TO BE INCORRECT GEOMETRY BUT WE DON'T KNOW HOW TO INSPECT IT. THE BORE SLEEVES HANG BELOW THE LIFTER BORE IN THE BLOCK ON THE INTAKE VALVES APPROXIMATELY 1/8TH OF AN INCH. IS THIS RIGHT?? HOW DOES ONE MEASURE THE ANGLE OF THE LIFTER BORE WHEN DRILLING FOR THE SLEEVE?? OUR ENGINE BUILDER CLAIMS PARTS FAILURE AND SAYS USE ISKY CAMS THAT REED CAMS ARE SOFT. IS THERE AN OPINION ON REED VERSUS ISKY CAMS??

I use a jig I have for small and Big blocks to locate and correct lifter bores as do most of the other I know ,its very easy to check
with this .
I've never found a reed or Isky soft they both work very well I like the Isky better But they don't have many good book grinds anymore but do great custom and the ones in the book do run
Yes the mk6 does have tons of improvments in it but the mk4 is still very very much in demand .

The majority of component failures that occur, in situations other than max performance WOT conditions, are not due to a compromise in the integrity of the failed part. It usually occurs as a result of the part operating in conditions that are out of tolerance (spec) or incompatibility with related components. Under extreme conditions the importance of lifter bore axis indexing, correct spring rates, lubrication, and geometry become absolutely critical. It has always been my experience that if you examine the failed part as one component of the problem, rather than the problem, the solutions are a lot less expensive.
The cylinder case blueprints & dimensions for the Mark IV and Gen V big blocks are on pgs 110-113 of Chevrolet Power Factory Performance Guide which is available at most Chevy Dealers
This link shows one setup for the process
http://www.rottlermfg.com/catalogs/Rottler_F65.PDF