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Thread: new roller lifter design

  1. #11
    cjordan
    My comp lifter that failed only lasted 7hrs. The set before that had 42 hrs at change out. Can you feel any flat spots beginning to develop in the needle bearings as you roll the wheels?
    My cam was 280/288 @.050 with .750 lift. I toned down the new one a little, mainly by taking out lift.
    [ May 13, 2003, 10:28 AM: Message edited by: cjordan ]

  2. #12
    HammerDown
    Couple weeks ago "2 Guys Garage" had a Comp Cams tech on there show...even he said as good as they can be, there's just to many moving parts that can go wrong with Rollers...then he stated that Winston Cup cars use Flat lifters that are spining to almost 9000 rpm...guess the Winston Cup Cars don't want to chance a roller failure during a race...guess the few Ponys lost is worth it.

  3. #13
    DogHouse
    Haven't checked the others yet for signs of stress. Been too depressed so I just sit on the couch and drink beer. cry
    Just kidding, actually just been busy. I'll get back to the teardown here pretty soon.
    I thought NASCAR was limited by the rule book to solid lifters? Could be wrong there, I don't really follow it much. But, yeah, I agree, these things can be troublesome with big springs. I am going to investigate changing cam profiles and backing off spring pressure a little. I don't really spin the motor that high (6200ish) so I wouldn't think that I would need the monster springs. I'm sure Larry is going to give me an earful for running these big Dart springs that came with the heads.

  4. #14
    West Coast Dave
    Dog House, Your right. NASCAR Winston Cup rules state that only a flat tappet cam is allowed, no rollers. Other classes in the NASCAR world, ie: Southwest Series, Trucks, etc. allow rollers and everbody uses them. You can just have a much more aggresive lobe profile w/ a roller cam. To help keep the lifter on the lobe at high RPM and not have to rely only on the valve spring go w/ a rev kit. Pain to install but worth it at high RPM's.

  5. #15
    cookieman
    I am sd to see that someone else had the same problem that I had with my Isky solid roller lifters. I lost #8 Exhaust the same way,roller split in half. I did a little damage to the cam. I was told from Isky that loss of oil caused the roller to get hot , then when the oil would hit the roler it would burnish the metal off of the wheel. I had the cam refurbished and all the liftes refurbished. cost $300 If it happens again I will go with Lunati.

  6. #16
    blowngas
    cookieman:
    I am sd to see that someone else had the same problem that I had with my Isky solid roller lifters. I lost #8 Exhaust the same way,roller split in half. I did a little damage to the cam. I was told from Isky that loss of oil caused the roller to get hot , then when the oil would hit the roler it would burnish the metal off of the wheel. I had the cam refurbished and all the liftes refurbished. cost $300 If it happens again I will go with Lunati. Just curious---were you idiling the engine a lot or was it mostly under load the 7 hours it lasted? Roller cams won't handle idiling for long periods of time---Are you using isky springs that match the cam and lifters?---or at least equivilent ones?---I had a lunati lifter break the roller but suspect that the springs were not strong enough and the lifter started bouncing on the lobes and broke---but was turning it 8500---anyway---let us know what isky says--

  7. #17
    DogHouse
    Mine is a play motor so it saw plenty of idle time and only a total of a few minutes at WOT, roughly 6000-6200. Most of the time was just cruising between 2500-3500. Springs were the ones that came with the Dart heads, 270 lbs on the seat, 830 open. The cam is not extremely agressive so I would think that the springs were more than sufficient. I actually wonder if they're too much for my use. These Isky lifters have the pressure fed oiling to the roller so they were supposed to be ok for idle. Maybe not!

  8. #18
    Infomaniac
    I would not have ran that much spring pressure.
    Hard on parts and a big waste of HP.
    It is a strange situation. Too little spring pressure is worse.
    Those lifters are the best for extended idling. I put them in the quad rotor engine dynoed yesterday. 150 # on the seat.
    I run the Crower version in the Cougar. 250 # on the seat. The cam only requires 180# but I spin it close to 8k.
    [ May 17, 2003, 11:24 AM: Message edited by: Infomaniac ]

  9. #19
    HBjet
    So what did the Quad Rotor dyno at?
    HBjet

  10. #20
    Infomaniac
    We had difficulties. Could only get 7 lbs of boost.
    It made 970 @ 6300 7lbs on 93 octane unleaded.
    Dustin Whipple and Bobby Daniels are helping troubleshoot it.
    Still trying to refine this video. Someone give it a try and see if it runs. Not your average dyno run. Plenty of steam and water.
    Dyno Pull
    [ May 17, 2003, 09:57 PM: Message edited by: Infomaniac ]

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