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| 12 degree lifter life... | Login/Join |
DRR Pro |
Had this conversation with a friend of mine who bought a 598 12 degree motor, Hes had plenty of Valve train issues.. How many passes normal on lifters? "Just Shut Up and Race" Brian Martin Martin Racing 5.50 126 | ||
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| DRR Pro |
BAM...in my 9 degree with at least 400 plus with no issues at all.. | |||
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DRR Trophy |
There is no quick answer to how long the lifter would last without knowing how well the valve train is built and put together. Plus, with the spread port stuff having offset lifters and such, that can always cause the risk of failure to go up. I have about 150 runs on a set of Crower .842's HIPPO needle bearing lifters, cam has smaller lobes .475/.457 but still has 881/825 lift with PAC 1248's in my 14 degree motor. I check lash as much as I can and also plan on swapping them out for rebuilt ones this winter. Now, if you had bushed .904's on a 55mm cam core cam and the lobes weren't super aggressive, I wouldn't worry about going 250-300. The fact that Whomp got 400 sounds like he's got a very good setup and is meticulous with maintenance (correct me if I am wrong). LOL Nick Craig 1971 Camaro Split Bumper 376ci LS3 | |||
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DRR S/Pro |
My blown 12° @ 8400 with .937 Isky bushed lifters never had an issue that was the lifters fault in over 200 passes. 272" Spitzer 540 Chevy The Blower Shop XR1 FTI XPM Series Converter FTI Level 6 Powerglide 3.69@199 .916 60' 2017 Bradenton Heads Up Madness Open Outlaw Champ 2018 PDRA T/D #5 2019 PDRA T/D #2 2020 Retired From T/D Competition.... 2020 Bradenton NMCA Hemi Shootout Winner 2021 getting back into bracket racing with a Gen3 Hemi powered 87 Cutlass. | |||
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| DRR Trophy |
NC3x58 described it well. We run .937 needle Bearing Jesel's on our 615 11* and have not had a valve train issue. But we only put 100-150 runs on them before they're rebuilt. Does your buddy do a burnout on the chip? From what I've seen and been told by our engine builder, that's the biggest cause of valve train issues on big spread port stuff. A guy I know had a brand new 14* 632 built this year and he's had valve train issues three times and he beats it hard on the chip. Could be coincidence but I've certainly noticed a pattern. | |||
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| DRR S/Pro |
Valid point. https://rehermorrison.com/tech...abusing-your-engine/ Illegitimi non carborundum | |||
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| DRR Pro |
He sold the motor a year ago. Talked to him yesterday and he just had bad things to say about 12 degree stuff. I said man to many run that stuff for it to be that bad.. I dunno i was just wondering for myself really "Just Shut Up and Race" Brian Martin Martin Racing 5.50 126 | |||
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| DRR Pro |
but yea was in a digger with burnout limit. No idea what he set it at "Just Shut Up and Race" Brian Martin Martin Racing 5.50 126 | |||
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DRR Sportsman |
Valvetrain life has EVERYTHING to with proper lobe shape and spring pressure. It is critically important to have a stiff enough pushrod to properly transfer the energy without flexing. I have personally gone over 500 runs with .904 bushed lifters and a very large lobe. With 1.85 rocker arms, valve lift was close to .985 lift. At one point, the electric shifter failed to operate because of a broken internal wire at solenoid and the engine went as high as 10500 rpm. At tear down the valve springs were still usable and only down 30 psi on the seats. Often times a milder cam can rpm higher because the valve train is smoother. It is not a 12 deg problem, although I do recommend steel rocker arms whenever you have offset rockers. My 12 deg heads, use steel offset rockers and aluminum non-offset rockers. | |||
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| DRR S/Pro |
My jesel keyed .937's have been in service since 2007. Have no idea how many runs that is, but way north of 2,000. 12 degree, 9000 rpm .991 60' 4.36 @ 159 so far..... 6.86 @ 198 trying for more...... 533" single carb 235" Harrison 4-link | |||
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| DRR S/Pro |
Describe the valve train issues! You should not have any issues with that setup when properly assembled with the right parts! I ran those heads with Isky Red Zone bushed .842" lifters for 3 years with no issues, well over 400 runs and they are still good to go. The springs had 335 lbs on the seat and 1000 open. Those heads do not need offset lifters. I also know a others with these same heads that run more aggressive cam/spring combo's, again not one issue! Find the real problem and fix it. | |||
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| DRR S/Pro |
Why did you go AL on the ex rockers? If you break one of those it's likely to end badly, break an intake and its not big deal other than a lost round! | |||
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| DRR Pro |
Motor is sold. It did have offset lifters. Just had a conversation with him and he just bashed 12 degree stuff. I just wanted to know more info about it. He had a lifter failure after he purchased the motor and he broke a rocker arm and bend a push rod.. That's all i know really. "Just Shut Up and Race" Brian Martin Martin Racing 5.50 126 | |||
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| DRR Top Comp |
When you brake an exhaust rocker , you break an intake lifter same hole and bend the pushrod. Fairly common. I finally got steel rockers on this 1" cam 400 plus on the seat 1400 plus open. I was sweating it for a bit there nice build, the customer wouldn't budge off the aluminum rockers. No worries now.  This message has been edited. Last edited by: Mike Rietow, | |||
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DRR Trophy |
Two 12 degree motors with .904 Isky Red Zones. One has an aggressive NA cam, one has a nitrous cam. No issues at all, but did rebuild the NA motors lifters after 350 runs. | |||
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