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Re: Rocker Arm Failure: Was I asking to much?
[Re: qwkmopardan]
#1946112
11/06/15 03:28 AM
11/06/15 03:28 AM
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Joined: Jan 2003
Posts: 1,292
Tucson AZ,
MadMopars
OP
pro stock
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OP
pro stock
Joined: Jan 2003
Posts: 1,292
Tucson AZ,
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What brand rocker and how much spring pressure? Rockers are C.A.T. Spring pressures were 135# @ 1.990 and 400# @ 1.450 last time I checked. FWIW, springs are ISKY 9005's.
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946150
11/06/15 08:55 AM
11/06/15 08:55 AM
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Joined: Jun 2010
Posts: 1,144
wellington ohio
68-scatpack-rt
In thin ice
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In thin ice
Joined: Jun 2010
Posts: 1,144
wellington ohio
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Hecho in china.
No need for (and not a good idea anyhow) for roller bearing rocker arms on a street driven car.
That said, was the carnage isolated to those two arms or do they all look like that?
If it's all of them, I'd look elsewhere for the cause as the arms were, most likely, a secondary failure.
Last edited by 68-scatpack-rt; 11/06/15 08:59 AM.
unions....the folks who brought you the weekend!
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946205
11/06/15 12:12 PM
11/06/15 12:12 PM
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Joined: Oct 2012
Posts: 235
Gilbert AZ
tsanchez
enthusiast
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enthusiast
Joined: Oct 2012
Posts: 235
Gilbert AZ
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I assume the cam lift is mid .500s then, should have been no issue but either the rockers were not up to the task or there was unhappyness in the valvetrain.What do the others look like, seems that the alum was soft.
I run special harland sharp shafts on my car with .794 .747 lift mech roller with 260 seat 700 open springs. This year was the 2nd drag week on them with no issue. 1st year I was running st harland sharp rockers and they broke at the pushrod side, sent them back and had the geometry changed.
On a side note, my cam lashes at .028, for drag week I set it at .015 so there is less hammering.
Last edited by tsanchez; 11/06/15 12:14 PM.
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946245
11/06/15 12:55 PM
11/06/15 12:55 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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you guys can not compare CAT to Harlands.
Gen 3 power 6.22@110, 9.85@135
Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Rocker Arm Failure: Was I asking to much?
[Re: sixpackgut]
#1946253
11/06/15 01:04 PM
11/06/15 01:04 PM
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Joined: Jan 2003
Posts: 1,237
North Central, Indiana
Roughbird72
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,237
North Central, Indiana
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you guys can not compare CAT to Harlands.
There's an understatement! lol
Last edited by bubby440; 11/06/15 01:05 PM.
72 Plymouth Roadrunner 11.08@123.25
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946263
11/06/15 01:15 PM
11/06/15 01:15 PM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,012
U.S.S.A.
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Boy did you get lucky , I hope the broken one didn't cause the valve keepers to pop off and drop the valve ?
It appears that the rockers are clearancing themselves on the retainers by the looks of the one that didn't break ?
Do yourself a favor and pitch those ALL in the scrap pile, the valve train is not a place to skimp with cheap chinese GARBAGE.
running up my post count some more .
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Re: Rocker Arm Failure: Was I asking to much?
[Re: JohnRR]
#1946321
11/06/15 03:08 PM
11/06/15 03:08 PM
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Joined: Jan 2003
Posts: 1,292
Tucson AZ,
MadMopars
OP
pro stock
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OP
pro stock
Joined: Jan 2003
Posts: 1,292
Tucson AZ,
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Boy did you get lucky , I hope the broken one didn't cause the valve keepers to pop off and drop the valve ?
It appears that the rockers are clearancing themselves on the retainers by the looks of the one that didn't break ?
Do yourself a favor and pitch those ALL in the scrap pile, the valve train is not a place to skimp with cheap chinese GARBAGE. These are the only two that came apart. There are several others though that the roller shafts have come loose on. I assume the shafts getting beaten out is the early stages of the failure shown above. There is no interference between the rocker arm and retainers. The witness marks above are from the rollers coming out, thus utilizing the rocker body as the contact point. I was very lucky it didn't drop the valve. I attribute that to a higher power, it really should have dropped both valves. I am guessing at this point that the failure was partly due to the high lash at moderate RPM for long duration mixed with poor quality rockers. As I continue dissecting things I'll know better though. At this point, I am curious to know what rocker arms are suitable for use in the conditions I mentioned earlier. Will I find a rocker suitable for that application or should I really be looking at a G.V. overdrive or alternative way to reduce engine RPM at cruising speed? Even the valve stems look a little rough. Is 3000 RPM for long duration just asking to much? Perhaps with the lash requirements it was?
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946329
11/06/15 03:28 PM
11/06/15 03:28 PM
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Joined: Jul 2004
Posts: 19,317
State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,317
State of confusion
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What brand rocker and how much spring pressure? Rockers are C.A.T. Spring pressures were 135# @ 1.990 and 400# @ 1.450 last time I checked. FWIW, springs are ISKY 9005's. Crane golds should fit that deal and did for me no problem.......
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946354
11/06/15 03:59 PM
11/06/15 03:59 PM
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Boy did you get lucky , I hope the broken one didn't cause the valve keepers to pop off and drop the valve ?
It appears that the rockers are clearancing themselves on the retainers by the looks of the one that didn't break ?
Do yourself a favor and pitch those ALL in the scrap pile, the valve train is not a place to skimp with cheap chinese GARBAGE. These are the only two that came apart. There are several others though that the roller shafts have come loose on. I assume the shafts getting beaten out is the early stages of the failure shown above. There is no interference between the rocker arm and retainers. The witness marks above are from the rollers coming out, thus utilizing the rocker body as the contact point. I was very lucky it didn't drop the valve. I attribute that to a higher power, it really should have dropped both valves. I am guessing at this point that the failure was partly due to the high lash at moderate RPM for long duration mixed with poor quality rockers. As I continue dissecting things I'll know better though. At this point, I am curious to know what rocker arms are suitable for use in the conditions I mentioned earlier. Will I find a rocker suitable for that application or should I really be looking at a G.V. overdrive or alternative way to reduce engine RPM at cruising speed? Even the valve stems look a little rough. Is 3000 RPM for long duration just asking to much? Perhaps with the lash requirements it was? Yea the rockers are cheap, but I think your lash or pre load was not right. IMO that's what tore up those rockers. I could be wrong but I doubt that 3000 rpms like on the highway would hurt those rockers. I think your spring pressure is low and any rocker can handle that. I have run the crane gold rocker too on the street on both a big block and a SB since 1985, all my rockers are original. You don't need needle bearings on the shafts, that makes no sense to me.
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Re: Rocker Arm Failure: Was I asking to much?
[Re: Twostick]
#1946375
11/06/15 04:29 PM
11/06/15 04:29 PM
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Joined: Jan 2003
Posts: 1,292
Tucson AZ,
MadMopars
OP
pro stock
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OP
pro stock
Joined: Jan 2003
Posts: 1,292
Tucson AZ,
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What are your cam specs? Maybe not enough spring pressure? Spring surge/harmonics can tear up stuff sometimes as bad as too much pressure especially with some of these aggressive lobe profiles.
Kevin Cam is the Mopar 296/557 Purple Shaft. Spring pressure is slightly high for the application. Valve train geometry was spot on but coil bind was not ideal. At full lift there was still miles of clearance before coil bind. I would say about half of the valves appear to have rotated which I had not seen in the past. I had run 1.5 C.A.T. rockers previously with no issues other than replacing the junk roller bearings years back. I installed these 1.6 C.A.T's just before Drag Weekend though. They were still new in the box prior to this trip. Lash was confirmed several times prior to closing up the motor. The adjusters are still tight and at first glance I see no bent push rods.
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Re: Rocker Arm Failure: Was I asking to much?
[Re: MadMopars]
#1946432
11/06/15 05:30 PM
11/06/15 05:30 PM
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Joined: Mar 2008
Posts: 860
lancaster,california
johnnycuda
super stock
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super stock
Joined: Mar 2008
Posts: 860
lancaster,california
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Hey Trent, I just installed a set of Comp Cams Ultra Pro Magnums,#1621-16, they're a moly steel, were quieter going down the road than my aluminum set, my spring pressure around 220 on the seat and 430 open if I remeember right, .600 lift solid roller, no problems with them on Drag Weekend or mdriving around here before hand.
1970 'Cuda,Lime Light,499 Indy S/R's 10.70's @125,street driven ALOT!
1966 Barracuda 360,now a 5spd,Hemi Orange,Hot Rod Air,
New daily driver-2003 Ram 2500 Cummins 5.9
'69 Valiant 2-dr, sleeper!
New project---1938 Dodge truck, plan is a 360 with a A500, AC, Calvert rear susp., rack and pinion front with coils.
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