Rocker failure
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Rocker failure

  1. #1
    Senior Member kidd bill's Avatar
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    Default Rocker failure

    Less that 15 hours on this rocker, exaust side. Its a Comp Cam. Solid roller with 800 lift, dont have the spring pressures handy but its alot, turning 6300. Checked and there is no bind or anything else out of the ordinary. Luckily it broke just off idle and the pushrod actually stayed in place. It was still opening and closing the valve, just a bit of slop lol. I found the lash cap in the head and nothing else seems beat up. Just curious if this is the limit of a stud mount rocker or am I missing something. And I know everyone will tell me shaft mount is the only way to go and thats what will be going back on it but just wanna make sure I dont have other problems.
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    Boat Nut sleekcrafter's Avatar
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    Unless you guide clearance is too tight, on the exhaust. Looks like you got lucky!
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    Senior Member kidd bill's Avatar
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    Guide clearance should still be good, I still need to check to see if the valve got hurt but the tip doesnt show anything and the rocker was still riding on it.... just a bit further forward lol. I am fairly lucky when it happened, I was just getting out of the no wake zone and just started to give it some throttle to get on plane when all sorts of funny noises happened, glad it didnt happen further out cause it was pretty rough and busy.

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  6. #4
    gn7
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    You have to love the aluminum rocker business. So many variations, many from the same manufacture( which is very seldom the name on the rocker). Who knows who made this rockers. I have an idea, but its NOT the most common Comp rocker I have seen.

    At first glance you might think this is the same rocker. But its not. Compare the side of the rocker around the trunnion bearing.


    Now check the sides of this bargin basement el cheapo POS that even Comp doesn't recommend for roller cams. But you notice it doesn't have a kick tail over the push rod. Also notice how the nose axle extends out past the side of the body. Not exactly the same rocker. But is it the same material? This particular Comp rocker WILL NOT stand up to a roller. Its junk!


    Compare the OPs rocker to the current "gold" Comp Cams rocker they sell today. MMMMmmm 15 hrs running. But when were they bought? Old shelf stock?


    Wonder how long Comp sold that particular rocker. I've never seen them before. Maybe a reason they gave that particular rocker design up.
    Just another reason to NEVER buy anything Comp.

    Are you at the limit for stud rockers? If you were spinning it anymore than 6300 I'd say a definite yes.
    Are you running a stud gurdle?

    .800 lift and 6300Rs? How big is this thing? 598?



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    Last edited by gn7; 09-03-2012 at 06:51 PM.

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    steelcomp was here
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    The kick tail was a Crane patent design 'till Crane was sold and lost the patent. Then a number of rocker manufacturers jumped on the design, Comp being one of them. It's hard to say what rocker you have there...could be a chinese knockoff, but then...the real Comp rocker could be called the same thing. I can't say for sure, but I think they are made overseas.
    .800" lift is pushing a stud mount rocker, but there are rockers that should handle it. I would most certainly be running a girdle, but if you're switching to shafts, then it's a moot point.
    Curious...what "method" are you using to determin pushrod length and rocker geometry?

    Edit to add: I see now that you never said it was a Comp rocker. Now I KNOW it's a Chinese knockoff. ProComp, maybe?
    Last edited by scott foxwell; 09-03-2012 at 07:06 PM.
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    gn7
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    Quote Originally Posted by steelcomp View Post

    Edit to add: I see now that you never said it was a Comp rocker. Now I KNOW it's a Chinese knockoff. ProComp, maybe?
    Didn't notice that myself. Lately it seems everybody is etching their their name on rockers just for this reason. They don't appear to be ProComps, and definitely not Proform. But I have never seen that particular rocker.

    You may be on the edge of needing a shaft system, but your way past the point of a rocker of an unknown material from an unknown manufacture!!!!



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  9. #7
    Senior Member kidd bill's Avatar
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    Sorry the rocker is a comp, It also has a girdle. the engine is a 582 inch short deck with a dart 360 head and 15 to 1. It turns an A impellor 6300, soon Ill be switching it out for something a bit smaller.
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    Senior Member PCE680's Avatar
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    Quote Originally Posted by kidd bill View Post
    Sorry the rocker is a comp, It also has a girdle. the engine is a 582 inch short deck with a dart 360 head and 15 to 1. It turns an A impellor 6300, soon Ill be switching it out for something a bit smaller.
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    With .800 lift,Jessel or T&D shaft rockers are the only way to go.Everything else is JUNK.

  11. #9
    gn7
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    Quote Originally Posted by kidd bill View Post
    Sorry the rocker is a comp, It also has a girdle. the engine is a 582 inch short deck with a dart 360 head and 15 to 1. It turns an A impellor 6300, soon Ill be switching it out for something a bit smaller.
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    Well that clears up alot, but it fixes nothing.

    I don't mind saying it kidd, but I don't like that rocker. And something tells me, neither did Comp Cams. Never seen that particular rocker. Must have had one very short life span in their lineup. Too much like their red rocker for my tastes. And their red rocker is pure junk.

    You can try to see if Comp will warranty the rocker. Some of their "gold" rockers do have a lifetime warranty. Not sure that particular rocker does. And if it broke in 15 hrs, you have to wonder how long the others will last. Who knows, maybe they will "comp"( you a whole new set of the latest version. Because that IS NOT it!

    If you decide to stick to a stud rocker, I'd consider Isky's, Cranes wide body or Scorpion's Marine Endurance series.



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    Quote Originally Posted by gn7 View Post
    Didn't notice that myself. Lately it seems everybody is etching their their name on rockers just for this reason. They don't appear to be ProComps, and definitely not Proform. But I have never seen that particular rocker.

    You may be on the edge of needing a shaft system, but your way past the point of a rocker of an unknown material from an unknown manufacture!!!!
    been running crane golds for a lot of years. last several, with just a tad over .800. . several years ago, one of the 20 year old golds broke. being in a hurry, i replaced 'em all with new one's. no problems at all since the replacement.
    no question, quality shaftys would be cool. but there's cost involved. of course, shaftys never break...

  13. #11
    Senior Member kidd bill's Avatar
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    Looking at where it broke is kinda boggling to me though, you would think it would break in the thinner part but I guess where it did would be where the most leverage would be applied at. I had problems finding that rocker too but wanna say they were purchased 4 years ago or so. I did read somewhere that they did have some problems like mine but were with the ls series of engines. Im hoping they will do something for me cause it sucks trying to sell 15 rockers. So moving on to shaft setups does anyone know if machining of the pedestals are required with the T&Ds on a Dart 360 head?

  14. #12
    gn7
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    Quote Originally Posted by bp298 View Post
    been running crane golds for a lot of years. last several, with just a tad over .800. . several years ago, one of the 20 year old golds broke. being in a hurry, i replaced 'em all with new one's. no problems at all since the replacement.
    no question, quality shaftys would be cool. but there's cost involved. of course, shaftys never break...
    No doubt that the Cranes are a proven rocker. I only suggested the Crane wide bodies because they are out there NOW. They haven't always. I figure if he is using this thing a play boat, (hard to rack up 15 hrs on a drag boat) the extra width might be beneficial.
    Personally, if it was me and it wasn't a race deal, or spinning any more Rs than that, I'd be looking at Crower SS if I was running a stud rocker on a .800 roller.



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  15. #13
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    As impractical as it is it is a play boat, I hooked up the hour meter to the ignition so the 15 hours has been put on since original starting at home and about 8 or so lake trips. Eventually I will be changing the impellor and turning it a bit higher. Im pretty sure I got lucky when this thing let go and dont think I wanna chance it with another stud mount setup.

  16. #14
    steelcomp was here
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    Quote Originally Posted by kidd bill View Post
    Sorry the rocker is a comp, It also has a girdle. the engine is a 582 inch short deck with a dart 360 head and 15 to 1. It turns an A impellor 6300, soon Ill be switching it out for something a bit smaller.
    Click image for larger version. 

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    Who did you buy them from? I'm not convinced it's not a copy.
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