Rocker failure
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Rocker failure

  1. #1
    031 RIVER4FUN's Avatar
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    Default Rocker failure



    Scorpion rockers. Lost #3 ex. driving to the CP regatta on Friday. Got towed home, put on a spare, drove all the way back [6 miles] then home another 6 miles. Drove back up Sat morn, started to rattle as I was pulling in to park. Towed it home & found #5 ex. and #7 intake broken. All of them on the right bank look O.K. This is the 3rd season on them with several 7000 rpm passes at the track. Fatigue? Going to shaft rockers like I should have done before
    I may be growing older, but I refuse to grow up!

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    Senior Member HBInHeat's Avatar
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    Buy american

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    gn7
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    Sorry to see your weekend was bummed out like that.
    One of the biggest problems with roller rockers is the diameter of the trunnion. The Isky, and Crower SS trunnion is much bigger and I have never broken one. All the others pretty much have the same diameter trunnion. Even Cranes. Never seen a Comp Cams SS, or Pro magnum to know. They may be bigger.
    When you pop a 7/16 hole in that size trunnion, there is nothing left of it. SBC rockers with 3/8 studs have the same trunnion diameter. Usually dealing with less spring pressure. go figure.
    I hate the damn things to start because stud rockers are like little freekn jack hammers. Imagine running you lash in the slop of the bearing of a shaft rocker. Not in the adjuster and pushrod. In the slop of the bearing of the rocker. Its not much different with a stud setup. You can't lift and lower a shaft rocker. You have to rotate it. A stud rocker will slide up and down the stud like a sloppy bearinng in a shaft rocker. You let the lash open just a taste too much, and allow the lifter to get on the cams flank before the lash is taken up, and Wham. Tight lash cams just make it more critical too.
    STUD ROCKERS JUST SUCK!
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  5. #4
    gn7
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    Quote Originally Posted by HBInHeat View Post
    Buy american
    Where do you figure those where made? The south of France?
    Think that has never happened to a Crane?
    A Comp Cams? don't make me laugh on that one. Seen 4 break in the first 1/2 hour in the 300 mile enduro on year. All made here. No, not me. I don't buy Comps stuff and I hate lawyers.
    Last edited by gn7; 08-14-2012 at 06:22 PM.
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    Senior Member EVILFORCE's Avatar
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    That sucks. I have used 10-12 sets in the last couple of years on my motors and customers motors. No failures yet. As Bob said, oh by the way Bob you talk to much, that big of a hole is for sure a weak link. I thought they would be better. Has anyone else had problems with them?









    Just kidding Bob.
    No Fool Like A Old Fool is there?

  7. #6
    gn7
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    Quote Originally Posted by EVILFORCE View Post
    That sucks. Has anyone else had problems with them?









    Just kidding Bob.
    haven't heard of any undue problems with Scorpion rockers. Probably as good as any aluminum rocker out there outside of maybe Crower and Isky.
    In my opinion, there is a limit to what you can expect from a stud rocker. Multiple 7000 plus runs sounds like the thing is some camshaft in it. Probably in shaft rocker territiory.

    You're right, I think I am going to shorten the majority of my posts to Mmmmmmm
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  8. #7
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    Default Call Clay Smith Cams

    I know my rockers on a few motors have been through some violent stuff over the years with a lot of hard miles and not once has one failed or shows signs of any issues... Their a little spendy compared to what you`ll see in a summit catalog but you get what you pay for... George can mix ratios for you as well if you or he thinks it may help you... Tom

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    Quote Originally Posted by tkriley13 View Post
    I know my rockers on a few motors have been through some violent stuff over the years with a lot of hard miles and not once has one failed or shows signs of any issues... Their a little spendy compared to what you`ll see in a summit catalog but you get what you pay for... George can mix ratios for you as well if you or he thinks it may help you... Tom
    Like GN7 said Trunnion size is everything. Isky and crower ss . Are the best for budject builds. Scorpion is now private labeling isky rockers. They do have some old style big trunnions still left in 1.7 ratio (red color) But I do believe there are non of the blue 1.8 Ratios anymore. Correct me if my colors or wrong. But the crower SS is still a great choice!

    Buy the time you buy the good budget rocker and the stud gurdle and everything else. You might as well spend the few extra bucks and go with a shaft mount system!


    Nic
    Last edited by nicwoods6; 08-14-2012 at 09:52 PM.

  10. #9
    gn7
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    Quote Originally Posted by nicwoods6 View Post
    Like GN7 said Trunnion size is everything. Isky and crower ss . Are the best for budject builds. Scorpion is now private labeling isky rockers. They do have some old style big trunnions still left in 1.7 ratio (red color) But I do believe there are non of the blue 1.8 Ratios anymore. Correct me if my colors or wrong. But the crower SS is still a great choice!

    Buy the time you buy the good budget rocker and the stud gurdle and everything else. You might as well spend the few extra bucks and go with a shaft mount system!


    Nic
    I think the Isky blue are the 1.7 and the purplish red are the 1.8 Anodize is iffy inconsistent stuff anyway.
    Yep, you have to add it ALL up, and it makes it a little easier to make the RIGHT choice. Specially with a agressive roller. It Seems less painful when you buy parts here and there, but in the end, it adds up and its not that much more.
    Problem is, the head manufactures need to stop including the stuff in assmebled heads. Now you tell your self you only need rockers, and maybe a gurdle later.
    maybe another reason I never buy assembled heads. Hate throw stuff in the trash
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    Senior Member lbhsbz's Avatar
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    I had a set of crane golds and some comp aluminum ones....the comp trunions were about 2/3 the diameter of the cranes. My cranes trunions were kinda beat, so I machined a flat on the other side and flipped 'em over to load the good side...found new bearings somewhere...can't remember where, and ran the hell out of 'em. I couldn't find much with trunions the size of my old ass cranes.
    GN7: "If you were to have ever had two brain cells you could rub together and make heat, you be dangerous"

  12. #11
    Foxwell Motorsports
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    Scorpion rates those rockers at 900lbs and .900 lift. I'll go out on a limb and say it wasn't the rocker's fault. Very seldom is a (decnet quality) broken rocker, the rocker's fault.
    Last edited by steelcomp; 08-14-2012 at 10:33 PM.
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  13. #12
    gn7
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    Letting the lash get away will take out the best stud rocker, or even shaft rocker quick. That nice smooth clearance ramp becomes a vicious wall real quick if the lash open up. And you never knew it because the rocker is in pieces and the forensics are kind of hard to prove after that.
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  14. #13
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    Quote Originally Posted by RIVER4FUN View Post


    Scorpion rockers. Lost #3 ex. driving to the CP regatta on Friday. Got towed home, put on a spare, drove all the way back [6 miles] then home another 6 miles. Drove back up Sat morn, started to rattle as I was pulling in to park. Towed it home & found #5 ex. and #7 intake broken. All of them on the right bank look O.K. This is the 3rd season on them with several 7000 rpm passes at the track. Fatigue? Going to shaft rockers like I should have done before
    It almost looks like the rocker on the left had the trunnion upside down.
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  15. #14
    Led
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    Quote Originally Posted by steelcomp View Post
    It almost looks like the rocker on the left had the trunnion upside down.
    thats exactly how I killed a pushrod, roller lifter, and cam......Upside down.... wont do that again.

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