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bountyhunter

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any one have any idea why my pushrods are bent after most races.... one race i broke a rocker and i belive its the reason i bent several push rods on one side but every time i race now i find one push rod on either side thats bent..... is it cause from bad rockers? over reving? any ideas. it doesnt mess up the lifters or any thing. i just pull the bent one out and replace it and it runs like a champ for about 25 to 30 laps then it happens again but in a differ rocker. any ideas?

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How much lift and what type of rockers? Long slot or stock?

 

Some "lightweight" pushrods just don't have the wall thickness to stand up to racing revs. If your rockers aren't causing the interference, you might consider changing to a heavier wall set of pushrods.

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  • 4 weeks later...

I had essentially the same problem on a high performance street motor, after long periods at high rpm all kinds of nastiness was happening in the valve train. We ended up blue printing the valvetrain and the pushrods where .010 too long because of decking the heads. I would assume you have done this but if not it isnt that bad, most speed shops sell adjustable push rods and SBC pushrod length checker. My first setup was cat roller tips with stock pushrods, then comp rollers with stock pushrods, broke all kinds of stuff both times. Ended up with long slot stamped steel rockers, good crane chrome moly pushrods, arp studs and "Z28" style spings and have gone three years of abuse with not a single issue, drag racing, autocrossing, towing and just about everything else. Hope it helps.

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An easy and visual method to check for the correct pushrod length for roller rocker arms is to:

 

Use a paint marking pen to paint across the tips of the valve stems (e.g. intake and exhaust for cylinder #1). Assemble the rocker arms and set the proper valve lash. Rotate engine a couple of times by hand. Then remove the rockers and look at the rubbing pattern on the tips of the valve stems. If the pattern is centered on the tip of the valve, then your pushrod length(s) is correct.

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  • 2 weeks later...

thanks for all info. havent checked it yet cause of medical problems but i think the medical is finally done. apperently the doctor didnt fix the problem the first time so i was a repeat customer. but fine now and fixen to get back to work on that car. the heads i will have to check cause i dont know what they are milled too but i do know the cam is a 480 lift. and the rockers and rods r stock. thats probly the whole problem. just needs to hold to geater for the turky shootout then we will build a new motor so i will know exactly what i have. thanks for the info....

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  • 1 month later...

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