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Breaking Roller Rockers??????

Breaking Roller Rockers??????

Old 11-16-2006, 08:45 PM
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Default Breaking Roller Rockers??????

Guys we are breaking roller rockers on the race boat, 510 BBC with Mega Blower, about 950 HP. Dont run more than 6000 rpm and have just split another set of rockers. What type should i use. Thanks. Jas
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Old 11-16-2006, 09:23 PM
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Default Re: Breaking Roller Rockers??????

I assume you are using aluminum rollers? If so, you might switch to stainless steel rollers. A lot stronger. Comp cams and Crower make a set. Comp part number is 1120-16 for a set of 16.
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Old 11-16-2006, 09:32 PM
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Default Re: Breaking Roller Rockers??????

billet aluminum rockers ought not break. you sure they aren't bending and then losing the tip roller? Show us a pic.
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Old 11-16-2006, 11:57 PM
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Default Re: Breaking Roller Rockers??????

I don't know what brand your running but IF you buy comp magnum steel rockers to replace them THROW the nuts that come with them away,they caused me MUCH agravation. I'm running around 190 seat and 460 at peak open and turn up to 6000 rpm's on my motor,no rockers have broke yet,I also used the arp pro studs. I'm converting to T&D shaft style this winter to eliminate any potential problems,Smitty
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Old 11-17-2006, 02:41 AM
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Default Re: Breaking Roller Rockers??????

They are stainless. Look like comp cams but i think are not. Have about 200 on the seat and run 6400 rpm. This is the second set. Split where the pushrod sits in the cup. Drove the pushrod right through the the rocker and smacked the stud gidle. Have top arp studs. This is odd. I never broke a rocker in years. No heat marks or blueing. Maybe we need Jesel shaft mounts. Or maybe aluminum will be more forgiving. Cost us two races now!!!
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Old 11-17-2006, 03:07 AM
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Thumbs up Re: Breaking Roller Rockers??????

Run the Crower arms.... Much less weight at the valve stem especially after doing the math was everything else totally on point ? We are constantly being humbled with all of this stuff. When we think we know it all, that"s when something unforseen comes up and bites us in the @ss,,.BBB
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Old 11-17-2006, 06:39 AM
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Default Re: Breaking Roller Rockers??????

Valve floating issue ? Are we running the correct springs and are they installed correctly ? Geometry correct ? Rockers touching retainers ?

Are these HR or Solid Roller ?

Should you be running a shaft rocker for your application ?

Last edited by SB; 11-17-2006 at 06:41 AM.
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Old 11-17-2006, 08:52 AM
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Default Re: Breaking Roller Rockers??????

I have always been told that the weakest link in a Big Block Chevy is the valve train. They cost more, but the shaft mount style rockers are much more reliable/stable vs the very old stud mount design.
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Old 11-17-2006, 07:42 PM
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Default Re: Breaking Roller Rockers??????

not that i havent blown up a lot of sheet but shaft mount rockers jesel all the way it is the only thing in my motor that has not pucked up yet
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Old 11-17-2006, 09:55 PM
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Default Re: Breaking Roller Rockers??????

How close you running to coilbind? You checked your piston to valve clearance? Retainer locks got enough clearance to the seals/guides?

Sounds like an impact issue. Like what you get with too much lash, a collapsing hydraulic lifter, valve float and the "snap" you get when the pushrod ball rattles off the socket.

You got plenty of guide clearance? heat may be causing the valve to float due to stem drag.

I think your rocker breakage is a SYMPTOM, and not the problem maybe.
mc
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