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Rocker arm?

General engine tech -- Drag Racing to Circle Track

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rebelyell
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Re: Rocker arm?

Post by rebelyell »

rickb33x
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Re: Rocker arm?

Post by rickb33x »

not wissota rules but thats an interesting read.
cgarb
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Re: Rocker arm?

Post by cgarb »

Can you use the moroso rocker arm oil deflector? That will #1 keep more oil on the rockers and the valve springs and #2 if you drill all the studs through and use long set screws to attach the deflector, sort of an undercover stud girdle.
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Re: Rocker arm?

Post by V12MECH »

Interesting idea about using valve grind compound to lap ball against rocker seat, maybe use cam moly lube instead to establish wear pattern and try to replicate rocker arc at same time while polishing.
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Re: Rocker arm?

Post by panic »

Are banana grooves still of use?
rebelyell
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Re: Rocker arm?

Post by rebelyell »

JMO. Seems your rules tightly restrict valve spring; looks a lot like "Z28" aka RV943 or maybe +100 taller RV1943 spring specs. If so, No girdle ain't much to fret about. Seems springs like that'll also self-limit cam. YMMV
rebelyell
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Re: Rocker arm?

Post by rebelyell »

V12MECH wrote: Sat Oct 31, 2020 7:01 pm Interesting idea about using valve grind compound to lap ball against rocker seat, maybe use cam moly lube instead to establish wear pattern and try to replicate rocker arc at same time while polishing.
Idea not original to me. I think the moly lube (or any lube) will only serve to prevent wearing-in a pattern; use an fine abrasive (e.g. lapping cpd) to mate & seat the surfaces then clean & assemble on heads w/ some moly lube or CMD #3 lube.

After lapping, suppose you might polish w/ a finer rouge cpd. Or, just send em out for REM polish.
rickb33x
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Re: Rocker arm?

Post by rickb33x »

Have used 1.265 springs and tech never complained. Valve covers with oil sprayers can be used. I've never had issues with the grooved pivot ball.
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Re: Rocker arm?

Post by jsgarage »

RickB33, the stress on a valvetrain will be proportional to rocker arm ratio. Pushrod strength is unaffected by the very small differences in ideal length. And this is done only to make 100.00% sure the cam opens the valve to its design height. As for roller tips on rocker arms, they may- possibly- reduce oil heating a bit while making optimum valve adjusting more difficult. 90+% of the desired low friction comes from the roller trunnions.

If you'd like to be a pit-lawyer and likely force an emergency rule change, know that in the late '60s Ford used their usual sled-pivot stamped steel rockers that had half-circle bottoms to help guide the rockers & pushrods on studs. Those precision stamped half circles coincidentally fit small roller bearings with special stud-mount fulcrums that Ford sold, to produce full adjustable roller-bearing-fulcrum stamped steel rocker arms- all with factory part numbers. High ratio, too: 1.72:1. No power advantage but lowered frictional oil heating enough that sometimes no oil cooler was needed. Used on racing Boss 302s and NASCAR 351 Clevelands.
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