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Bottom End Stuffs

Anonimo

By Anonimo,
in Engines & Forced Induction

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Anonimo Rookie

Anonimo

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Posted

Crank stuff

Ive noticed that std rb30 cranks are cross drilled. I guess like most production cranks. The common knowledge is that at higher rpms oil has a hard time getting to the big end journal when it has to fight centrifugal forces acting against it. As a result its usually the big ends that go first normally due to insufficient oil supply...which commonly happens in the higher rpm range.

Has anyone come up with any mods (crank or otherwise) to overcome this, whether its a critical issue or not? Or perhaps even thought about it? I am aware that it helps by running higher oil pressure to overcome said forces, but high oil pressure also robs horsepower, creates excess friction and heat to both the oil and bearings. Obviously if a billet crank was being made soley for performance applications it would be a straight-line or straight shoot.

Block stuff

I know there are a few block mods to do to most rb30 bottom ends to allow them to handle more power for racing/performance situations.. Like drilling out the main feeds to 7mm and the bearing shells to suit. Some even goto the length of grooving the block(not caps/girdle) so you can run gtr bearings with the multiple oil holes on the top shell.

Has anyone thought about or tried perhaps 360 degree grooves. So both block and cap have oil flow around the bearing? You would have to mod the bearing with oil holes so you could take advantage of this, but i would think it would allow for a constant oil feed to the mains/big end.

Obviously with all these extra passages for oil to flow pressure would drop and you would need to either up the pressure or get a higher flowing pump to provide enough extra oil for these extra areas.

Anybody have any thoughts/ideas/tip or tricks?

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psi Experienced

psi

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The humble old RB30 is a very durable device. Just look at how many are still driving around on the roads..

What sort of punnishment are you thinking that you are going to apply to your engine?

In standard form, with standard oil pump, they are prone to some oil issues at hi revs only.

But from what I have found, the problem lies totally in the oil pump itself.

The pump does not like and cannot handle prolonged hi revs. We have had cracked pump housings and such, but never had any oil issues anywhere else with the stock RB30 configuration.

Unless your building a monster engine to do insane revs, it seems to as if your trying to fix an issue that does not yet exist for this engine.

in this part of the forum, look up 'RIPS', he has done some very crazy things with the RB30.

If anybody has struck such issues, it would be him! and he would know how to fix them!

Anonimo Rookie

Anonimo

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Posted

This is all in reference to high end pure race motors...not road cars. Drag, Drift and circuit cars only. Not including peoples road cars that see track work either.

Yeh ive seen the RIPS stuff and followed some of his/their work. Very good stuff. I agree with you bubba. He seems like he holds quite a few secrets close to his chest! But with good reason. It would be nice to know if there are some things he does that he hasnt eluded to publicly. Especially when you get up in the high horsepower and big rpm areas!

Everyone i know who races hybrids have to keep revs low and always seem to have bottom end issues. Often seen in engines pushing 600hp+ and see anything over 7500rpm.

spannerx Contributor

spannerx

Posted
Posted

The cranck my be standard but im sure it will be all about the clearences, stud size, clamping torques, oil gallery enlargments including bearing shells, i wonder how much nascar engine spec is applied to a meir nissan 6 ?

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