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Old 11-11-2007, 07:36 PM
Anthony Anthony is offline
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Join Date: Apr 1999
Location: cleveland, OH
Cobra Make, Engine: CSX4000, 427
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Some thoughts.


Quote:
Originally Posted by PatBuckley
As for the oil pressure, I have always gone with 10 psi per 1000 rpm.
Yes, I have heard that many times too. I've also been told that it is the bearing clearence that truly determines PSI and weight of oil needed, not what the oil pressure gauge says.

Quote:
Originally Posted by PatBuckley
Excessive pressure costs power and you run the risk of breaking things. It takes a lot of twist to generate all that pressure and in any case it's the lubricating properties of the oil that keeps things going not the pressure of the oil.
Absolutely. I've heard about shaft and gear failures, and obviously, the more pressure and flow you generate, the more HP it's going to cost you. But, the higher pressure will likely give higher oil flow, cooling the bearings and other engine components to a greater degree.

What you can't measure is the oil pressure at the rod bearings. I've read somewhere that chamfering only the leading edge on the main journal, and only the trailing edge on the rod journal will significantly increase pressure and flow of oil to the rod bearings, which I have done on my crank.
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