Re: Restrictors in the oil passages

[Simon Favre <simon@domain.elided>]

This one is also new to me. I don't think highly of it. There was a VERY
good analysis of engine lubrication in a recent issue of Sports Car (the
SCCA national rag, not the Euro auto rag). In this article, a racer with
a considerable background in Mechanical Engineering analyzed why he kept
getting a specific bearing failure running a motor at 8000+ RPM. The 
culprit in his case turned out to be a very curious consequence of the
physics. It turns out that the centrifugal force acting on the oil in
the crank passages caused the oil pressure at the rod bearings to go up
and the oil pressure at the mains to go down! He was having failure on
one main bearing quite consistently. His conclusion was that it was oil
starvation at this main caused by having to feed the nearby rod bearings
which started sucking oil out of the main faster at high RPM. His system
was a typical racing dry sump with a pressure limit valve. 

The author then went on to analyze lubrication systems in great detail.
I'll have to dig it up to summarize more. I think one of his conclusions
was that fitting a high volume oil pump didn't help if you were running
at the max pressure allowed by the standard limit valve (assuming WOT).
In his case, he had to raise the pressure in the system to accomodate
the pressure loss at the mains running at redline. There was no mention
of restricting oil flow to the head. I think he did more work on the
block to balance the flow to the mains.

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