[6pack] New Engine AUTOpsy

[Robert Lang]

On Tue, 9 Sep 2008, Ruffner, James A *HS wrote:

> Oil pressure is set by a relief valve that is composed of a spring and 
> ball bearing that are inside of a drilling.  This is a separate device, 
> much like that in an OD unit, and is adjustable in some engines.  For 
> these, there is a bolt that presses on one end of the spring, with the 
> ball bearing at the other end of the spring.  As oil pressure rises in 
> the main oil gallery the pressure forces the ball away from the opening, 
> which in turn allows the oil to escape back into the sump.

I actually have quite a bit of experience with the pressure relief 
valve... it turns out that if the valve sticks closed, you get insane oil 
pressure. Like enough to break the oil pressure gauge. If it sticks open, 
you get NO (or very little) oil pressure and the rods complain very soon 
afterward.

I had it stick open once and I wrecked a bearing. I pulled the cap and 
(fortunately) the bearing material had not worn away and the bearing 
didn't stick or spin. I cleaned up the journal and stuck it back together 
(with a new bearing, of course) and ran it that way for 40 or 50 
autocrosses, maybe 5 years and no "issues"

rml
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