List and Jim: Sorry about the delay but I have tried to send this 3 times.
I will break it into two parts, maybe it will go through. -Elon
The oil coming from the engine is an emulsion. It is aerated with millions
of tiny bubbles caused by all the turbulence the oil sees along it torturous
path of lubricating. That is a very bad thing. You want to pump a pure,
liquid oil to the bearings and not a frothy foam. One of the many design
attributes (and benefit) of a dry sump system is mainly focused on removing
the air from the oil. Look inside of your tank and you will see numerous
baffles that the returning oil will spill on to. The principal uses surface
tension. The idea is to apply the thinnest film of oil as possible over the
largest surface area as possible. The air bubble in the oil film is
released due to weakened film-strength and (hopefully) the oil collects at
the bottom of the tank as a pure liquid to be pumped back to the engine.
Obviously, the tank has to be vented to release all of the entrained air as
well as the crankcase air (even if it is a partial vacuum). Venting the TANK
is NOT venting your engine (as suggested earlier). At least it is not the
same as a vented valve cover.
An article in the most recent Circle Track suggests that a crankcase vacuum
greater than 15" Hg may be responsible for piston pin failures. Pins depend
a lot on the crankcase aeration and it is greatly reduced in a partial
vacuum. CT also suggests the benefit gained with greater than 15" vacuum
does not translate to an equal increase in HP.
-Elon
Jim Webb (snip. . . ) Am I screwing up by venting the tank to atmosphere?
All the tanks I look at seem to have a provision to vent to atmosphere. Even
Weaver_s diagrams of how to set up the systems shows a line from one valve
cover being vented to atmosphere. Why? That would certainly kill crankcase
vacuum. It seems that the goal is to make plenty o_ vacuum in the crankcase,
but with the discharge of the suction side essentially blowing into
atmospheric pressure, am I getting a vacuum break there? Should there be a
check valve?
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