[Fot] Crank case evacuator question

[Robert M. Lang]

Hi,

I don't know the full theory on this stuff, but the key here is that you 
have _pressure differential_ between the crank case (or valvetrain) and 
the catch tank. In order to keep oil from blowing out of every crevice on 
the motor, this differential must be negative where you want the oil (or 
vapor) to flow.

So, you don't need a lot of vacuum - you just need lower pressure than 
what's inside the engine.

You can get crazy with all this, but if the goal is to stop leaks and 
stuff, you need "just enough". Two 5/8" hoses is def better than one 1/2" 
hose (which is what the factory used for Federal Emissions cars) - so two 
AN10's would be great.

As far as the "breathing" part, you just need about the same surface area 
of outlet as the hose(s) you are using to vent the valve cover. If you use 
MORE area in the outlet you can't get lower pressure in the catch tank and 
you more or less defeat the purpose OR you need to find a better method to 
reduce the pressure in the catch tank...

My setup works pretty well. Even when I had a broken ring (30% leakdown 
past the rings) the motor didn't leak at all! Surprised me too (when I ran 
the leakdown test).

I like the suggestion of a baffle in the valve cover. That's what the 
factory did (although they also use a screen which is overkill IMHO).

c ya,
rml
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Bob Lang              Triumph TR6!!            |  This space for rent
Former NER Solo Chair                          |
Voice:617-253-7438                             |  Cell: 339-927-4489
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