Re: engine 'breather' systems

["Paul Irvine" <pi@xxxxxxx>]

Peter Kemos wrote:

I do not find this to be particularly elegant however, since it clutters
up the engine compartment and has hoses running all over the place.  The
function seems contrary as well; on the one hand oil is expelled and
re-routed back to the sump, otoh air is drawn into the separator from
the air box, due I suppose to engine vacuum, but then I'm told the
device allows built up pressure from blow-by or whatever to escape as
well.  So what is it, is it sucking or blowing? (yes, I know, no
shortage of cheap jokes there.... ;)

Sooo, 1) what does the separator really do?
      2) what are the pro's / con's of the oil filler cap
         breather and/or IAP's filter assembly?
      3) where is the hose from the oil filler cap breather routed?
      4) what's a guy to do?

Peter - The oil separator is basically the same thing as a PCV which stands
for Positive Crankcase Ventilation. In the old days the crankcase was just
vented to the atmosphere normally with a tube that just stuck down in the
open air so that any oil vapors that did collect would just drip out onto
the road. The idea of PCV is that you draw those oil vapors in through the
intake and burn them rather than release them to the atmosphere.

The problem with the SPICA oil separator is that it isn't a replaceable
filter element, it looks like it requires no maintenance and rarely gets
any. Eventually the collector screen or return to sump line gets plugged up
and you start sucking oil into your air cleaner box. The solution is to wash
the thing out in solvent or gas once a year or so and also check that the
return line is not plugged.

In your case, since you want to get rid of it completely... I don't know
about the IAP filter assembly or oil filler cap breather. It doesn't seem
that you would need that since the original breather tube on the right front
of the cam cover serves that purpose. If nothing else you could just run a
hose from that straight down and plug off the intake connections at the air
box and idle air separator.

Paul Irvine  - Antioch CA
72 Spider - 79 Sprint Veloce - 82 GTV6
- ---------------------------------------------
Project Alfa - http://www.crl.com/~pi/project
E-Mail - mailto:pi@domain.elided

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