Re: COZY: Oil Separator

I don’t think there is much chance of data supporting it.  Those who object to sump return are in the main concerned with the return of acids to the sump.  In principle, I suppose that acid vapours may be cooled and condense and be returned in some circumstances.  I think it unlikely to be a significant issue, given that aircraft engines usually spend long periods with the oil more than hot enough to evaporate acids from blow-by - at worst, it will take a little longer.

Crankcase ventilation in piston engined aircraft is generally, well, if not antiquated, certainly old fashioned.  A modern crankcase ventilation system, deliberately introducing filtered air into the crankcase and ventilating by a combined PCV valve/oil separator, returning the residue to the sump is vastly superior in reducing acid in the oil - even if vented into the induction system instead of directly overboard.  The PCV/Separator in suitable sizes can be obtained as a BMW spare part for their larger petrol engines.  Whistle slots and slits in case of icing still need consideration.

Paul Saccani

On 16 Jun 2021, at 08:22, Marc J. Zeitlin <marc_zeitlin@...> wrote:

vance atkinson wrote:

 Try the Cozy Girrls... they make a really nice one....

I have theirs as well - probably their beta unit :-).
I would NOT plumb it so the oil goes back into the sump.  That is some nasty stuff. Instead I took one of my wife's Revlon bottles and plumbed the return into it.

I do the same - I've got a collection bottle that I empty maybe once/year or so. However, I have a hard time believing that routing the stuff the unit collects back into the sump is a problem - it just came OUT of the sump, so it's already been in there. No? I just had no handy place to dump it back in, and I didn't feel like modifying the oil filler, or a return line, or the exhaust pipe - the collection bottle was just the easiest solution.

I'd be interested in seeing some objective data indicating that running the separator residue back into the sump is a bad idea, and why...

Marc J. Zeitlin                      marc_zeitlin@...
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