Thanks to everyone for their excellent advice on air/oil separators for an IO-550N engine.  Looks like people’s experiences range from very little oil venting so no air/oil separator needed to they are absolutely needed.  It looked like the c.g. of experiences is that they do at least help minimize the oil put overboard on the belly of airplanes.  We already have an Andair air/oil separator and oil catch cup so we are going to install them.  We’re not going to put the collected oil back in the engine, though, given the reported quality of it with water and combustion products in it.

Thanks again for everyone’s experience and advice!

Valin & Allyson Thorn

Legacy Project

Boulder, Colorado

Hey LML gang, we’re finalizing our firewall layout and the Lancair Legacy manual says the Continental IO-550 engine does not require an air/oil separator.  Still, I’ve noticed some IO-550’s flying with them and some without.  Would appreciate advice from the community on whether we should install one…

Thanks,

Valin Thorn

Legacy Project

Boulder, Colorado