Valin and Allyson,

We are running a Andair separator with a catch tank to measure the blow-by between oil changes at every 25 hours.  I want to compare the volume of blow-by from change to change and keep the acid/moisture/oil goop from returning to the engine.  Our 419 hour Barrett IO 550-N with stock compression averages about 2 oz. (oil consumption aprox. 1 qt in 15+ hours).   An additional benefit is a cleaner belly.  One thing I would change is the location of the Separator.  It can be mounted on top of the aluminum baffling in the left rear corner next to the oil cooler.  The advantage of this location is it is on the cool side of the baffling for better condensation.  I don’t recall if the Legacy Manual recommends a Ice Slot but  a vertical ¼” wide x 1” long slot cut about 6” above the outlet is a good idea.  I positioned the vent outlet just above the exhaust to vaporize anything that gets past the separator drain.  We have a 8 quart sump and use 8 quarts with a filter change. 

Steve Colwell  Legacy 550 RG