Can Someone identify what this extra oil return line outlet is for?

WenEng · #1 01-18-2009, 08:50 PM

I bought a mid time IO360B1E off a Piper Arrow for my RV6A. Going over it, I noticed this extra oil line welded onto the normal oil return line from left rear cylinder head to the sump. I have no idea what purpose it served. Anyone know what this would have been for? I didn't notice it until after I put on a new Superior cold air sump to point the fuel servo horizontal forward rather than backwards like it was on the Arrow.
Thanks.

" target="_blank">http://i614.photobucket.com/albums/t...="0" alt="" />

Mel · #2 01-18-2009, 08:52 PM

Can't see your picture, but from your description, my guess would be that it's a drain-back from an air/oil separator.

WenEng · #3 01-18-2009, 08:57 PM

Mel · #4 01-18-2009, 09:00 PM

I'll stand by my first guess. A return line from air/oil separator.

Rivethead · #5 01-18-2009, 09:40 PM

I do believe Mels right

az_gila · #6 01-18-2009, 11:51 PM

Quote:

Originally Posted by Mel

I'll stand by my first guess. A return line from air/oil separator.

...I wonder which Piper Arrow STC allowed a hose to hang off a welded joint like that...

osxuser · #7 01-19-2009, 09:48 AM

Not only is Mel right, as usual, but that IS an approved way to route oil back into a Lyc. If you aren't gonna use it for anything, I personally would fab up a new tube.

Wicked Stick · #8 01-19-2009, 10:08 AM

It might be approved, but it sure looks like a cheesy way to do it.

It is kind of amazing some of the things that get approved and other common sense things do not. Must be the law of averages at work...

WenEng · #9 01-19-2009, 02:33 PM

It is a very substantial weld and for a line returning oil to the sump from an oil/air separator I am comfortable with it and may incorporate it into my oil/air separator when I get that far unless I discover a better way beforehand. It sure is a simple task to create a new oil return tube without this added line. Being one of the newer builders here I really appreciate everyone's interest in helping with advice.

aerhed · #10 01-19-2009, 07:32 PM

I've seen lotsa Walker returns like that. For Connies they drill a hole in a rocker cover. It works, too bad the separator itself doesn't work. Separators are usually just a cover-up for bad jug walls. On long flights they often just get overwhelmed. A good lyc. should go at least 15 on a quart. Really good ones can go 25hrs/qt.