Engine Breather Tube Routing

[elliotblock]

Hello all,

I searched for “breather” and came up with this thread and some others. I read them all.

I have some oil on the belly after each flight and compressions are good.

Some of the oil is undoubtedly coming from the breather and some is coming from old gaskets which need replacement.

I think I’m going to work on the breather first.

First, I’d like to find a 633182 breather elbow if anyone has one laying around that they’d sell.

Second, my breather has the original routing (not over the top) but it outputs directly into the cowling; if I remember right its output sits about 4-6” above the bottom of the cowling. I think it should output just below the bottom of the cowling with an angled cut which faces forward.

Does anyone have opinions on this?

Thanks!
Elliot

[8455]

Elliot,

No idea on overall routing, but I think you need the slant cut on the bottom facing back towards tail. Seems to me like a cut facing forward is likely to pressurize your breather tube and crankcase, exactly opposite of what you want your breather tube doing.

[elliotblock]

Thanks for the input!

Elliot

[6643]

First, I’d like to find a 633182 breather elbow if anyone has one laying around that they’d sell.

Make one.

extended breather.jpg (21.58 KiB) Viewed 4273 times

[ericbrabec]

Did any one use an Oil separator on a O-200 install?
If yes I would be curious to see the install and if it worked good!
Thanks
Eric

[a64pilot]

First, I’d like to find a 633182 breather elbow if anyone has one laying around that they’d sell.

Make one.


extended breather.jpg

What did you use for tubing, it looks like SS? Did you machine out the fitting? Silver solder or tig or what?

[8342]

Neal Wrights technical article in this forum tells how to make the breather elbow.

Rick

[2356]

I silver soldered a piece of brass tubing in mine.

[7392]

To 2356

Re: BREATHER TUBE ELBOW

I also intend to silver solder a piece of brass tubing into my current breather tube
this weekend. What length of tubing worked for you? My mechanic said he couldn't locate the
Neal Wright article.

Thank you

Larry Surratt
1946 C-140
#89011
Serial # 8015

[a64pilot]

I’ve not read the article lately, but if memory serves it doesn’t specify a tube diameter internal or external, does I believe mention machining out the fitting, but doesn’t give specifications. It gives I think a length of 2 3/4” again going off of memory and I assume that is a length that extends from the fitting and not a total length? So we need maybe a tube 1/2’ or so longer?
Now I know that it’s possible to have too small an internal diameter and that restrict airflow and raise crankcase pressures more than desirable, so I was wanting if possible a tubing recommendation. Thin walled tubing would I assume be best as that would give you the largest internal diameter without having to machine out too much meat on the fitting. ButI done know what the internal diameter of the factory part is, that might be useful information.

I reduced blow by oil mist on my IO-540 by manufacturing an air oil separator by copying the M-20 design, it’s just a labyrinth really. But my zero time since overhaul IO-540 consumed a quart every ten hours with new Millenium cylinders, which was exactly what it consumed at 1800 hours.

Not that I have had a whole lot of airplanes, but I’ve been around a few, and they all had greasy bellies, and all consumed oil.

I think we may can reduce the greasy belly some, but maybe it’s really a normal operating condition of engine designs dating back almost 100 years?