breather tube to exhaust

Steve Melton · #1 03-28-2015, 02:58 PM

fwiw, I used a automotive water line hose (6 inch) to extend the breather tube onto the exhaust pipe. the breather tube burns to contour against the pipe. coldest temperatures flown -27C at high altitude and -20C at low altitude. no other holes in vent piping. this is only a data point and I fully support an additional hole in the vent pipe if you feel the need.

upper vent piping silicone elbow is holding up well.

Infidel · #2 03-28-2015, 10:08 PM

At the end of the hose above the exhaust, I inserted an 8" piece of copper tubing. Not sure if it makes any difference but my process of thinking is; the copper tubing will conduct heat from the exhaust, lessening the chances of a freeze-up blockage. I previously had a whistle slot but it was making an oily mess.

dongor2 · #3 04-06-2015, 07:28 AM

I see your hose going to the exhaust pipe at the firewall and was curious as to why you would dump oil vapor right on hot exhaust?

Mel · #4 04-06-2015, 08:15 AM

Quote:

Originally Posted by dongor2

I see your hose going to the exhaust pipe at the firewall and was curious as to why you would dump oil vapor right on hot exhaust?

This has been pretty much "standard procedure" for many, many years. The hot exhaust pipe tends to "burn off" the oil residue keeping the belly of the aircraft a bit cleaner.

TS Flightlines · #5 04-06-2015, 09:37 AM

The liner of automotive heater hose doesnt like oil and oil vapors too much. Yep-makes a nice install because of the pre-molded bends. Its pretty inexpensive. If I wee going to do that install, I'd buy several of them and change them yearly at conditional time.
There are other alternatives-----

Tom

dongor2 · #6 04-06-2015, 01:04 PM

I was thinking the rubber hose, the oil and the flow of air leaking around the baffles could ignite with the temperature of the exhaust pipe and then the hose and oil would be fuel for combustion? I noticed the hose in the pictures is touching the E pipe and had "burned to contour". Just sayin.... I recently helped a guy with his -4 and this same hose had become perforated the entire length from oil contamination and was wet to the touch. I purchased some 5/8" AEROQUIP Blue hose to retro fit, its rated for gasoline and oil, should last a long time. Maybe one of the engineers here could calculate the flash point temperature the hose would need, soaked in oil, and compare to exhaust temp that far from the head and give us a thumbs up or down.

Steve Melton · #7 04-06-2015, 05:03 PM

it would be good to have an exterior exhaust pipe temp survey. lead melts at 620F. there are lead deposits inside the exhaust pipe.

automotive related autoignition temperatures. maybe someone can find autoignition temp for Phillips 20/50 XC.
http://depts.washington.edu/vehfire/...sults.html#oil

Toobuilder · #8 04-06-2015, 10:03 PM

Here's what I came up with:

A short piece of tube with a leg welded on. Just clamps to the exhaust with a hose clamp. Works great

dongor2 · #9 04-07-2015, 08:42 PM

Quote:

Originally Posted by Toobuilder

Here's what I came up with:

A short piece of tube with a leg welded on. Just clamps to the exhaust with a hose clamp. Works great

Now that's using your noggin.

Toobuilder · #10 04-07-2015, 10:09 PM

I've spoken of it before, but here's a picture of the other end:

I fabricated a 45 degree fitting on the engine (angled up) and added this automotive valve cover breather with a short rubber coupler. My oil consumption has dropped dramatically compared to the standard overboard dump that came on the engine from the factory.