Tip: Crankcase Breather Hose

Ironflight · #1 05-19-2011, 06:45 PM

When I was doing an oil change a week or so ago, I discovered that my standard-issue breather hose elbow (from the crankcase fitting to the aluminum tube that runs down the firewall had finally swollen and gotten unacceptably gooey. I tried AE6000 hose (had some sitting here for the RV-3 inverted oil system), but it wouldn?t bend tight enough without kinking. Tom Swearengen from TSFlightlines.com dropped me a note that he might have a solution ? ?? steel-braided hose with a convoluted liner to prevent it from collapsing in a tight turn. I figured that it was that, or go back with another radiator hose that would get gooey again, so we gave it a try. It only took about 9 inches of hose, and I covered the ends with some giant, industrial-strength, adhesive-lined heatshrink, just to dress them a little (and prevent loose, raying stainless wires) ? and it worked great! I don?t know the hose part number, but it I?m pretty happy with it.

Paul

TS Flightlines · #2 05-19-2011, 07:04 PM

post a pic of the other side so I can see your tube!! I have a few ideas on these, depending on space.
Tom

Quote:

Originally Posted by Ironflight

When I was doing an oil change a week or so ago, I discovered that my standard-issue breather hose elbow (from the crankcase fitting to the aluminum tube that runs down the firewall had finally swollen and gotten unacceptably gooey. I tried AE6000 hose (had some sitting here for the RV-3 inverted oil system), but it wouldn?t bend tight enough without kinking. Tom Swearengen from TSFlightlines.com dropped me a note that he might have a solution ? ?? steel-braided hose with a convoluted liner to prevent it from collapsing in a tight turn. I figured that it was that, or go back with another radiator hose that would get gooey again, so we gave it a try. It only took about 9 inches of hose, and I covered the ends with some giant, industrial-strength, adhesive-lined heatshrink, just to dress them a little (and prevent loose, raying stainless wires) ? and it worked great! I don?t know the hose part number, but it I?m pretty happy with it.

Paul

Greg Arehart · #3 05-19-2011, 07:16 PM

Tom,

Let me know what you come up with. I'm looking for something better than the very stiff hose that I have.

greg

TS Flightlines · #4 05-19-2011, 07:37 PM

I actually crimp this hose to fittings, but I'm going to devise something that you can attach in the field. I can secure it with stainless bands, like firesleeve bands, and it looks great, just hard to do in the field. The other problem is the NPT fittings in the accessory case. In order to make a nice looking "crimped" assembly, you really need a male NPT swivel; but then you can get alittle bypass leakage from the internal o'ring. Using a AN816-12D would be ok, except not all guys are using the same stuff, and you may not be able to tighten a AN nut on the adapter. So, another custom situation.
Hose clamps work fine for most situations, if like Paul did, you wrap the ends so the stainless braid doesnet ravel.
This hose is very flexible---can be used for alot of applications, and unlike smoothbore teflon, convoluted it true bore sized, so standard hydraulic fitting stems work well.
I'll work on this a bit.
Tom

TroyBranch · #5 05-20-2011, 06:57 AM

In canada we require to punch a hole in the top of that hose just incase the breather hose exit ever froze up. It has happened to many and blows out the front seal. I am sure you know what happens after that. Everyone seams to fly in cold weather some times no matter where they live. Not a bad practice for all aircraft.

F1Boss · #6 05-20-2011, 07:11 AM

Quote:

Originally Posted by TroyBranch

In canada we require to punch a hole in the top of that hose just incase the breather hose exit ever froze up. It has happened to many and blows out the front seal. I am sure you know what happens after that. Everyone seams to fly in cold weather some times no matter where they live. Not a bad practice for all aircraft.

In the US, we cut a notch in the tube near the exit for the same reason, but we make sure it is in the warm area of the flow. We call 'em whistle slots.

Carry on!
Mark

PS std hose can be used, but you gotta put a spring in the hose to keep it from collapsing. This particular installation looks very sanitary, BTW.

Mike S · #7 05-20-2011, 10:07 AM

This is probably just a optical delusion, but it sure looks like the new stainless hose is either touching, or close enough to touch the motor mount.

Anti chafe protection ????

TS Flightlines · #8 05-20-2011, 11:36 AM

i saw that pic too--might ba an illusion, BUT chafe guard can certainly be done.
Tom

Mike S · #9 05-20-2011, 01:43 PM

Quote:

Originally Posted by TS Flightlines

i saw that pic too--might ba an illusion, BUT chafe guard can certainly be done.
Tom

Knowing Paul, I suspect it is got plenty of clearance.

But, just as a caution for folks looking at this thread, who might get the idea to copy the setup, ........well just wanted to make folks aware of the need to protect stuff from SS braided hoses.

Greg Arehart · #10 05-20-2011, 02:03 PM

If you can find the right size, it would be good to put tygon tubing (plastic stuff from Lowes or similar) over the steel braid for chafe protection. That's what I really like about the Bonaco hoses - Brett encloses them in the tygon for chafe protection.

greg