I'm running a welded on -10AN fitting on the chimney to a firewall mounted breather on the autocross car. I've experienced twice now, the chimney clip coming undone while driving the car hard. I'm thinking the SS braided -10AN line is too stiff for the chimney "clip" to overcome any movement in the body and drive train.

Does anyone have any experience with a softer, more flexible AN style hose?

-Aaron

I'd try out some Push-loc hose (+associated fitting). It's rubber, nice and flexible, and inexpensive.

http://www.914world.com/uploads/4281_b1.pdf

I went all in on a push lock style system once and it failed. Granted this was for an oil cooler, but the hose got soft in the heat and oil was pouring out everywhere.

Fragola hose is the best.

I've used Fragola stuff for both oil and water systems and been happy with both price and performance. The brand name Parker Push-loc hose has also worked out pretty well.

Alternatively, fiber-braided hoses are also pretty good in my experience. I've never made them, only purchased from BMRS, but they've always held up well and had a bit more flex.

The Fragola Nylon hose is totally affordable and will use standard AN fittings (which I have a million of). I'll likely try that first. I may also move the breather off the firewall and mount to the back of the motor itself via a stand to keep it isolated.

There is a chance this is also happening because the bale itself has weakened over time. I'm going to try and find another one to test. Mine even with the 914rubber.com thicker gasket doesn't take much effort to clip.

I decided to bend the bale in to a better shape and ghetto up a softer, more flexible hose. 1/2” ID heater hose fits the -10AN fittings surprisingly well.

Click to view attachment

Wrong... Hose is crap. Fittings are crap.

They are not true AN (Army/Navy) mil spec sizes. They are not interchangeable with other correct AN hose. They are smaller ID/OD than the same AN sizes from Aeorquip, Earls, Jeggs, Summit, etc. Use them if you want but make sure that's all you use because nothing else will fit on their proprietary hose size or fittings.

Aaron, that just looks like it will wiggle lose with so little flex.
I would keep a close eye on it, and maybe consider a slightly longer piece of hose to add in some movement?

Seems from what I can see, the oil breather is mounted on a stationary part of the car, and the engine is moving?
that type of movement will loosen up something over time.

I agree. The proof of concept is there though. That heater hose is super soft! If it survives the next event I’ll move to a nylon braided (style) hose and mount a standard, non-return breather/catch can to the stand off you can see in the picture.

it will get really soft and squishy when you are at the event...
Dont touch it or you may walk home...lol

I ended up putting the oil breather box on a bolt on the motor.
then, everything moved together.
I struggled with the head breathers and main breather until I moved the box...then all the wiggling stopped and things worked perfectly.

And yah, that tubing...it won't last if its what I think it is.
I tried that too