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szicree

Well Known Member
What material is used for the engine breather tube in the FWF kits? I see the drawings call for a short hose elbow and a long run of what I assume to be a rigid tube, but it doesn't specify material. I'm hoping to find what I need at Spruce. Also, does the MAP hose get a restrictor like the oil and fuel pressure lines?
 
Steve,

This is Van's aluminum breather tube. It is swaged on the upper end to accept the rubber elbow that is trimmed by the builder to the required length and then attached to the breather tube with stainless clamps. For my particular installation, I had to slightly alter the bend of the tube so it would locate directly over an exhaust stack. Naturally, YMMV.

The IE VMP INSTALL KIT includes an AN816-4D nipple that is attached to the engine for MAP. The kit also includes a bulkhead restrictor adapter (VA-170) that mates with the included PT .094X.156 LO PRES PVC tubing.

 
gmcjetpilot said:
You can use rubber hose for most of the routing and than transition to metal tube for the last say 6" or so near the exit (to handle the heat near the exhaust).
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Just be careful with the rubber hose - I used a small, formed heater hose to make a turn in my breather line right where it exits the engine. This hose was about a 3/4" or so, high quality Gates hose. After about a year, it was disintegrating a bit, with oil oozing from it and the rubber getting very weak. I found this also on a hose I had linking the MAP line from the engine to the firewall. This line tends to get some oil mist in it as well, and it was sweating a little oil. This hose was an automotive fuel line. There seems to be something more robust about the hose actually sold for breather lines.
 
Great point

AlexPeterson said:
Just be careful with the rubber hose - I used a small, formed heater hose to make a turn in my breather line right where it exits the engine. This hose was about a 3/4" or so, high quality Gates hose. After about a year, it was disintegrating a bit, with oil oozing from it and the rubber getting very weak. I found this also on a hose I had linking the MAP line from the engine to the firewall. This line tends to get some oil mist in it as well, and it was sweating a little oil. This hose was an automotive fuel line. There seems to be something more robust about the hose actually sold for breather lines.
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Yea I had worried about kinks in the soft tube, in the back of my head, but breaking down...I had no idea. Thanks for the tip.

I did not recommend any specific type of hose because I used clear vinyl for both application in the past. It does or could have some susceptibility to being kinked if you make a tight bend. However if you route it smoothly. The clear vinyl has held up nicely. Tygon with that nylon mesh integrated into it is very stout and kink resistant. It should hold up well but than cost might go up over aluminum.

When I did it Van did not have the aluminum tube breather kit (is that part of the FWF kit or 'A La Carte'?). Probably go that way would be best. You could buy your own aluminum tube and make it. The expanding the tube is a little tricky without the proper tool.
 
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Heater hose is not compatible with oil. The correct hose is MIL6000 which is available from most suppliers at $5-6/ft for larger sizes. 6000 is also commonly used for vacuum pump hose (if you have a vac system).

Also, be sure you have a slit cut in the hose above the outlet. This allows the crankcase to breathe if the outlet gets iced up (easy to do in cold temps due to the moisture in the breather output). Accidents have happened due to blocked breather tubes which then lead to overpressurization of the crankcase followed by front seal failure and oil loss.
 
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