Oil Breather Tube

[N3322G]

I read somewhere that the length of the oil breather tube on a Twin can create oil drips if it is too long. Does anyone know the correct length and how to measure it?

[Bruce Thumann]

Hi Pat, don't know about overall length, but I once read an article on breather tube placement which stated that the more it protrudes through the bottom of the cowl, the more oil loss you will see due to slipstream vacum. The author advocated bare minimum protrusion into the slipstream. Also, the article stated the importance of having the vapor path at the top of the engine arranged so that the vapor traveled above the vapor outlet port on the engine. I believe this was to allow much of the oil vapor to condense on the sides of the rubber connector hose and flow back into the outlet port. Maybe someone else will remember this article and where to find it.

Bruce

[N3322G]