length of breather pipe below cowl

[n502pd]

what is the consesus on the length of the overboard tube for crankcase vent, after oil seperator. I currently have 3/4 in dia about 6--7 in outside cowling, on left side, maybe 6 in to left of lh exhaust pipe. wish to get rid of some more oil smudging on belly if possible. would the dia of the overboard pipe make a large difference? engine appears to be broken in as no decernable usage of oil over 6 or 7 hours. running great otherwise.

[Darick]

Joe, the pipe coming from my separator extends only about one inch below the cowling. It has always been dry indicating the separator is doing its job. When I empty the separator at oil changes it amounts to an ounce or so...never measured it.
I talked to Kerry about which way the tube should be cut...facing forward or aft. He said avoid positive pressure so mine is cut at a slight angle, maybe 15-25 degrees and facing aft so as to make a negative pressure so fluid would be drawn out of the separator.

[n502pd]

Thanks for the response! I have my pipe way lower that one inch, but do have the rear slice installed, but at more like 45-60 degrees. I will change the length to be 1 inch below the cooling outlet of the cowling. Is that inch measured from the fiberglass, or the seaplane lip lower edge?

[Darick]

...measured from the bottom aluminum panel, the panel where your feet would be right above. I'm not sure what is the "seaplane lip lower edge" .

[n502pd]

...measured from the bottom aluminum panel, the panel where your feet would be right above. I'm not sure what is the "seaplane lip lower edge" .

To prevent my stumbling with verbage, try going here for a good explaination of seaplane lip:

http://www.cessna170.org/forums/viewtop ... 7&start=15

And, the general idea does work well. my "lip is about 1.5 in, at roughly 45 deg aft tilt.