While doing some work on 1937-60 I notice that there was a coating of oil in the air filter,carb top and other areas around the air cleaner. I know this system is supposed to draw crankcase fumes [ but not oil] into the engine at the back of the filter can. My understanding this was a 1 year design. I am thinking about teeing the two engine pipes together and making a old style road draft system. Any other thoughts or ideas. Steve
Joe,
It was used in 1937 and 1938 as was the electric choke.
The Johnny
If the breather is pulling oily fumes through this system it usually means a tired engine. Too much back pressure from worn rings or bore will cause this. The later system just dumped this stuff on the road. It may be possible to use one of these after-market valves in the pipe that filters the oil particles out.
Thanks
For what it's worth, the "37 is kind of an oddball in that it has no rear main oil seal; possibly no front seal either. Some have adapted PCV valves to later flatheads, but I'm not sure how this would work on a non-sealed motor as far as being effective, vacuum leaks, etc. Would converting to a road draft tube cause more rear main bearing oil leakage on a '37? could that goofy but messy vacuum tube be the best choice for a '37??
Joe Gibeault 12138