Oil from crankcase breather

Discussion in 'Oil' started by Bnugget, Sep 11, 2010.

  1. Bnugget

    Bnugget New Member

    I have a 1986 Heritage with an S & S lower end. I recently replaced my cam and after I bolted it back up and started it oil is coming out of the crankcase breather. It wasn't just a couple of ounces as in a sumping issue but half the tank was drained out. It is a continuous stream.
    The oil line routings are good. There is oil returning from the pump to the filter but no oil from the filter back to the tank. Any suggestions would be greatly appreciated.
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    Hmmm. Did you do this work yourself?

    With these symptoms, I would be worried that the timing of the breather valve in the cam chest is wrong. Do you know if the timing mark on the breather gear was lined up with the mark on the cam drive gear? If not, that is why the oil is blowing out of the breather.

    See Figure 3-55 in the attachment below:

    Gearcase Cover and timing gears

    Last edited: Sep 13, 2010

    BUBBIE Well-Known Member


    There Was a replacement of the cam oil return/breather that I put in my 97 fxds when apart along with instructions on "how to die-grind" and smooth out the area on the engine case for a Little better oil return system..

    I mention this only for those who Might be interested in this, Not suggesting it to this member..

    I don't remember if the oil return parts were metal or plastic, I think plastic and replaced with metal..?

    Last edited by a moderator: Sep 13, 2010
  4. Jack Klarich

    Jack Klarich Expert Member

    You are correct Bubbie, The MOCO went with plastic on the cheap and soon found out rhe problems along comes SS and other after markets with a steel valve with different sized windows for more scavenging:s