how does this happen?

Discussion in 'Mechanic and Repair' started by rbig, Jun 4, 2005.

  1. rbig

    rbig LawnSite Member
    Posts: 112

    I have a John Deere 400 with 60" deck. I had to take it to a temporary job at our church 3 acre site while the church mower is being fixed in a shop. There are lots of ditches, ruts, culverts, etc that I mow through. When my tractor tilts going up or down a ditch, or is sideways on a slope during a turnout, I get oil smoking until the quantity that got in the cylinders on the slope burns out, especially if the oil level is full or slightly over.

    The question I have is how the oil is getting from the crankcase/pan area into the combustion chamber? What is the path being followed when I'm on a slope surface?
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022


    You asked a engine related question and didn't say what engine is on your unit ? post model and spec. numbers that would be helpful !!!
     
  3. rbig

    rbig LawnSite Member
    Posts: 112

    Well, I was thinking in general. But specifically, it's a Kohler K-532
     
  4. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    I don't know your engine in question, or work that many small engines period, but my first thought was a failed PCV system.

    An Engines PCV system allows crankcase pressure to vent out back into the intake tract and be burned up again, if your on a slope, I'd imagine oil is getting past the PCV valve and being fed back through the carb.

    Of course, This is from a guy who worked on car engines.

    EDIT: Are you sure its oil being burned and not excessive fuel? (Oil will be blue, fuel will be black).

    When you turn a carb on its side, its going to dump tons of fuel into the cylinder.
     
  5. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022


    I studied the break-down of your engine and the only thing I can come up with is possibly when the engine is sitting sideways the oil is running into the cylinder and when the piston comes down its acting as a plunger and forcing the oil past the rings possibly through the ring end gaps. OR the oil in the valve spring ports is not draining because the return port is higher than the valve stem and being sucked through worn valve guides.

    This is in deed a good one !
     
  6. rbig

    rbig LawnSite Member
    Posts: 112

    I'll check the pcv valve. Thanks.

    Wow! Here I am assuming my engine has a pcv valve. Think it does, but not sure. Anyway, I'll find out.
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022


    This engine doesn't have a pcv valve !
    But even if it did it would smoke all the time !
    I was a Automotive Service Technican for 12yrs. before changing professions.
     
  8. Smalltimer1

    Smalltimer1 LawnSite Bronze Member
    Posts: 1,223

    It does sound like a ring issue.
     
  9. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    I was just throwing out suggestions :)

    Your worn valve guides suggestion intrigues me, but I think if they were that worn, it would smoke all the time.

    Probably is a ring issue. Whats the hours on the engine?
     
  10. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022


    Well the worn guide suggestion is only when he's on a slope like he said,The hot thin oil could be sucked through the intake guide when it puddles around the valve stem,See no stem seals on this one.
    Kohler hasn't made this engine for many years,Thus assuming this is probably a high hour unit.
    This is how I based my (suggestions) only.
     

Share This Page