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Hot Rods Misting oil problems flathead ford

Discussion in 'The Hokey Ass Message Board' started by Flatheadjohn47, Oct 20, 2015.

  1. I have built many flatmotors over a 55 year period.This particular block is 39 truck(3 3/16 bore with .090 overbore.) This block puts out so much oil misting that the vent tube in the pan(front passenger side) blows oil constantly and I don't know why.The end gap on the rings was checked,new bearings(good oil pressure 40-50 hot at 2500 rpm.) the crankshaft slinger is in place and run a standard fuel pump with umbrella on push rod.Run big intake valves with MCF camshaft.370 lift,Weiand cheater heads,Edelbrock slingshot perf stainless mufflers(glass packs)All mounted in a 32 cabriolet Henry highboy roadster.Compression gauge reads about 140 all cylinders.Engine does not smoke nor foul plugs(have 43 main jets in 97carbs-runs good just "blows oil constantly out the vent tube" and not much fun to drive. Any suggestions are appreciated;don't know what else to check or modify. Breather on top of fuel pump has no limitingobstructions and vents well to atmosphere. Thanks flatheadjohn47 Texas 979-595-7324 cell.
  2. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,683

    Bruce Lancaster
    Member Emeritus

    One common problem is missing tin in the gotta have the tube above the vent that sticks up in the front of valley, the tin pieces that cover drain holes in center, and tube under fuel pump stand. That front tube would allow oil from upstairs to drain right down to the exit.
  3. Jimmy2car
    Joined: Nov 26, 2003
    Posts: 1,707

    from No. Cal

  4. I agree with Bruce - you're probably missing the front vent-tube that directs the gasses down to the front of the block and out the pan. Pull the intake and see what you find.
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  5. alchemy
    Joined: Sep 27, 2002
    Posts: 14,580


    If none of the parts are missing, what's the cure? Is this an engine you could install a PCV into? Plug the bottom vent and use the PCV in its place.
  6. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,683

    Bruce Lancaster
    Member Emeritus

    The engine seems healthy from info given, but of course it's new and might well have an unsuspected problem with the build.
    That front pipe is a direct route straight down to the outlet vent, and if missing any oil in the valley can just roll on down. If loss out the vent is enough to be a major problem, a PCV might turn the thing into a diesel chugging along in a cloud of stinking smoke...I'm hoping this is just a lost pipe and gravity coming together.
  7. lowsquire
    Joined: Feb 21, 2002
    Posts: 2,564

    from Austin, TX

    Are you running the oil to the FULL mark or higher? those year engines have no oil control in the sump, and if its a quiet runner you can often hear the crank slapping the oil at idle if its too high! Surely that would add to the issue. try dropping the oil level a little. i built a sump baffle in the last '39 I did to combat that issue. Id also add a PCV valve.

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