Hercules IXA Rear Crankshaft Seal Leak

oxtioneer3399 · Jul 23, 2015

I recently rebuilt a Hercules IXA engine in a 1934 Plymouth tractor.It runs great but it leaks oil badly out of the rear of the crankshaft.It does not appear to have a seal,just a slinger on the crankshaft.Is there a cure for the oil leak?What did I do wrong?

Steve@Advance · Jul 23, 2015

If there is no seal, four things come to mind that can cause it to leak:

It's simply overfull. Any idea how much it should hold? Dip stick could easily be wrong, typically the oil should not touch the bottom of the crank unless it has dipper rods, then there would be a tray that needs to be in the oil.

The crankcase is pressurizing, as in the vent tube is clogged, or excess blowby (not likely with new overhaul). Try removing the oil cap, see if the leak stops, hold your hand over the oil fill, see if it builds pressure. Is the cap vented? Should it be?

The rear main has too much clearance, allowing excess oil to flood the slinger. That should also show as low oil pressure, knocking.

The engine has been tilted up in front, That will cause it to leak, but should stop as soon as the position is corrected, but it will still be draining down from the clutch (yuck!) and out of the bell housing.

oxtioneer3399 · Jul 23, 2015

There is no blowby and it runs good oil pressure.It does have a homemade dipstick,done quite nicely from copper and brass,it was not marked for a level.I put in four quarts and it came about 1/2 inch up onto stick,so I thought that was good,usually the minimum for any four cylinder engine.I do not have a manul that tells me the capacity for the Plymouth,maybe someone knows or could give me the dimensions of an original dipstick and where the mark is,thanks for the reply.

Steve@Advance · Jul 23, 2015

Other thoughts...

There has to be drain holes in the bottom of the slinger cavity that direct the oil back into the pan. If they are possibly blocked, gasket sealer? Long shot, the thrust bearing isn't right and the slinger is too far forward or back blocking the drain?

Is the slinger part of the rear main cap? Is there pressurized oil passing through the cap? Would a very minimal amount of sealer stop oil from coming to the outside from under the cap? Any packing type seals running vertical on the sides of the main cap or slinger housing?

Any possibility the oil is not coming from the rear main? Cam plug, oil galley plug, from up above?

Hercules IXA Rear Crankshaft Seal Leak

oxtioneer3399

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Steve@Advance

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oxtioneer3399

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Steve@Advance

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