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Marmon 1932 125 hp front crankshaft pulley oil leaking


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I am not at all familiar with your marmon engine.  I do think it would help if you posted more pictures.  Such as an inside view of the timing cover and whatever part threads into the front of the timing case cover.  Your picture shows what I believe is a simple oil slinger in front of the crankshaft sprocket.  I believe the your timing cover could be modified to accept a modern neoprene seal if there is sufficient room.

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42 minutes ago, PartsAncient said:

whatever part threads into the front of the timing case cover.

There is nothing that threads in there.  He said 0.3mm gap, which is the same close fitting on some transmission input shafts that also have those 'threads".   The spiral threads pull the oil back into the trans or in this case pulls the oil droplets back into the cover when the shaft is spinning.

 

If the engine has too much compression blow-by past the rings, or if the engine breathers are plugged (or wrong unvented oil cap) then oil would blow out past the spirals.

 

I agree  that there might be a way to rework the cover to take a seal.  You'd make a new larger I.D. steel ring to weld in place of what's there.  

 

and maybe a thick felt seal like mentioned? ...placed/compressed between the cover and slinger, but then a lot of work to take back apart if it did not work. Might be worth the gamble IMO

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5 hours ago, PartsAncient said:

Isn't that where the crank hole cover should thread into?

No, because this is completely hidden by the crank pulley assembly when it is installed.   The pulley/hub "nose" fits through that hole.  He said the clearance between the hole and the pulley nose is only 0.3mm. ( .012" ).  

 

To me, I doubt there ever was a extremely super thin felt liner in there.  The threads would not be a great way to hold paper thin felt.  A felt or leather front cover seal normally sits into a deep groove, and the felt is substantial, not something thin.

 

The more I think about it, I like the post that said a felt disc.  I'd try to calculate what thickness it needs to be so that it would be permanently compressed by being between the slinger and cover.  Then soak the felt in oil first so it won't wear a bit on first starting.   Why would that felt seal not work?   I don't think it could harm anything?  

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I'd be a bit suspicious of the breather business. If there is pressure in the crankcase it will push oil out this type of "seal". If there is any "stuffing" in the breather it may be plugged up. 

Are those thread spirals metal?  I have a Volvo tractor with a similar setup and it will leak like a savage when the breather cap gets plugged. 

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It’s an 8-80? I see the sealer on that cover and I immediately think someone rebuilt it that doesn’t know what they are doing. Does the car have a oil filter set up on it? If so, is it stock, modified, or aftermarket? Excess oil pressure is very often “dumped” out the end of the camshaft forward most bearing, to lubricate  the chain and gears………..so modified/changed cam bearings could cause too much oil to the cover. The oil pressure relief valve could be internal or external, or both. We modify all our covers to take a modern seal. Like others said, make up a steel sleeve, bore the cover, and weld it in place. For an oil leak there large enough to cause problems, it’s more than likely something in the system has been modified. Also, many timing chains have an external oil dump pipe for them……and the can be installed at a bad angle and also cause problems. 

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I had the same issue in my  1929 Marmon model 78 engine, and the solution was adapt a modern seal on it, when the engine was rebuilt. It works well.409135B1-F09F-40F9-8B05-B212FDB9234C.jpeg.1fcf88162e4ce7cc84b4873127680918.jpeg

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