Strange Leak From Clutch Housing

M

Marcus J

Junior Member
The engine is rebuilt, but before I have it torn down again, I wonder if anyone recognizes this leak?

When the engine was warmed up oil began to run down the from of the clutch housing, down the flat side facing the oil pan, from the joint between the engine and the clutch housing. The bolts for the seal plates were tight. I applied silicone on the outside (as a temporary solution) and that worked. But then (and maybe it had all the time) oil started to drip from the hole in the bottom of the clutch housing. Funny thing is, as soon as I revved the engine, the drip stopped, and then on idle, it started again. Perhaps one drop every second second.

Any theories?
 
Did you put in that half-moon paper gasket between the engine block and flywheel housing during assembly? If not, that will for sure cause the leak you describe.
Trimmed rear main bearing shims tangs will also create such a leak, as I discovered two months ago. Also, too much clearance in the center and rear main bearings will cause a leak. These are the obvious sources on newly-rebuilt engines, especially tht missing paper gasket.
Marshali
 
Thank you Marshall!

But would/could a missing, or ill fitting, paper gasket also lead to a leak via the clutch housing?
 
Marcus J said:
Thank you Marshall!

But would/could a missing, or ill fitting, paper gasket also lead to a leak via the clutch housing?
Click to expand...

Certainly. But understand the leak path is from the rearmost journal of the camshaft, out the hole on the rear of the block, and down the interface between engine and flywheel housing.

Not to say that there might be other rear main seal leaks - like Marshall's rear main shim tab (usually where it meets the slinger ring brass insert) or even at the square cork/oil pan gasket/rear main cap interface. (Like land battles fought at the juncture of two maps, this seal tight battle is fought on THREE.)

The oil pan/rear main is probably the easiest to check into. Clean everything and use LOTS of Permatex No. 2 in this area when you put it back together again.

Joe K
 
Wouldn't be the first one I ever saw that leaked almost immediately from a bad rear main or a bad babbitt job that was cut too much or the thrust cracked right off.
 
Thank you. I will check the paper gasket tonight. The engine has new modern style insert bearings and modern type seal at the rear - it is completely restored (new cam etc), I´m hoping for something forgotten or not aligned.
 
Marcus this sounds like a rear main leak
they normally drip straight on the inside of the flywheel before running off to the flywheel housing
when you increase the revs the extra centrifugal force lets the flywheel hold much more oil
 
Hi!

Here is what I see when I
take off the flywheel. There is oil on the bolt to the right, not on the left bolt. There are oildrops to the right on the black plate, under the bolt. No oil drops to the left. There is oil in the recess/gap between black plate and red cap - but NO oil under the red cap beneath the flange that hold the flywheel.

Any clues?

 
The two main bearing bolts should have sealer around them.

Hold a mirror on the front side of the flywheel flange to see if oil is on it.
 
There is a thin oil film on the flywheel. If oil comes via the bolt to the right, which it obviously does, could the bolt be the same source for the oil that ran down the front outside of the flywheel housing, before I sealed that leak with silicone on the outside - in the area between the fly wheel housing and the oil pan, or maybe they are two different leaks?
 
I think you have one leakpath, and the fact that a drip hangs on the passenger side bolt indicates that it is associated with the rear main: possibly a shim that has been cut or modified, possibly oil backing up from an improperly installed drain tube (sometimes they can be installed to actually block the drain gallery), possibly an absent drain tube (windage from the engine will drive oil back up the drain gallery and motion of the engine clockwise looking front will cause it to overflow on the right side)

I think you're at the point where you should pull the engine. And check it out further. To have these sort of problems so soon after a rebuild tells me that something is not right in the fundamentals and you should check the fundamentals.

Edit: It could well be that the bearing shim on the passenger side is "misplaced" and is touching the shaft. Acting like a scraper, this would yield a leak at the bolt such as you see. Better to check the setup.

Joe K
 
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Marcus J said:
Hi!

Here is what I see when I
take off the flywheel. There is oil on the bolt to the right, not on the left bolt. There are oildrops to the right on the black plate, under the bolt. No oil drops to the left. There is oil in the recess/gap between black plate and red cap - but NO oil under the red cap beneath the flange that hold the flywheel.

Any clues?

Click to expand...

Hand crank too fire the engine, then with the engine running, view the
oil leak..
 
Thank you all for your knowledge! I was considering if this was something I could deal with myself, or if it should go back to the guys that restored it, and it has to go back - and they have agreed to fix it.
 
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