Flywheel Cover Oil Leak?

Steves46

Steves46

Well-known member
Good day. Now that I got my clutch installed and shifting well again on to other problems. Although my engine barely leaks when not running and parked, after taking it out for a drive and parking it, I get this rather large pool of oil that appears to be pouring from the flywheel cover plate. I looked carefully to see if it was possibly traveling down the bell housing from the oil pan, but it doesn’t appear so. Could the rear main be leaking and it’s coming out of the flywheel cover housing instead of the pinhole? My plan is to remove the flywheel cover to take a look at what’s going on inside. I’m really hoping this is coming from the oil pan gasket. Has anybody out there had a leak like this one in the photo?
 

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There is an opening on the block where the flywheel cover mounts to the block.
If my memory serves me correctly, it is at the back of the cam shaft. There should be a gasket between the block and flywheel cover. The gasket seals the hole when properly installed.
This could be your problem.
 
Generally, when the gasket that Dick M. cited is missing, you can see oil dripping from the flywheel inspection plate and through the hole in the bottom of the flywheel housing as the engine is running. You say the oil doesn't leak when the engine is running, but does leak when the engine is shut off and a puddle forms beneath the engine. This is the classic loose rear main bearing leak syndrome. There is either too much clearance between the crankshaft journal and the Babbit bearing material, and/or the Babbitt material is broken. If the bearing thrust is shot, the crankshaft will move fore and aft as the engine is running. This causes oil to pump past the rear main bearing "seal" (It isn't a seal). Since you write that the oil doesn't leak when the engine is running, the thrust is probably o.k. But observe the crankshaft pulley anyway as the engine is running. Back and forth = worn thrust.
My bet is that at the least, the rear main bearing cap needs to be adjusted. If you don't also adjust the center main bearing, you are wasting your time with the rear bearing. The crankshaft "whips" as it spins, causing a flexing inside the center main bearing. When the bearing clearance becomes too great due to this whipping action, the rear main bearing will begin to leak.
Plan on spending a day or two adjusting all the main bearings, although the front main bearing rarely needs more than one thin shim removed, if even that. It is critical for oil leakage control that both the center and rear main bearings be adjusted in tandem. A pain in the you-know-what, but if you want to eliminate (for a while) those embarrassing puddles of oil beneath your car, you gotta' attack the main cause of oil leakage in the areas you mentioned. 'Might as well adjust the rod bearings while the pan is down. No better time than then to eliminate that annoying rod rattle. Take heart: Adjusting the rod bearings is a piece of cake compared to adjusting the main bearings.
Marshall
 
I had the same oil leak and it turned out to be from the cam bearing. As Dick said there is an open hole at the back of the engine were the cam is. My solution was to use a different flywheel housing that was flat and a new gasket with plenty of gasket cement. And the two spacer washers at the top. My old flywheel housing was not flat.
 
Thank you very much. I will certainly take a look. Like I mentioned below, I certainly have some work to do.
 
In retrospect and with 100 years' worth of engineering progress behind us since the Model A was manufactured, I wonder why Ford engineers decided to leave such a large hole in the engine block at the back of the camshaft? To what end? Why was this not simply closed off in the engine block casting, thereby preventing yet another potential source of oil leakage? If the engineers were concerned about the damage caused by a constantly-turning camshaft, why not install a Welch plug or something removable that could be replaced as an in-service procedure? I have replaced the missing flywheel housing gasket several times in "restored" Model A's, whose owner/mechanic should have asked himself where that left-over half-moon gasket that ought to go. I could actually see the oil dripping around the camshaft area when the engine was running and instantly knew that the special gasket had been left out. And previous owners never questioned why this was so??? Jeez....
Marshall
 
Marshall V. Daut said:
In retrospect and with 100 years' worth of engineering progress behind us since the Model A was manufactured, I wonder why Ford engineers decided to leave such a large hole in the engine block at the back of the camshaft? To what end? Why was this not simply closed off in the engine block casting, thereby preventing yet another potential source of oil leakage? If the engineers were concerned about the damage caused by a constantly-turning camshaft, why not install a Welch plug or something removable that could be replaced as an in-service procedure?.
Marshall
Click to expand...

i suspect that cam journal is open only for the ease of line boring the cam journals during manufacturing. money savings.


if the gasket is in there and sealing it should not leak.
ou
 
If the rear camshaft bearing (journal) had been 1/8" narrower, a Welch plug or some kind of sealing end plug could have been pressed into the back of the engine block after the hole had been bored, effectively sealing off the back of the engine. That bearing (journal) on the camshaft is wide enough that a measly 1/8" shaved off wouldn't have affected anything adversely. Expecting a paper-thin gasket to seal off this fairly high pressure oil area to stop leakage was highly optimistic. See how many postings on this website discussing problems with oil leakage in the back of the camshaft have been posted over the years. All these issues could have been avoided had this hole been sealed with a plug. But of course, the list of "should have done's" in the Model A is almost without end! Too bad we weren't around in late 1927 to advise Ford engineers on how the Model A SHOULD have been designed in a few months' time!!! :)
Marshall
 
The Burtz flywheel housing has an O ring there. Problem solved.

Marshall has a good idea. My friend Ted did exactly that. Shaved a little off the end of the cam and put a Welch plug in.
 
There is another possibility. I could be transmission oil. Check the leakage oil with the color & viscosity of the transmission oil and your motor oil.
 
Update. Hopefully the photographs uploaded. I removed the oil pan and although everything looks really nice, it looks like I have a rear main that went out based on the fragments that I found. I guess the question of the day is is this a repair that can be made with the engine in the car or does the engine need to be removed? I am going to assume this was the cause of my major oil leak? I was pleased, however, to find no sludge in my oil pan and the oil pump filter was nice and clean. The engine was overhauled in 1978. Has always appreciate any guidance as to how I should go about this repair.
 

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It may seem like more work but it is always easier in the long run to pull the engine and put it on a stand. After you pull and re install the engine a few times you can do it in your sleep.
 
I had a feeling this would be the case. On the bright side, however I am hoping this was the root cause of the massive oil leak was experiencing.
 
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