Oil Leak Fixed!

C

CatMan1

Senior Member
I think we fixed the rear main leak. It took us awhile and a lot of research, fretting over it. Having the engine apart we noticed that the engine re-builder had put two 'paths' in the bottom bearing cap like you would for a Model B engine. Also he drilled a hole in the 'X' of that so oil would drain into the little valley below. So we plugged that hole. The drain tube is the correct length and we noticed some crud in there so we cleaned it out. Checked the bearing clearance via aluminum foil and it was right on. Of course put on new oil pan gaskets. Filled it up to 'F' (not counting for what is in the dipper tray now) and drove it. No leaks! Dry. I checked this morning and the cotter key seems to have a drip on it and the tray underneath the car has a drip the size of a Silver Dollar in it. I think this is a success? Yes?
 
Yes ! Certainly ! A’s shouldn’t leak while running, only when you stop the engine. A dollar size is the right size !
Of course there shouldn’t be an X carved into the lower bearing shell at all !
 
Good for you and for your sake I hope you have the problem solved.

All the work I have done with my leak has not yet stopped the leak!
The search goes on for trying to figure out why! :(
 
Good job or running down the problem. A properly restored rear main will not leak more than you have.Agree cap should not have an X and good move plugging the hole to the drain. Some bit of oil has to drain to the rear to oil the thrust surface.
 
Curious about the situation of the hole drilled into the drain channel at the bottom of the rear cap. Some guys claim this helps reduce leaks but I've yet to see anything definitive about this practice. Especially curious because the guy that pored and bored my mains suggested it and I haven't assembled the engine yet.
 
ursus said:
Curious about the situation of the hole drilled into the drain channel at the bottom of the rear cap. Some guys claim this helps reduce leaks but I've yet to see anything definitive about this practice. Especially curious because the guy that pored and bored my mains suggested it and I haven't assembled the engine yet.
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I wouldn't have one added. I was told it was wrong. Somewhere I read that the best thing you can do is just put your Model A back to specs and you'll be fine. Maybe? I'm trying to. Did that hole cause more issues than it solved? Who knows. Maybe it was flooding the channel too fast?
 
Ford specs on the application of oil grooves have proven to be false ! Engineers of that era did not understand hydrodynamics. You want a solid oil film to carry the crankshaft. So, never put any grooves into the lower crank caps, just leave it alone after line boring. You may do whatever you want to the upper half of the bearings, but it won’t be necessary. Oil grooves, either spiral or X, are killing your lubrication !
 
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