Like many Minis, mine always leaked oil. When I did the restoration and transmission rebuild, I replaced all the seals and gaskets, used a gasket dressing and was hoping for an oil-leak-free Mini.
Unfortunately, no. It started off as a drip, but turned into any oil added above the "min" line on the dipstick will leak out overnight.
It seemed to be leaking from the speedo drive housing, but I bought some dye, added oil, waited for it to leak out and pulled the engine/transmission.
The dye showed oil on the bottom of the drive motor mount and the nuts on one of the studs.
I took the speedo drive off and found this:
Not sure why I didn't notice those cracks when I had everything apart before. Maybe they've gotten worse, the leak had.
I cleaned it up best as I could with heat and solvent, tapped the metal back together to close the cracks and used the die grinder to carve some metal out. I did some fooling around with aluminum brazing/soldering rod, which managed to work with one of the cracks, but it was not easy to get the aluminum hot enough for long enough, even with the oxy-acetylene torch.
So, I slathered it with JB Weld, put it together with new gaskets and copious gasket dressing. Seems to be holding up so far. I'm planning to drive it to a show 150 miles away on Sunday. Hopefully don't have to add any oil.
That's a pain but hopefully solves it. I have a leak from the same area that I need to investigate whenever I pull the motor next time.
Of course any time something like that happens its to the part that's not easily replaced. If you ever need a transmission case I have several different varieties of them.
I can likely find a used case up here too; they sold a lot of Minis in Canada in the 70's.
If your engine has the metal breather can on the timing chain cover, check the bottom of it for pin holes, I've seen several like that. Since they're NLA I use JB to cover the bottom of the can, it seems to work if you get it clean enough before you lay it on.
Hope your repairs cure it, oil leaks can be pretty frustrating!
No more drips!
This engine doesn't have the breather can on the timing chain cover, but does have the breather on the tappet chest cover. Originally, in addition to the air pump, this Mini had an evap system with charcoal canister, etc. I'm going to be recreating it using a new GM charcoal canister to try to minimize the gas smells in the garage. Once I get it together, I'll describe it in a new thread.
I hope it works, cause mine stinks of gasoline fumes when it's parked in the garage!