Thanks Dennis that's exactly the problem I will do what you have mentioned. As for the crankcase pressure should I be worried,the engine has good compression on all cylinders still. Thanks 

Thanks for the advice h_lankford the under part of the distributor has a small hole which the oil seeps out it doesn't collect in the cap. The mini does seem to chug a little at speed though no oily plugs if anything I would say its running a little hot as the plugs are light brown color.

I've had this problem with a new distributor for a A+.  If you pull the distributor there is a small hole in the lower part of the body to allow oil in to lube the shaft.  Just clean the area and seal this with a little dab of silicone and you should be good.  Crank case pressure is forcing too much oil up through the hole and oil is being forced ou the bushing .  With the hole sealed there is still enough oil that will get in through the base of the shaft.

Cheers

Dennis

I have a 1275 A+ with 65DM4 that does not leak

some thoughts:

what do you mean from the upper part of the distributor? did you find it accidentally when taking the distributor cap off or was it oozing out all over the place?

Does the car run well ignition-wise?

Does the car run well otherwise- specifically do you have good compression, non-oily plugs, etc?

Does the car vent oily fumes through the opened valve cover hole? Rev it up when you do that. If you have a bunch of blowby, then yes you have a problem.

This is FYI and may have nothing to do with minis, but I do see that you have replaced your distributor:  I once had a Ford product whose electronic distributor that pumped oil up its shaft (with spiral grooves I think)  into the base of the distributor. The malfunctioning electronics led me to look in there. With the cap off and under the guts, there was a 1/4 cup or so of oil sloshing around, not just oil fumes in other words. There was a recall or technical bulletin on this for Fords, they redesigned the bottom of the distributor shaft to have a collar to block some of the oil splash reaching the end of the shaft so that it could not pump as much up. To get that, I had to buy the whole assembly.

Since your replacement did not help, I wonder if you could just drill a 1/8 inch or so hole in the bottom of the distributor base and let the collected oil run out?

Harvey

PS one other thought - Did you replace the vacuum advance when you replaced the distributor? If still using the original vacuum device, isn't it bolted right onto the side, sort of intergral rather than external?  if so, could a leak in the device diaphragm 'transmit" vacuum to the inside of the distributor, thereby sucking up normal oil up the shaft at a faster rate? I don't know if it is airtight enough to do that. Just a wild thought.

Hey guys I have just joined the mini scene and am looking for some helpful advice. Basically I have a 1275 A+ engine & electronic ignition 64dm4 distributor,now for the question the distributor is leaking oil not where it meets the engine block but from the upper part of the distributor. I have checked all breathers,changed the oil ring at the base of the distributor shaft,even replaced the distributor this hasn't worked as it is still leaking. I was informed this could be a crankcase pressure build up but oil isn't leaking anywhere else I.e dipstick etc.

Any ideas guys ???  Thanks