Morris Minor Owners Club

I've got the engine and box separated to investigate an oil leak from the rear of the engine. being a 1275 I suspected the scroll seal. However on inspection I can see there is a thin layer of oil around the whole area inside the bellhousing, none on the clutch/flywheel and none on the back plate or visible area of the seal. However I can only see the top half of the seal.
There is a leak from the rear of the head; either the gasket I suspect or maybe there is a oil plug around there somewhere? the leak is related to the engine running and not a static drip.
Ideas please.

Not from the front seal of the gearbox? Surely the oil must have got onto the rotating bits to get all over the inside of the bellhousing, perhaps it's on the (hidden) front face of the flywheel. Scroll 'seal' sounds most likely as they have a certain reputation.

The 'head' leak seems unlikely since the oil feed is at the front - maybe from the rocker cover. The second leak - inside the bellhousing - does seem like it must have come from the gearbox if there really is none on the flywheel. Usual reason for scroll leak is pressure inside the engine crankcase - from piston blow-by. Make sure the breathers are all really clear and connect one of them to the carb to ensure there is some suction on the crankcase.

Ah, now this may explain my problem as well..!
I have a 'drip' from the 'clip' on my bellhousing, and the oil is coming from the engine as the level is dropping. The original 1098 engine was rebuilt 1000 miles ago. It has been gradually getting worse as I have been raising the 'revs' after running in...According to my Leyland 1970 manual there should be a crankcase breather valve fitted I guess to put the crankcase under vacuum, and draw air from the air filter housing via a short hose. (When the unvented filler cap is removed the revs should rise 200 rpm). The valve has been completely removed at some stage in the past, the carb capped with a bit of tube and a bolt (nice) and the oil condenser just breathes to atmosphere....
Also I was told to use 10W/40 oil, could this have an effect too?
Anyone got a spare 2nd hand valve I could buy?
Cheers
Dave

I believe the oil in the bellhousing is from the gearbox. The engine crankcase breather is clear - I ran some gunk into it and heard it dripping into the sump.

Dave C - don't worry about the 'valve' - just join the breather directly to the connection on the side of the carb. It will be fine. Better to use 20W50 oil in these engines, certainly in summer, although the 10W40 may be fine in winter.

Tubing and clips are on my shopping list for lunchbreak, and I'll switch the oil grade at the next change, thanks for the advice!

Piped up as you said BMC, and all 'scroll' oil leaks have now stopped. Magic! I seem to have a very small drip from the bottom of the timing chain cover gasket. I'll degrease and find out where it's coming from.
Dave