Morris Minor Owners Club

The 1275 needs negative crankcase pressure otherwise it will blow oil past the rear scroll (not really a seal). Ideally the rocker cover breather should go back into the combustion process but there should be a vent from the crankcase also. Not sure what you mean by an oil filler cap seal as there isn't one?

Make sure the breather pipe is not kinked or blocked.

I'll check the pipe tomorrow for blockages.
There was no rubber on the underside of the oil cap. I've got this one on now: http://morrisminorspares.co.uk/shop/pop ... php?pID=19

I always use vented caps.....

When you pour oil into the rocker cover on a 1275 engine it takes a long time to dribble past the push rods in to the sump, unlike the smaller engines. For crankcase ventilation the same thing applies in reverse, the crankcase pressure will not escape past the pushrods in to the rocker cover quickly enough to relieve the pressure.
Since there are no tappet chest covers with breather pipes as there are on the 1098 then the 1275 needs a breather pipe on the timing chain cover. The rocker cover ventilation is not sufficient.
Now refer back to my earlier statement. Still not managed to download the diagram.

Paste it into a Word document -and then attach that ? I agree - if the fumes are considerable it is indeed possible that the push rod route may not be sufficient. Timing case breather is a nuisance - but it is essential with a 1275.

I scanned it into the computer, clicked on browse, opened the document then clicked on submit and it kept deleting the reply.
It has always worked in the past.

I've just checked and there are no blockages or kinks in the pipe.
I've just acquired a tappet chest cover which I was told would be ok for the 1275. Do you think this would work? photo here:http://www.23hq.com/lordanthony/photo/4 ... id=4299977

Mike - is the attachment too large? Sometimes there's a restriction on how big a file will be accepted.

If your scanner gives you any options then you should be able to reduce the quality or size of the image. Sometimes it states the size in dpi and sometimes in pixels. If you choose a lower dpi say 100 or 150 or about 1024 pixels wide then that should make it small enough.

Everyone's help and suggestions are really appreciated. What a nice bunch of people.

You don't have removeable tappet chest covers on a 1275 so you could not fit it as is. You could cut off the breather and weld it into the front cover.

There is nowhere to fit that thing! Only 1275 to have cam follower covers - was the Mini Cooper S block!