Ok today I drove my 1100 and oil went everywhere. It appears to be coming out of the side cover breather and spraying in a big way. Plenty of air coming out of the oil cap breather and when I remove the oilstick the oil is splahing up and out of the hole. Looks like I have positive sump pressure.
Any ideas?

The crankcase will always be pressurised. Do your breathers go to the carb or vent to atmosphere? The routing it to the carb/manifold will help, they will pull a vacuum.

Otherwise is it over filled with oil? Is it an older engine, could be worn out bores.

Just checked the compression. 140-150 on each or there-abouts. This just started today, I thought maybe a broken ring, because when I say oiled up, oil is dripping from everywhere, running down the inside of the bonnet when it's up. The side cover breather is one of the crimped ones, with a tiny gap in the crease and not meant to go to the carb. The rocker cover vent is in the cap and it is a pin hole venting up.
It's like oil is collecting at the breather point and being sprayed under pressure. Oil on the dipstick was normal, but will probably be low as I reckon 200ml min has collected on the ground after parking it.
Like I said, it want doing it yesterday. Could it be a blockage in the oil filter causing pressure to be released elsewhere?

From memory there's an oil pressure relief valve next to the distributor.

Doesn't sound good at all. You say it is literally being blown out the cap and covers?

Oil relieves back into the sump all the time in regulating oil pressure, it won't have an effect at the breathers.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Yes Mick, you can see oil bubbling on the side cover breather at idle. If I remove the dipstick at idle oil droplets are being ejected out the dipstick hole. When I rev it it doesn't appear to immediately spray oil, but there is a wet smoke stream shooting out and the oil cap hole looks like a steam train stack blasting out a smokey stream.
When I drove it for about 5 mins, the underside of the bonnet is completely covered in oil running down and dripping into pools under the bonnet corners and the radiator fan cowl is filled at the bottom. Smoke is visible in the rear view mirror from oil getting on the exhaust.
I've never seen anything like it. I can only think that there is a heap of blow past the rings intermittently and it is pressurizing the crankcase, entraining oil and ejecting it with the gases.
I would have thought excess oil pressure from a faulty oil pressure relief would not cause a gaseous pressure increase like this. Is it possible to have the exhaust venting into the crankcase somehow?

I don't think that sounds very positive at all from the description. I would have thought the compression check would have given it away however without oil being put in the bores, but unfortunately there's no normal reason for this oil spray to happen.

Might be time to lift the engine, or at least lift the head.

_________________
SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Do a leak down test first. It will tell you if you have excess blow by even if the compression looks good. If the rings (or a broken one) are leaking into the crankcase, you will be able to hear the air (or see the oil bubble sin your case) coming out of the breathers.

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the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

Chubby.

Are you running a mechanical fuel pump?
If the diaphram goes, it will fill the engine with petrol and leak everywhere.

Also check the oil guage line (if you have one.) Mine went and sprayed oil around.


Cheers
Alex.