Maybe high crank case pressure?

_________________
Respect mine and I'll respect yours.

front cam bearing put in upside down

_________________
did I tell you that I won a trophy?

Nope, it's back to front.
This causes a full time flow of oil up to the rockers, instead of a short pulse every camshaft rotation.
Sorry to say, motor has to come out to fix this on an 1100S etc block with no side covers.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Can I put a small restricter (orifice) in the rocker post ?
If the top of the engine is receiving "full flow" is there a danger that the rest of the engine is being starved

_________________
Find a job you love and you will never have to go to work !

Some race guys tap the oilway and put a restrictor (grubscrew with a small hole) in the top of the block. Usually when running needle bearing rockers.

If it pumps a litre of oil up there, that's 1 litre less in the sump. Probable oil starvation on RH bends unless you have a centre oil pickup fitted.

Personally, I'd pull the motor and fix it properly.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

on the topic of restricting oil up top. a minispares exploded diagram shows a cam oil restrictor plug 1a1964 as NLA . any info about the use /timing/ age of this part..... it was at the bottom of the oilway from crank cap up to cam?

I am having trouble at the moment imagining this has been happening for a long time. So what is the history of the engine? Was it just rebuilt? It can't have spent its entire life filling the rocker cover up?

Is there anything else going on up top which might block oilways? Is there evidence of the use of a lot of silicone around the rocker gasket?

_________________
SooperDooperMiniCooperExpertEngineering

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

There is a restrictor in there usually, between the main bearing and cam, but it's a pretty big hole in it. Its purpose is more to keep main bearing oil pressure up if the cam bush is worn.

[edit] This problem usually happens after new cam bearings are fitted. That's why I always get GR to fit mine, so I don't F them up.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I bought the car on eBay (unregistered) about 10 months ago and have been fixing lots of little issues over that time.
This is the first time I have actually driven it anywhere. Hence it is a NEW problem to me.
I don't know what happened in the past. Perhaps the previous owner found out about all the issues and decided to move it on. It has a great body and all of the other little issues have been fixed.
Just one to go

_________________
Find a job you love and you will never have to go to work !

close enough....

_________________
did I tell you that I won a trophy?

I think Simon stands his block on its end while fitting the front cam bearing so he's right, it is in upside down.

_________________
ex-NSW Police 1970 MK II Cooper S
VMCI #43

If you fit a new cam bearing do you need to line ream them as per the manual that I have or are they already the right size and you only have to press it in the right way.

_________________
Find a job you love and you will never have to go to work !

I would like the true answer to this too.
I believe that all 'new' bearings have a special coating/lining on them that means this process is not required (unlike older technology bearings), but would like confirmation of this!

No, unless they have not gone in straight. They're provided pre-finished.

There's only a small amount of clearance to stuff up, and it is easy to distort them as they go in without the proper tool. Then you need to have them honed/scraped to fit to the right running clearance.

Too much farting around. I let the engine machinist put them in for me, and then test the cam when I pick it up.

_________________
SooperDooperMiniCooperExpertEngineering

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

About 25 years ago I watched a reputable engine reconditioner resize the cam bearings by hammering the camshaft in.