I'm just pulling the 1275 engine out for shits and giggles and it's ten yearly freshen up with some essential maintenance stuff, a new RE13 cam and other goodies and a coat of fresh paint.

I've just noticed that some of the exhaust valve stems within the ports have a whitish ash attached to the top of valve itself, normally I wouldn't hassle over it but since I'm freshening things up....

No.1 and 2 have the white ash, No.3 is as clean as a whistle and no 4 has a brown deposit and a touch of what is obviously wet oil.

is this caused by oil coming down the guides, or from oil getting up past the rings?

Number 1:



Number 2:



Number 3:



Number 4:



Gratuitous picture of a naked rear end:

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SooperDooperMiniCooperExpertEngineering

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

The white ash or brown stuff is from fuel additives etc, the oily one I would suspect has a worn valve guide or valve stem.
Unless the combustion chamber of that one has lots of carbon too, I doubt it is rings.
Guides are cheap- I'd replace them all. And any valves that have more than .001" stem wear. Compare to the top bit that doesn't wear.

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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 wonder then why number three is so clean??

Must be time for a head off anyway, I sense a pandora's box here...

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SooperDooperMiniCooperExpertEngineering

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

A water leak into a cylinder will make that one burn clean.. check head gasket.

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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.

Okley dokley, that's all lthe excuse I needed.

Turbo head gasket's the one to use eh?

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SooperDooperMiniCooperExpertEngineering

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

Yep,,,the black one Payen P/N - BK450

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.