MX5 black spark plug?

[mx5 shaun]

Hi I have a 1992 eunos roadster and its done over 200,000km I brought it as a project thinking the valve stem seals were gone I have since given the car a top end rebuild and replaced the valve stem seals and all the gaskets around the area. It was still smoking when I did the first start but after awhile of letting it warm up it didnt smoke as much and only smoked when put under load or heavy acceleration. Today I have had number 1 spark plug out to check and the plug was very black and a little wet aroung the edge, however the tip of the spark plug was not very black at all. Does anybody know what could be the problem, and do you think that the piston rings or oil scraper ring could be gone, and if the rings are gone how much would you say its goin to cost about to get another engine and get it fitted as I am not confident enough to do a engine change.

Thanks shaun

[MotorsportTom]

If the plug is wet surely it's over fuelling rather than rings?

What colour is the smoke? Does the colour change?

Is it the same with all plugs or just one of them?

[ch427]

New or old plugs?