Good day gents I have a little problem with my datsun, no1 cylinder's spark plug keeps on turning black and then the engine seems to misfire, if I change the spark plug it runs well for a while and again gets worse, If changed the plug wires. any ideas
Thanks

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Is that black stuff a dry soot or an oily soot? That will help determine the problem. Also, when was the last time that the valves were adjusted?, if you have one of the exhaust valves slightly open, that could be the cause. Have you done a compression check?
Does it use an excessive amount of oil? How old are the distributor cap and rotor, or plug wires? It's hard to diagnose a problem from a picture and not many specifics. The fouled spark is a symptom of something of something else, you are going to need to do more investigation.

Yes, the fouled spark is a symptom of something of something else. Time for an Engine compression test. Also, and it might be the photo, but to me the spark plug gap looks too big. Make sure it is no larger than 0.9 mm

Thank you for the info, gents. Its more a kind of dry soot than wet oily, it's not so long ago that I'f done a compression check but can't remember the figures, no oil use keep a close eye on that, I'm not sure how old the cap is, I'f converted to a d4r dizzy with its original cap, plug leads was changed recently no more than a year ago, I'll do some checks and let you know.