Spark Plug Thread Repair (For Free!)

[Vintage Engine Repairs]

I’ve seen chasing threads with a modified spark plug, but never cutting new ones. It worked awesome:

 

[pioneerguy600]

Cool, thanks for putting up the vid. You should come over and make a vid when I am setting up a cylinder with an angled sparkplug drilling it out for an insert.

 

[Wood Doctor]

I have just a quick thought. Before doing all this machine work, I would have tried two or three other spark plugs to see if they also would not tighten down. I have already run into this and found that the plug was at fault and that another one screwed down tightly and fixed the problem. Hours of hard work might have been saved.

 

[Vintage Engine Repairs]

I have just a quick thought. Before doing all this machine work, I would have tried two or three other spark plugs to see if they also would not tighten down. I have already run into this and found that the plug was at fault and that another one screwed down tightly and fixed the problem. Hours of hard work might have been saved.

Thanks for the suggestion, I certainly agree, though I didn’t have any spare m10 plugs - If the threads weren’t too bad I could have just chased them, but these were beyond any of that. This will be sold too, so I’d rather have peace of mind that they are solid and won’t cause the customer any issues. I’ll note that tip for future if they are m14 threads, I have a few of those plugs!