Do you think that there will be no carbon buildup in the little space between the plug thread and the hole? The thread in the ferrule is only 1/2″ long, and the rest is just a plain hole until it reaches the combustion chamber. Is it that way it was always made? I have not had a close look at it before, I imagined that there should be a long thread in the ferrule (under the soot). But I had a close look today and it’s like described above.