Now THAT is interesting! I had never heard of that before. Any other brands use this exact process? I know Fox pistons are sintered iron. Maybe McCoy also but neither had the extra step of the material application in the crown? Again, very interesting. I have a few Johnson engines, some of them NIB, and I'll have to remember this part.
Type at you later,
Dan McEntee
PS to add;
OK, I just read the page that Brett posted the link to, and found that McCoy pistons are more or less the same, and in a photo, both displayed some accumulations under the dome on the inside of the piston. If this is correct, what was the weak point of McCoy engines that caused them to be worn out so fast, the cylinder liner material or lack of hardness ?