X2 on the confusion
. If I understand your post , you said you coated the piston tops above the ring lands ... correct ? Does this mean there is ceramic not just on the piston top , but also on the sides down to the ring groves ??? That would possibly account for the added clearance , but wouldn`t the ceramic possibly crack because of the side loading ??? According to Harold , an advantage of the piston skirt coating is that it allows the builder to tighten up the clearances ( they won`t say how much ) , which in turn means the ring seal to the block is better since the pistons don`t rock in the bore as much . I realize we are talking small gains here , but all these small things add up . I also wonder if it has something to do with the prep and compounds Techline uses as the ones I have used require no increase in piston to wall clearances . If course , they may be using machinery that holds tolerances a lot better than what the average machine shop can do .
Again , everything had to be run in ( burnished ) before making pulls on the dyno .