As a little follow up to the UP positioning of the nozzle. The ID of the nozzle is .100" (spot on guaranteed) that's the way we have them made. Base OD on most needles is like .098" .0985" .099" depending on the needle one has, so it makes sense that if you center where the free space ID to OD is minimum, any place above that when the piston moves up, CLEARANCES WILL ONLY INCREASE, right? There should be no way for a needle to rub on anything say in the half way up position without having done so on the way up. Okay, to maybe put too fine a point on it, I got time, If say you have a needle that is straight and it's rubbing the inside of the nozzle half way up, I'd advance the theory that in the down position the needle would be wedged so tight (cuz remember the needle is fatter the farther toward the dome it gets) you couldn't get the piston to move with out a major reposition of the dome..... I certainly must have a life around here somewhere......