Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec Ross Racing Pistons. I have a question.

I am having some low compression ross racing pistons installed in my 3.0l and we some how managed to loss the sheets that came with the pistons. Now the pistons are larger than stock so I know they have to be fitted to the piston sleaves, but do I need to do a 1mm overboreon them? Or was it just that I need to make the sleaves larger so they will physically fit? I remember something about the pistons expanding when they get hot. Please advise.

The machine shop doing the work should measure the piston diameter at critical points and bore accordingly. Call Ross and inquire about tolorances between the piston and bore. I know that with my Diamond Racing pistons, they specify a clearance of .045" IIRC ... I would have to check the spec sheet to be sure.