I am talking to racers that are seeing small cracks in the pistons on the bottom where the skirt joins the pin boss area. Some of these guys use Rootes blowers and some use screw blowers. The screw blower car has JE pistons and does not use a Two Step on launch. Then I have another car that is a screw blower car with JE pistons and has had them in the car for over three years and has no cracks. The cracks seem to only be appearing on the thrust side of the pistons. Anybody have any ideas as to what causes this and how to prevent it?