Piston: Application and ID

Production standard pistons are available in one grade size, identified by a J (naturally aspirated) or JT (turbocharged) ink or metal stamped on the top or bottom of the piston. Also available is a production oversize piston grade sizes for in-plant rework. Identified by an S (naturally aspirated) or ST (turbocharged) ink or metal stamped on the top or bottom of the piston.