Strosek Ultra

Kevin, as said before all pistons are conical and oval in design. If you want to measure the pistons, measure at the skirt where the diameter is as largest at a 90 degrees angle to the wrist pin. The factory prescribes measuring at a point of 62mm below from the piston top (2-valve engine) or 50mm below the piston top (GTS) respectively. I have no other information concerning the S3 or S4 engines. If you have custom made pistons, you have to find the point of the largest diameter on your own. Above the top ring, the diameter of the piston is about 0.5 mm (.020 ") smaller. It is compensation for thermal expansion.
Åke
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