1. List the methods used to control piston heat expansion. Cutting horizontal slot\ Heat Dam Vertical slot or T-slot Tapered Pistons Special alloy pistons Wire wound pistons Bimetal pistons 2. Why are some piston skirts tin plated? To reduce scuffing 3. How does piston pin offset control piston slap? with an offset pin, the piston wrist pin is a little offset to one side of the piston therefore the rod is not straight up and down when the piston is at TDC or BDC. This in turn allows the crank to rotate with much less resistance giving the engine more power and speed.