Piston and cylinders for a Stirling engine

The piston and cylinder unit includes a piston with at least one piston ring groove (35). The spacing between the piston ring groove closest to the crankshaft and the bottom edge (43) of the piston body (41) is between 0.66 and 1.5 times the piston stroke, preferably between 0.9 and 1.1 times the piston stroke. The cylinder is made of globular gray-cast iron, and its running surface is induction-hardened.