What are the surfaces of a piston that are forced against the cylinder wall during the compression and power strokes called?

The surfaces of a piston that come into contact with the cylinder wall during the compression and power strokes are referred to as thrust surfaces. These surfaces are responsible for transferring the forces generated by the combustion of fuel to the piston and then ultimately to the crankshaft.

During the compression stroke, the piston moves downward, compressing the air-fuel mixture, and the thrust surfaces must withstand the pressure exerted by the mixture. In the power stroke, the explosion of the fuel-air mixture forces the piston back down, and again, the thrust surfaces handle the intense forces involved. The design and integrity of these surfaces are crucial for maintaining proper function and efficiency within the engine.

Other terms like support surfaces, guide surfaces, and load surfaces don't accurately describe this specific interaction between the piston and cylinder wall during these critical engine operations. While these terms may relate to engine components in different contexts, they do not capture the essence of what thrust surfaces do during operation.