Where on a normally operating engine's cylinder walls is the most wear likely to occur?

The wear on a normally operating engine's cylinder walls is most likely to occur near the top of the cylinder. This area, often referred to as the ring travel zone, is where the piston rings make contact with the cylinder wall and experience the highest pressure and friction during the compression and combustion cycles. The intense heat and pressure generated in this region, combined with the scraping motion of the piston rings, lead to increased wear over time.

The top of the cylinder is also where carbon deposits tend to accumulate as a byproduct of combustion, further contributing to wear and surface degradation. This wear can increase clearance between the piston rings and the cylinder wall, which may affect the engine's overall performance, compression, and efficiency.

In contrast, wear is less pronounced near the center and bottom of the cylinder, where piston velocity is lower and there is generally less frictional contact. Additionally, wear is not evenly distributed throughout the cylinder, as the varying operating conditions and piston movement lead to localized wear patterns, particularly in the areas where the greatest stresses occur, which is near the top of the cylinder.