FAA Powerplant Written Practice Test

On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?

1. Near the bottom of the cylinder

2. In the middle of the cylinder

3. Near the top of the cylinder

4. Evenly across all sections of the cylinder

The correct answer is: Near the top of the cylinder

The greatest amount of wear on the cylinder walls of a normally operating engine occurs near the top of the cylinder. This area experiences the highest pressure and temperature conditions during combustion, which results in increased stress and thermal expansion. The top portion of the cylinder is also where the piston reaches its highest speed during the compression and combustion strokes. As the piston moves up and down, the constant impact and heat can accelerate wear in this zone compared to other areas. Additionally, the presence of combustion deposits and oil mist can lead to greater abrasion in this section of the cylinder wall, exacerbating wear. This understanding highlights the importance of maintaining proper lubrication, cooling, and combustion efficiency to mitigate wear and prolong engine life.