FAA Powerplant Written Practice Test

Cylinder walls are usually lubricated by?

1. Gravity oil flow

2. Sprayed or splashed oil

3. Direct oil injection

4. Heat exchange oil

The correct answer is: Sprayed or splashed oil

Cylinder walls in an engine are typically lubricated by a method known as sprayed or splashed oil. This process involves the use of oil that is either sprayed from a nozzle or splashed up from the crankcase, allowing for effective coverage of the cylinder walls. Proper lubrication is critical as it reduces friction between moving components, minimizes wear, and dissipates heat, thereby enhancing engine efficiency and longevity. Sprayed or splashed oil can reach the cylinder walls even in areas that are not directly accessible, ensuring that oil coats the surfaces adequately. This method is particularly effective in piston engines where the motion of the pistons generates enough force to splatter the oil around, maintaining a lubricating film over the cylinder walls. Other methods of lubrication, while used in specific circumstances, do not typically provide the same broad and effective coverage as spraying or splashing oil.