What is a common symptom of worn piston rings in an aircraft reciprocating engine?

The presence of blue smoke from the exhaust is a common symptom of worn piston rings in an aircraft reciprocating engine. When piston rings become worn, they are less effective at sealing the combustion chamber. This allows oil, which can seep into the combustion space, to be burned alongside the fuel-air mixture. The combustion of oil produces a distinctive blue smoke, which indicates that the engine is not operating efficiently and that oil is being consumed in an undesirable manner.

In contrast, excessive fuel consumption might occur due to a variety of other factors such as carburetor issues or incorrect mixture settings, while higher than normal oil pressure typically suggests a problem with the oil pump or blockage, rather than worn rings. Increased engine performance would not be associated with worn piston rings; in fact, worn rings would generally lead to reduced performance due to loss of compression and power. Understanding these symptoms is crucial for maintenance and diagnosing issues in reciprocating engines.