Common Causes and Symptoms of Piston Ring Failures



Piston rings seal between the piston and the cylinder wall, preventing pressured combustion gases from entering the engine’s oil sump. Moreover, they help manage oil consumption by preventing excessive oil from entering and burning in the combustion chamber. Rings that are correctly functioning are critical to achieving optimum engine power and efficiency and having the best diesel power performance. They are in charge of pushing securely against the cylinder wall and closing the combustion chamber, preventing combustion gases from entering and oil from exiting the combustion chamber.

Oil is scraped from the cylinder wall by the oil ring as it travels down the cylinder, depositing the oil back into the oil sump throughout the process. A very thin coating of oil lubricates the contact between the rings. The cylinder wall means that it is typical for some oil to burn during combustion. What constitutes “normal” oil usage, on the other hand, varies from engine to engine. Worn rings can enable a gap to develop between the face of the ring and the cylinder wall. A blow-by may occur when compressed gases are used to move the piston down and spin the crankshaft pass by the piston and flow down the cylinder wall and into the sump, reducing horsepower and efficiency resulting from the blow-by. Blow-by also contaminates the engine oil, resulting in a reduction in its performance and useful life.

The same thing might happen if your rings become stuck together. Extremely high combustion gases may cause oil to break down, resulting in carbon deposits in the ring grooves of the piston. The byproducts of gasoline combustion may also form deposits. The detrimental consequences of faulty piston rings are often visible and noticeable. Hard starts and lower horsepower are also possible due to worn or jammed rings. The piston compresses the fuel or air combination before the spark plug ignites it when the engine is rotating over. On the other hand, bad rings enable some fuel and air to escape from the combustion chamber, lowering engine compression and making it more difficult to start the engine. Once your engine is up and going, decreasing compression causes it to lose power.

To know more about common causes and symptoms of piston ring failures, below is an infographic from Pure Diesel Power.