What does the piston ring end gap refer to?

The piston ring end gap refers to the distance between the ends of the piston ring when it is positioned squarely in the cylinder bore. This gap is vital for several reasons, including allowing for the thermal expansion of the rings as they heat up during engine operation and ensuring proper sealing between the piston and cylinder wall. If the end gap is too small, the rings may bind or expand excessively under heat, leading to potential engine failure. Conversely, if the gap is too large, it can result in inefficient sealing and loss of compression.

Understanding the end gap is crucial for maintaining the engine's overall performance, as it affects combustion efficiency, oil control, and engine longevity. Therefore, it's important for technicians and engineers to measure this gap accurately during installation or maintenance to ensure optimal engine function.