What is the term for the clearance between the ends of the piston ring?

The term for the clearance between the ends of the piston ring is specifically known as the piston ring end gap. This gap is crucial because it allows for the thermal expansion of the piston rings and helps maintain effective sealing within the combustion chamber. The proper end gap is essential for optimal engine performance as it influences both compression and oil control.

If the end gap is too small, it could potentially lead to the rings binding in their grooves due to thermal expansion, which can cause severe engine damage. Conversely, if the gap is too large, it could lead to excessive blow-by, where combustion gases escape into the crankcase, potentially resulting in loss of power and increased emissions. Hence, understanding and managing the piston ring end gap is vital for maintaining engine efficiency and longevity.