What is the ring gap?

• A. The distance between the ends of the ring
• B. The height of the ring
• C. The thickness of the ring
• D. The distance between multiple rings

Answer: (A)

Ring gap is the distance between the ends of a piston ring when it forms a circle in the piston groove. That small clearance allows the ring to expand with heat and still seal against the cylinder wall. If there were no gap (or it’s too small), the ring could seize in the groove as it expands; if the gap is too large, combustion gases can blow by and reduce compression. The height and thickness describe other dimensions of the ring, and the distance between multiple rings is a different concept.