The top ring is usually called the compression ring. It seals the gap between the piston and cylinder wall so pressure stays inside the combustion chamber. That pressure is what allows the engine to make power. How to Install PistonRings | Complete Step-by-Step Guide "Installing pistonrings correctly is crucial for engineperformance and longevity. Genuine SANY pistonring sets deliver superior sealing, oil control, and extended service life in the most demanding operating conditions. For complete engine reliability, install this ring set together with genuine SANY pistons, cylinder liners, and connecting rod assemblies. Learn why engines use 3 pistonrings, their functions, advantages, and how each ring contributes to engine efficiency and performance. Nowadays, the pistonringseal is really what the break in process is all about. Contrary to popular belief, pistonrings don’t seal the combustion pressure by spring tension. Ring tension is necessary only to “scrape” the oil to prevent it from entering the combustion chamber. Prevent "sticky pistons" by cleaning and lubing the pistons every time you change pads. We talk a bit about how the brake functions and walk through the clea... “While unquestionably vital to performance, the pistonring is sort of the poor stepchild of the high-performanceengine,” says Keith Jones, Technical Expert at Phoenix-based Total Seal. “They get blamed for just about everything. PerformanceEngines & Components - JEGS High Performance ….