Broken engine piston rings! These are usually the causes.

Common causes of broken piston rings: In addition to material defects and poor machining quality, poor maintenance and assembly are the main causes.

Overlap clearance is too small.

When the overlap clearance is smaller than the assembly clearance, the piston ring heats up during operation, leaving insufficient room for metal expansion at the overlap. This causes the ends of the overlap to bend against each other and break near the overlap.

Carbon deposits in the ring groove.

Poor combustion, overheating of the cylinder wall, oxidation of the lubricating oil, or burnout can all lead to severe carbon deposits in the cylinder. Severe carbon deposits hinder ring movement, causing strong contact between the ring and the cylinder wall. Scraped lubricating oil mixes with metal chips, and the exhaust gas forms localized hard carbon deposits on the lower end surface of the ring groove. Localized hard carbon deposits on the lower surface of the piston ring can be affected by periodic gas pressure, causing the piston ring to break due to bending fatigue.

Long-term relative motion between the piston assembly and the cylinder liner can cause the cylinder liner to wear out, resulting in a slab on the upper surface of the cylinder liner. When the piston reaches top dead center, the first piston ring strikes the grinding table, breaking due to the impact.

Excessive wear of the ring groove

Excessive wear of the lower end surface of the ring groove causes it to become tilted (flared). When the piston is near top dead center, the combustion gas pressure forces the ring to press against the tilted lower end surface of the groove, causing the piston ring to distort.