0.50 YAMAHA SEGMENT KIT

Function and technical context

Piston rings are critical elements of the combustion and lubrication system that ensure the tightness of the explosion chamber during the compression and delivery cycle. These metal rings are housed in the grooves of the piston and seal the space between the cylinder liner and the piston head, preventing combustion gases from escaping into the crankcase and preventing lubricating oil from passing into the combustion chamber. Wear or breakage of the segments causes loss of compression, entry of gases into the lubrication system, reduction in engine power and increased fuel and oil consumption.

When to replace this part?

The +0.50 mm oversize is installed when the cylinder liner has been ground after excessive clearances, internal scratches or cylinder erosion have been detected. Symptoms requiring replacement include: white or bluish smoke in the exhaust, visible loss of compression diagnosed by pressure gauge, abnormal increase in oil consumption, or roughness and wear marks on the inner surface of the cylinder during a borescope inspection. It is recommended to replace the rings during any cylinder grinding intervention and, as a preventive measure, in engine overhauls after engines with a high number of operating hours. Early replacement prevents severe navigation breakdowns and prolongs the useful life of the engine.

Equivalent manufacturer part numbers