The fuel pump piston and cylinder set H 55030 is a precision-engineered assembly at the heart of the Sulzer ASL25 fuel injection system, responsible for generating the high pressures required for accurate fuel delivery. Manufactured to extremely tight tolerances, this matched pair ensures controlled fuel metering, consistent injection timing, and efficient atomization under varying engine loads. Its wear-resistant materials and finely finished surfaces minimize internal leakage and friction, supporting stable combustion, reduced emissions, and long service life in demanding marine and industrial applications.