Main Engine 4-Stroke · Main Engines (4-Stroke)
The MAN 9L21/31 is a medium‑speed, 9‑cylinder, common‑rail injected marine diesel engine delivering up to 1 980 kW at 1000 rpm, notable for its high power density and flexible fuel capability (MGO, HFO, biofuels and methanol retrofit).
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| item | every 1000-1500 hours for minor maintenance, every 5000-7500 hours for major maintenance |
|---|
| cylinder_liner | 0.5-1.0 mm wear limit |
|---|---|
| piston_ring | 0.2-0.5 mm wear limit |
| crankshaft_bearing | 0.1-0.3 mm wear limit |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Class surveyor typically checks for compliance with manufacturer's maintenance recommendations, proper operation and condition of critical systems, and adherence to safety regulations and standards
Estimated lifetime: 20000-30000 hours before major overhaul
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