8G50ME-B9.5
The MAN 8G50ME-B9.5 is an eight‑cylinder, low‑speed 2‑stroke diesel main engine delivering 24 800 kW at 127 rpm, featuring camshaft‑driven exhaust valves and electronic fuel injection for Tier III NOx compliance.
Engine Specifications
Inspector Detail
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Designation decoded
8 steht für 8 Zylinder, G für Green Ultra-Long-Stroke, 50 für 500 mm Bohrung, ME-B für elektronisch gesteuerte Kraftstoffeinspritzung mit nockenwellengesteuertem Auslassventil, 9.5 für Mark 9.5.
Background
The G50ME-B9.5 with 8 cylinders maximizes power in the 50 bore class while providing best vibration behavior. S/B 4.6 for maximum efficiency. Used in Supramax to Panamax vessels.
Calculated metrics
Inspector checklist
- Zylinderlaufbuchsen: S/B 4.6 — extrem hohe Seitenkräfte
- Piston rings: ring stability at maximum side pressure
- Alpha-Lubricator: Kalibrierung
- Kreuzkopflager: Temperatur über 8 Zylinder
- Stopfbuchse: S/B 4.6 Drainage
- Kolbenstange: Rundlauf
- ME-B: Sensoren, EICU
- Nockenwelle: Kettenlängung
- Software
- Spülluftkasten: G-Typ Öleintrag-Risiko
- Turbolader: 1-2 TC
- Abgastemperatur über 8 Zylinder
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Exhaust gas temperature per cylinder | 350–420 °C at MCR | Spread >15 °C → Einspritzung prüfen |
| Spülluftdruck | 2.5–3.2 bar | Abfall → TC/Kühler |
| Pmax | ±2 bar Zylindergleichgewicht | Abweichung → Steuerung |
| Zylinderöl-Feed-Rate | 0.5–0.8 g/kWh | Alpha-Lubricator kalibrieren |
Common Failure Modes
Expert tips
- 💡 8×G50ME-B9.5: Bestes Schwingungsverhalten aller Zylinderkonfigurationen, keine Barred Speed Range
- 💡 LDF in alpha lubricator at G-type is essential — higher feed rate at full load than at part load
- 💡 8 cylinders at 500 mm bore: piston pulling possible on board — efficient maintenance planning in 2-unit groups
Related components
Classification & regulatory
IMO Tier II. Mit EGR/SCR Tier III. EEDI-optimiert. MARPOL Annex VI — VLSFO.
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 23
Components & Design
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Technical Data
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