6S50ME-B9.5
The MAN 6S50ME‑B9.5 is a six‑cylinder, low‑speed two‑stroke diesel main engine delivering up to 22 380 kW at 127 rpm, featuring camshaft‑driven exhaust valves and electronic fuel injection for Tier III emissions compliance.
Engine Specifications
Inspector Detail
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Designation decoded
6 stands for 6 cylinders, S for Super-Long-Stroke, 50 for 500 mm bore, ME-B for electronically controlled fuel injection with camshaft-controlled exhaust valve, 9.5 for Mark 9.5.
Background
The S50ME-B9.5 with 6 cylinders is one of the most popular ME-B configurations. S/B 4.0 as a proven compromise. Widely used in Handymax bulkers, MR tankers, and mid-size container feeders. 6 cylinders for balanced power and vibration behavior.
Calculated metrics
Inspector checklist
- Cylinder liners: S/B 4.0 — significant side forces, document wear
- Piston rings: Butt clearance and height wear
- Alpha Lubricator: Dosing and timing
- Crosshead bearing: Temperature across 6 cylinders
- Stuffing box: Check drainage
- Piston rod: Run-out
- ME-B control: Check sensors and EICU for function
- Camshaft: Chain elongation
- SaCoSone software
- Scavenge air box: Inspection openings
- Turbocharger: Single TC
- Exhaust temperature across 6 cylinders
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Exhaust temperature by cylinder | 350–420 °C at MCR | Spread >15 °C → check injection |
| Scavenge air pressure | 2.3–3.0 bar | Drop → TC/cooler |
| Pmax | ±2 bar cylinder balance | Deviation → control system |
| Cylinder oil feed rate | 0.5–0.8 g/kWh | Calibrate Alpha Lubricator |
| Cooling water temperature | 80–85 °C | Check deviation |
Common Failure Modes
Expert tips
- 💡 6×S50ME-B9.5 is one of the most widespread ME-B configurations — broad experience base and good service network
- 💡 ME-B allows electronic optimization of injection timing — adjust injection parameters on fuel changeover (HFO→VLSFO)
- 💡 6-cylinder S50 with S/B 4.0: Balanced configuration without particular vibration issues — standard service intervals apply
Related components
Classification & regulatory
IMO Tier II compliant. Tier III with EGR/SCR. EEDI-optimized. 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
Component data being added…
Technical Data
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