8S50ME-GI10
The MAN 8S50ME-GI10 is an 8‑cylinder, low‑speed 2‑stroke main engine delivering ~30 MW (29 840 kW) at 127 rpm, featuring high‑pressure gas injection for dual‑fuel operation on HFO/MDO and LNG with near‑zero methane slip.
Engine Specifications
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Designation decoded
{'8': 'Number of cylinders: 8 (best vibration behaviour)', 'S': 'Super-Long-Stroke ratio (S/B approx. 4.0)', '50': 'Bore: 500 mm', 'ME': 'Electronically controlled (MAN Electronic) two-stroke engine', 'GI': 'Gas Injection – high-pressure gas injection (approx. 300 bar, diesel cycle)', '10': 'Mark/Version 10'}
Background
The 8S50ME-GI10 is a compact Super-Long-Stroke engine with a 500 mm bore and 2000 mm stroke. The 8-cylinder configuration offers the best vibration behaviour in the series. As the smallest ME-GI engine in the portfolio, it is suitable for smaller LNG-fuelled ships, feeder container ships and special vessels where dual-fuel operation with high-pressure gas injection is desired.
Calculated metrics
Inspector checklist
- Check cylinder liners for scoring, cloverleafing and polishing
- Inspect piston rings for wear and fracture
- Check cylinder oil feed rate and BN value (BN25 in gas operation)
- Inspect piston crown for burn marks and erosion – at 500 mm bore, piston withdrawal on board is possible
- Evaluate liner wear measurements
- Check gas injection valves for tightness and coking
- Inspect high-pressure gas lines and double-wall piping system for leaks
- Check gas pressures (280–320 bar)
- Test safety valves and quick-closing valves
- Check inert gas system in the double-wall piping
- Check FIVA valves for function and response times
- Inspect HPS and HCU for leaks
- Read out EICU fault memory
- Test gas/diesel changeover
- Check all 8 cylinder control units for uniform operation
- Check turbocharger for bearing clearance and fouling
- Check scavenge air pressure and temperature
- Compare exhaust gas temperatures of all 8 cylinders – 8-cylinder should be particularly even
- Inspect charge air cooler
- Check crosshead bearing for wear
- Check stuffing box for gas blow-by and oil leakage
- Check oil scraper rings
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Gas injection pressure | 280–320 bar | Pressure below 280 bar: incomplete combustion; above 320 bar: mechanical overload |
| Exhaust gas temperature (gas operation) | 360–410 °C | Deviation >25 °C between cylinders: especially noticeable on 8-cylinder engines, check GI valve or gas distribution |
| Exhaust gas temperature (diesel operation) | 330–400 °C | Increased temperature: check injection |
| Pmax (firing pressure) | 140–170 bar | Deviation >5 bar: check injection or gas valve |
| Pilot fuel share | 3–8 % | Increased share: GI valve problems |
| Cylinder oil feed rate | 0.6–1.0 g/kWh (BN25) | Too low: wear; too high: deposits |
Common Failure Modes
Expert tips
- 💡 The 8-cylinder configuration has the best vibration behaviour – exhaust gas temperature spread should be particularly even. Deviations indicate specific cylinder problems.
- 💡 At 500 mm bore, piston withdrawal on board is possible without a dry dock, which significantly increases maintenance flexibility. The HP compressor nevertheless remains the most critical component.
- 💡 Methane is lighter than air – install gas detectors at the top of the engine room and calibrate them regularly. Use BN25 cylinder oil in gas operation.
Related components
Classification & regulatory
['IMO Tier II worldwide; Tier III in ECAs – gas operation achieves Tier III without exhaust gas aftertreatment', 'IGC Code: requirements for gas systems', 'SOLAS Chapter II-2: fire protection for gas-fuelled ships', 'MARPOL Annex VI: SOx and NOx limits']
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 36
Components & Design
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Technical Data
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