7G70ME-GI10
The MAN 7G70ME-GI10 is a 7‑cylinder, low‑speed two‑stroke main engine delivering 48 MW at 91 rpm, featuring high‑pressure LNG gas injection and instant dual‑fuel switching between HFO/VLSFO/MDO and LNG.
Engine Specifications
Inspector Detail
✓ verified
▸
Designation decoded
{'7': 'Number of cylinders: 7', 'G': 'Green ultra-long-stroke – stroke/bore ratio approx. 4.65', '70': 'Cylinder bore 700 mm', 'ME': 'Electronically controlled two-stroke engine (MAN Electronic)', 'GI': 'Gas Injection – high-pressure gas injection (approx. 300 bar, diesel cycle)', '10': 'Design version / Mark number 10'}
Background
The 7G70ME-GI10 is a powerful green ultra-long-stroke two-stroke engine with 700 mm bore for large LNG-powered ships such as Suezmax tankers, large container ships and LNG carriers. The G series with 3256 mm stroke offers optimal propeller matching at the lowest speeds. The 7-cylinder configuration requires particular attention to torsional vibration.
Calculated metrics
Inspector checklist
- Cylinder liners at 700 mm bore and ultra-long-stroke (3256 mm) – increased thermal and mechanical stress from the extremely long stroke
- Check piston rings for wear, end gap and gas blow-by formation – high piston speed in the mid-stroke range
- Inspect piston crown for erosion, thermal crack formation and condition of gas sealing surfaces
- Alpha Lubricator – BN25 dosing correctly set in gas operation, BN40-70 in diesel operation
- Document running surface pattern – observe G-type-specific wear patterns at 700 mm bore
- Check ELGI gas injection valves for tightness at 300 bar and correct switching behaviour
- Inspect double-wall piping system for integrity, leaks and corrosion
- Evaluate HP compressor – operating data, vibrations and oil quality
- Check sealing oil system – pressure, consumption and oil quality at the gas valves
- Test safety valves, emergency shutdowns and Master Gas Fuel Valve
- FIVA valves – check response behaviour, hydraulic tightness and wear
- HPS/HCU – check system pressure, oil level, filters and accumulator charge pressure
- EICU – compare fault memory, software version and current service letters
- Calibrate cylinder pressure sensors – long expansion phase on the G-type requires precise measurement
- Test gas/diesel switchover logic and all safety interlocks
- Turbocharger – larger units at 700 mm bore, check bearings, seals and vibration behaviour
- Compare exhaust temperature profiles gas vs. diesel and assess cylinder balance
- Inspect charge air cooler for fouling, corrosion and condensate drainage
- Check scavenge air duct for deposits
- Crosshead bearing – significantly increased loading from ultra-long-stroke (3256 mm) at 700 mm bore
- Check crosshead pin and guide rails for scoring marks and wear
- Check stuffing box for gas tightness – safety-critical in ME-GI operation
- Oil scraper rings and telescopic pipe seals – increased mechanical loading from long stroke
- Check torsional vibration damper for condition, oil level and temperature
- 7-cylinder G-type – combination of lowest speed and 7-cylinder vibration risk particularly critical
- Compare vibration measurements with manufacturer reference values
- Document and strictly observe the barred speed range
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Gas injection pressure | 280–320 bar | Pressure drop indicates HP compressor degradation or valve leakage |
| Exhaust temperature after cylinder (gas operation) | 340–420 °C | Spread >50 °C between cylinders indicates uneven gas distribution |
| Exhaust temperature after cylinder (diesel operation) | 360–440 °C | Individual deviation indicates injector nozzle or exhaust valve problem |
| Pmax (firing pressure) | 145–170 bar (load-dependent) | Low Pmax in gas operation indicates ignition problems or pilot oil fault |
| Pilot oil share | 3–8% of total energy | Increased consumption indicates ignition problems in gas operation |
| Cylinder oil dosing | 0.6–0.8 g/kWh (gas operation) | Incorrect setting leads to scale deposits or increased wear |
| Scavenge air pressure | 2.2–3.6 bar (load-dependent) | Low pressure indicates turbocharger degradation or cooler fouling |
| Torsional vibration amplitude | Per manufacturer specification (7-cylinder G-type) | Exceedance requires immediate inspection of the vibration system |
Common Failure Modes
Expert tips
- 💡 The 7G70ME-GI10 combines three risk factors: 7-cylinder torsional vibration, G ultra-long-stroke and large bore. Torsional vibration damper, barred speed range and crosshead bearing require the highest attention during inspection.
- 💡 Use BN25 cylinder oil in gas operation – the cold corrosion risk is particularly high on the G-type due to lower combustion temperature. Monitor Alpha Lubricator dosing closely.
- 💡 Methane is lighter than air – at 700 mm bore the gas volumes are substantial. Regularly calibrate gas detectors at ceiling level, in double-wall spaces and the crank space, and document function testing.
Related components
Classification & regulatory
['IMO Tier II – NOx emission limits, Tier III achievable with EGR or SCR', 'IGC Code – mandatory requirements for gas fuel systems on ships', 'SOLAS Chapter II-1 – fire protection and safety requirements for dual-fuel installations', 'MARPOL Annex VI – SOx/NOx emission limits, LNG operation significantly simplifies ECA compliance', 'Classification society – 7-cylinder G-type special conditions and torsional vibration approval mandatory']
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 36
Components & Design
Component data being added…
Technical Data
🤖 Ask about this model
One free question — answered like a marine engineer. No account needed.
Suppliers & Spare Parts
Direct links to manufacturer, datasheet, spare-parts portal and dealers — request access below.
📄 Request sourcing links & documentsCases, daily reports, timesheets and AI troubleshooting in the OceanSphere Marine app — free for 14 days.
Start free trial →Find manufacturers, repair shops and spare-part dealers in the Maritime Network — our global company directory.
Maritime Network →