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MAN Energy Solutions

5G70ME-LGIM9.6

Name: MAN Energy Solutions 5G70ME-LGIM9.6
Brand: MAN Energy Solutions
SKU: OSE-38371

The MAN 5G70ME-LGIM9.6 is a 5‑cylinder, low‑speed 2‑stroke main engine delivering up to 34 350 kW at 91 rpm, featuring Tier III compliant emissions and dual‑fuel capability with high‑pressure methanol injection.

34350.0 kW

Power

Engine Specifications

Cylinders

700 mm

Bore

3256 mm

Stroke

34,350 kW

MCR Power

91.0 rpm

MCR RPM

2-stroke

Stroke Type

Family: MAN Energy Solutions ME-LGIM · Tier: Tier III · Fuel: HFO, VLSFO, MDO, Methanol

Inspector Detail ✓ verified

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Designation decoded

5-cylinder MAN Green Ultra-Long-Stroke two-stroke main engine, 700 mm bore, electronically controlled (ME), methanol liquid injection (LGIM), Mark 9.6

Background

The 5G70ME-LGIM9.6 is a high-power dual-fuel engine of the Green Ultra-Long-Stroke series with a 700 mm bore and 3256 mm stroke (S/B 4.65) for methanol liquid injection. The ultra-long stroke optimizes thermal efficiency in the slow-steaming range. The 5-cylinder arrangement requires careful torsional vibration analysis and a robust torsional vibration damper.

Calculated metrics

Stroke To Bore Ratio

4.65

Mean Effective Pressure Bar

21.0

Inspector checklist

Running gear & tribology

Measure cylinder liner wear over the entire stroke length — for the G70 with a 3256 mm stroke, pay particular attention to even lubrication
BN25 cylinder oil: verify dosing rate and distribution for methanol operation
Cold corrosion check: inspect running surface condition for corrosion patterns
Inspect piston rings, piston crown, and piston rod for wear and crack formation
Check stuffing box and scavenge space for oil carry-over and deposits

Methanol injection system

Check methanol injection valves for tightness at 600-700 bar — TOXIC and a fire hazard
Inspect valve seats and needle nozzles for wear
Check seals for methanol compatibility
Check pilot fuel valves
Inspect high-pressure lines and pressure-holding valves

Methanol supply system

Check double-walled piping for integrity
Check high-pressure pumps for wear and internal leakage
Verify filters, pressure control, and safety valves
Inspect tank inerting and ventilation system
Check methanol bunker lines and shut-off valves

Safety systems

Calibrate methanol detectors — installed near the floor
Test flame detectors (UV/IR) — methanol flame is invisible
Check ventilation in protected spaces
Test ESD and quick-closing valves
Verify PPE, emergency showers, and eyewash stations

Electronic control

Check FIVA valves for function
Document EICU software version and LGIM parameter sets
Test diesel/methanol changeover
Calibrate cylinder pressure monitoring
Verify safety logic and alarm lists

Logbook reference values

Parameter	Expected	Deviation means
Exhaust temperature after cylinder (methanol)	320-390 °C	Deviations indicate combustion or injection problems
Exhaust temperature after cylinder (diesel)	350-420 °C	Check cylinder unevenness >15 °C
Methanol injection pressure	600-700 bar	Pressure drop indicates pump wear or valve problems
Pilot fuel share	3-8%	Increased share indicates methanol ignition problems
Pmax	±2 bar between cylinders	Check unevenness
Cylinder oil dosing rate (BN25)	0.6-0.8 g/kWh	Adjustment to operating profile required
Cooling water temperature	80-95 °C	Too low = cold corrosion risk

Common Failure Modes

Methanol injection valve leakage

Symptoms: ['Methanol odor', 'Leak alarm', 'Uneven exhaust temperatures', 'Pressure drop']

Causes: Valve seat wear, Seal incompatibility, Cavitation, Maintenance errors

Preventive: Leak-tightness testing per manufacturer intervals, methanol-compatible materials, calibrate detectors

Seal degradation

Symptoms: ['O-ring swelling', 'Flange leaks', 'Coating damage']

Causes: Incompatible elastomers, Chemical attack by methanol

Preventive: Follow material compatibility list, verify after maintenance

Cold corrosion

Symptoms: ['Increased liner wear', 'Ring wear', 'Rough running surfaces']

Causes: Low cooling water temperature, Insufficient BN25 dosing, Low-load operation

Preventive: Cooling water >80 °C, adjust cylinder oil, check Alpha Lubricator

Fire due to methanol leakage

Symptoms: ['Flame detector alarm', 'Increased vapor concentration', 'Almost invisible flame']

Causes: Leaking connections, Double-wall failure, Maintenance errors

Preventive: Check double-wall integrity, ensure ventilation, test flame detectors

Expert tips

💡 For the G70 with a 3256 mm stroke, pay particular attention to even cylinder oil distribution over the entire liner length — under-supply in the upper stroke region is a common problem
💡 Methanol vapor is heavier than air — check detectors near the floor; given the size of this engine, ensure a sufficient number are installed
💡 Low methanol viscosity: verify high-pressure pump delivery rate and pressure build-up at every inspection

Related components

Torsional vibration damper (5-cylinder torsional vibration risk) Methanol high-pressure pumps and pressure accumulator Double-walled lines and leak monitoring Pilot fuel system Flame and gas detectors Inert gas system Scavenge air duct and auxiliary blower Turbocharger and charge air cooler Main bearings and crankshaft (high inertial forces in the G-type)

Classification & regulatory

IMO MSC.1/Circ.1621 and the IGF Code (MSC.391(95)) for methanol safety. Classification rules and flag state regulations must additionally be observed. Toxicity management, fire protection (flash point 12 °C), and environmental protection are core topics.

Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.