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MAN Energy Solutions

6G70ME-GI10

Name: MAN Energy Solutions 6G70ME-GI10
Brand: MAN Energy Solutions
SKU: OSE-38344

The MAN 6G70ME-GI10 is a six‑cylinder, low‑speed two‑stroke main propulsion engine delivering up to 41 MW at 91 rpm, designed for dual‑fuel operation on HFO/VLSFO/MDO and LNG with high‑pressure gas injection.

41220.0 kW

Power

Engine Specifications

Cylinders

700 mm

Bore

3256 mm

Stroke

41,220 kW

MCR Power

91.0 rpm

MCR RPM

2-stroke

Stroke Type

Family: MAN Energy Solutions ME-GI · Tier: Tier III · Fuel: HFO, VLSFO, MDO, LNG

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Designation decoded

{'6': 'Number of cylinders: 6', 'G': 'Green Ultra-Long-Stroke design (highest stroke/bore ratio)', '70': 'Cylinder bore: 700 mm', 'ME': 'Electronically controlled (Man Electronic) two-stroke engine', 'GI': 'Gas Injection – high-pressure gas injection (approx. 300 bar) on the diesel principle', '10': 'Mark 10 – current engine generation'}

Background

The 6G70ME-GI10 is a Green Ultra-Long-Stroke dual-fuel engine with a 700 mm bore and 3256 mm stroke in the latest Mark 10 version. With its extreme stroke/bore ratio, the G variant offers particularly low speeds for optimal direct propeller matching. It is typically used on LNG carriers and large gas-fuelled bulk carriers.

Calculated metrics

Stroke To Bore Ratio

4.651

Inspector checklist

Running Gear & Tribology

Check cylinder liner for wear and profile changes – 700 mm bore, piston approx. 2–3 tonnes
Check piston rings for wear and breakage – Ultra-Long-Stroke means higher ring load due to long stroke travel
Inspect piston crown for thermal cracks
Verify BN25 cylinder oil in gas mode, observe switchover procedure at mode change
Document liner wear trend – G-type tends toward more favourable wear behaviour due to lower speed

High-Pressure Gas Injection System (300 bar)

Check GI valves for tightness – Mark 10 has current valve generation
Check HP compressor for vibration and oil condition
Check double-wall piping system for integrity
Verify gas injection pressure 280–320 bar
Test quick-closing valves and MGFV for response time

Electronic Control (FIVA, HPS/HCU, EICU)

Check FIVA valves for response behaviour – Mark 10 with current control
Check HPS/HCU pressures and hydraulic oil
Document EICU software version and evaluate alarm history
Verify automatic gas/diesel switchover and emergency shutdown
Check PMI system (performance monitoring) for correct function

Scavenge Air & Exhaust System

Check turbocharger condition – lower speed on G-type, adapted boost
Inspect scavenge air duct
Monitor exhaust gas temperature spread between cylinders
Check exhaust valves for condition and seat
Check exhaust gas boiler for clean combustion in gas operation

Crosshead & Stuffing Box

Check crosshead bearing for wear – high mechanical load at 3256 mm stroke
Check stuffing box for gas leakage and oil blow-by
Inspect piston rod for surface quality
Check telescopic pipes for tightness

Logbook reference values

Parameter	Expected	Deviation means
Gas injection pressure	280–320 bar	Deviation indicates compressor or valve problem
Exhaust gas temperature after cylinder (gas mode)	310–370 °C (load-dependent)	Spread >50 °C shows gas distribution problem
Exhaust gas temperature after cylinder (diesel mode)	340–410 °C (load-dependent)	Deviation >30 °C indicates injection fault
Pmax (firing pressure)	According to test protocol ±5 bar	Exceeding/falling below requires root cause analysis
Pilot fuel share (gas mode)	3–8 % of total energy	Increased consumption indicates GI fault
Cylinder oil feed rate (gas mode)	0.6–0.8 g/kWh (BN25)	Incorrect setting leads to wear or deposits
Cylinder cooling water temperature	80–85 °C	Below 80 °C risk of cold corrosion in gas mode

Common Failure Modes

HP compressor failure

Symptoms: Gas pressure drop, switchover to diesel, vibration alarms

Causes: B, e, a, r, i, n, g, , w, e, a, r, ,, , l, a, c, k, , o, f, , l, u, b, r, i, c, a, t, i, o, n, ,, , o, v, e, r, l, o, a, d

Preventive: Regular vibration analysis and oil monitoring, ensure redundancy

Gas injection valve leakage

Symptoms: Gas alarm in double-wall space, temperature spread, pressure drop

Causes: N, o, z, z, l, e, , e, r, o, s, i, o, n, , a, t, , 3, 0, 0, , b, a, r, ,, , t, h, e, r, m, a, l, , f, a, t, i, g, u, e, ,, , s, e, a, l, , w, e, a, r

Preventive: Valve replacement per OEM interval, tightness testing at every inspection

Cold corrosion in gas mode

Symptoms: Increased liner wear, abnormal drain values

Causes: S, u, l, p, h, u, r, i, c, , a, c, i, d, , c, o, n, d, e, n, s, a, t, i, o, n, , f, r, o, m, , p, i, l, o, t, , f, u, e, l, , a, t, , l, o, w, , w, a, l, l, , t, e, m, p, e, r, a, t, u, r, e, s

Preventive: Cooling water temperature ≥80 °C, BN25 oil, load management

Crosshead bearing overload

Symptoms: Increased bearing temperature, metal particles in lubricating oil, knocking noises

Causes: E, x, t, r, e, m, e, , s, t, r, o, k, e, , (, 3, 2, 5, 6, , m, m, ), , g, e, n, e, r, a, t, e, s, , h, i, g, h, , i, n, e, r, t, i, a, l, , f, o, r, c, e, s, ,, , o, i, l, , f, i, l, m, , b, r, e, a, k, d, o, w, n, , a, t, , l, o, w, , l, o, a, d

Preventive: Monitor lubricating oil temperature and pressure, limit low-load operation per manufacturer specification

Expert tips

💡 With a 3256 mm stroke and an S/B ratio of 4.65, the G70 has one of the longest strokes in this bore class – crosshead and main bearings are correspondingly more heavily loaded. Bearing wear monitoring is essential.
💡 At 700 mm bore, pistons and liners weigh several tonnes – verify adequate crane capacity and tools for onboard maintenance. Dry dock only required for main bearings and crankshaft.
💡 Compare the fleet's HP compressor failure statistics with the manufacturer – Mark 10 has improved compressor technology, but operating experience with the latest generation is still being gathered.

Related components

FGSS HP compressor Gas injection valves per cylinder Gas detectors (mounted overhead — methane lighter than air) Double-wall piping system with leak monitoring Turbocharger Pilot fuel system Master Gas Fuel Valve (MGFV) EICU and safety system Deaerating tank for cooling water

Classification & regulatory

IMO Tier II as standard; Tier III achievable with EGR or SCR. IGC Code fully applicable. SOLAS II-1 Reg. 55 for gas-fuelled machinery installations. MARPOL Annex VI: LNG practically SOx-free, approx. 25 % CO2 reduction compared to HFO. Additional notation from the classification society (e.g. DNV GF, LR GF) required.

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