8G90ME-LGIM9.6

Designation decoded

{'engine_builder': 'MAN Energy Solutions', 'type_designation': '8G90ME-LGIM9.6', 'fuel_type': 'Methanol (Liquid Gas Injection, Methanol)', 'mark_version': '9.6', 'cylinder_count': 8, 'bore_mm': 900, 'stroke_mm': 3720, 'stroke_type': 'Green Ultra-Long-Stroke (G)', 'operating_principle': 'Two-stroke crosshead engine with direct methanol injection', 'configuration': 'In-line engine, 8 cylinders'}

Background

The 8G90ME-LGIM9.6 is a Green Ultra-Long-Stroke two-stroke crosshead engine of the 90 series with direct methanol injection at 600–700 bar injection pressure. With a 900 mm bore and a 3720 mm stroke, this engine achieves a stroke-to-bore ratio of 4.133 and is among the largest marine engines in methanol operation. The 900 mm bore is at the upper end of the dry-dock class — all running gear work requires a shipyard period with corresponding crane capacity. The G design enables particularly low speeds for optimal propeller integration on large container ships and VLCCs. Methanol has a flash point of 12 °C, is toxic and attacks conventional seals. BN25 cylinder oil lubrication is required.

Calculated metrics

Inspector checklist

Logbook reference values

Common Failure Modes

Expert tips

• 💡 On the G90 with a 3720 mm stroke, pay particular attention to the crosshead shoe guide track — the very long strokes produce high side forces at the reversal points
• 💡 Methanol detection in the engine room: check sensors at hip height and near the floor — methanol vapour is heavier than air and collects in low areas and bilge spaces
• 💡 The 900 mm liners weigh several tonnes — when planning inspections, always verify the availability of suitable lifting gear and transport equipment in the engine room

Related components

Classification & regulatory

Methanol as a marine fuel is subject to the IGF Code (MSC.391(95)). As a dry-dock-class series, the 90 series requires careful coordination of inspection intervals with the classification program and shipyard planning. Flag state approval for low-flashpoint fuel (flash point 12 °C) is mandatory. SOLAS II-2 fire protection requirements in extended form. For VLCC applications, also observe ISGOTT requirements.