7G95ME-C10.5

Common issues

• Hydraulic Power Supply (HPS) unit malfunctions: Issues with pumps, filters, or control valves leading to unstable hydraulic pressure for fuel injection and exhaust valve actuation.
• Exhaust valve burning/sticking: Due to poor fuel quality, inadequate cooling, or incorrect timing/actuation, leading to loss of compression and high EGTs.
• Cylinder liner cold corrosion/wear: Especially prevalent with VLSFO/MGO operation at low loads or insufficient cylinder oil feed rate/base number (BN).
• Fuel injector nozzle fouling/wear: Leading to poor atomization, increased fuel consumption, and higher thermal loads on cylinder components.
• Piston ring sticking/breakage: Caused by carbon deposits, poor lubrication, or excessive liner wear, affecting compression and scavenge efficiency.
• Turbocharger fouling/bearing wear: Reduced efficiency, surging, or high bearing temperatures due to exhaust gas deposits or lubrication issues.
• Scavenge space fires: Accumulation of unburnt fuel and lube oil, igniting due to hot spots or blow-by from cylinder units.
• Crosshead bearing wear: Due to insufficient lubrication, contaminated lube oil, or excessive loads, leading to increased clearances and potential damage.

Inspection checklist

• Engine room logbook review: Verify trends in EGTs, scavenge air pressure/temperature, fuel/lube oil consumption, HPS pressure, and alarm history for anomalies.
• Scavenge port inspection: Check cylinder liner condition for scoring, scuffing, or signs of cold corrosion. Assess piston crown and ring pack cleanliness for excessive carbon deposits.
• Fuel system integrity: Inspect high-pressure fuel pipes for leaks, proper shielding, and condition of fuel injectors (cooling, leaks). Verify common rail pressure stability.
• Exhaust valve actuator and system: Check for hydraulic leaks, proper operation, and balance of exhaust gas temperatures (EGTs) across cylinders. Listen for abnormal noises.
• Crankcase and scavenge space: Inspect for oil mist, water ingress, and cleanliness. Check for signs of blow-by or potential fire hazards.
• Turbocharger condition: Visually inspect compressor and turbine sides for fouling. Check bearing play (axial/radial) if accessible, and listen for unusual noises.
• Lubrication system: Verify lube oil pressures and temperatures. Inspect filters for contamination. Check sump level and condition of oil mist detector.
• Control and safety systems: Function test emergency stop, overspeed trip, and critical alarms (low lube oil pressure, high jacket water temperature). Verify HPS unit operation and pressure.
• Cooling water system: Check jacket water pressure, temperature, and cooler efficiency. Inspect for leaks or signs of corrosion.

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Complete fuel injector assembly (or nozzle tips)
• Exhaust valve spindle and seat ring
• Set of piston rings (for at least one cylinder)
• Turbocharger bearing cartridge / complete rotor assembly
• High-pressure fuel pipe (for at least one cylinder)
• Hydraulic Power Supply (HPS) unit filter elements and critical seals
• Main engine sensors (EGT, pressure, temperature)
• Start air valve assembly

Safety

• Crankcase explosion: Risk from hot spots (e.g., worn bearings, piston blow-by) igniting oil mist. Ensure oil mist detector is functional and crankcase doors are properly sealed.
• Scavenge space fires: Accumulation of oil and carbon deposits can ignite. Regular cleaning and proper cylinder lubrication are crucial.
• High-pressure fuel line leaks: Potential for spray fires. Ensure all high-pressure fuel lines are double-walled or properly shielded and leak detection systems are operational.
• Overspeed: Failure of governor or safety trip mechanisms can lead to catastrophic engine damage. Regular testing of overspeed trip is mandatory.
• Hot surfaces: Exhaust manifold, turbocharger, and other components operate at high temperatures. Ensure insulation is intact and personnel are aware of burn hazards.

Class survey

Class surveyors typically focus on verifying the engine's structural integrity, safety systems, and compliance with classification rules. Key checks include: review of engine logbooks and maintenance records (including lube oil analysis and fuel reports); functional testing of overspeed trip and emergency stop devices; crankshaft deflection measurements; inspection of scavenge spaces for cleanliness and fire prevention; opening of selected cylinder units (piston, liner, exhaust valve) for condition assessment based on running hours and previous survey findings; verification of fuel oil system integrity (high-pressure pipe shielding, leak detection); and general visual inspection for leaks, abnormal vibrations, and proper functioning of auxiliary systems. Emphasis is placed on the electronic control system's reliability and alarm management.