6S90ME-C10.5

Common issues

• Exhaust Valve Spindle Burning/Sticking: Common due to high temperatures, varying fuel quality (HFO/VLSFO), or issues with hydraulic actuation/cooling.
• Fuel Injector Nozzle Choking/Wear: High-pressure injection, HFO operation, and potential for catalytic fines can lead to poor atomization, increased fuel consumption, or misfiring.
• Cylinder Liner Scuffing/Excessive Wear: Inadequate lubrication, cold corrosion (especially with VLSFO/MGO), or scavenge fires can lead to rapid liner wear or scuffing.
• Hydraulic Power Unit (HPU) Malfunctions: As an ME-C engine, the HPU is critical for fuel injection and exhaust valve actuation. Issues with pumps, accumulators, or control valves can lead to engine derating or shutdown.
• Control System (ECS) Sensor/Actuator Failures: Electronic control relies heavily on sensors (pressure, temperature, position) and actuators. Failures can cause misfiring, poor performance, or alarms.
• Turbocharger Fouling/Bearing Wear: HFO operation leads to exhaust gas fouling, reducing efficiency. Bearing wear is also a concern over time, impacting engine performance.

Inspection checklist

• Scavenge Space Inspection: Check for signs of scavenge fires, piston ring blow-by, excessive carbon deposits, and condition of scavenge port bars.
• Crankcase Inspection: Check for abnormal noise, oil mist detector readings, cleanliness, and oil leaks. During stopped, check general cleanliness and oil condition.
• Exhaust Valve Actuator & Hydraulic System Check: Verify hydraulic oil levels, pressure, and look for leaks around actuators and HPU. Check for smooth operation during turning gear.
• Fuel Injector Condition (visual/operational): Check for leaks at high-pressure lines, listen for abnormal injection noise, and monitor exhaust gas temperatures for evenness.
• Cylinder Lubrication System: Verify proper function of lubricators, check flow rates, and ensure correct cylinder oil is being used for the fuel type (e.g., BN value matching sulfur content).
• Turbocharger Inspection: Check for axial/radial play, signs of fouling on compressor/turbine sides, and oil leaks from bearings.
• Engine Control System (ECS) Alarms & Parameters: Review historical alarms, check operational parameters (pressures, temperatures, fuel consumption) against design values.
• Foundation Bolts & Chocking: Visually inspect for loose bolts, signs of movement, or oil ingress into chocking material, especially after heavy weather or long service.

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 Unit (at least 1-2 per engine)
• Exhaust Valve Spindle & Seat Ring (at least 1 set)
• Piston Rings (at least one complete set per cylinder)
• Hydraulic Power Unit (HPU) Pump Cartridge/Seal Kit
• Critical Sensors (e.g., speed, pressure, temperature for ECS)
• High-Pressure Fuel Pipe (one set for a single cylinder)
• Cylinder Liner O-rings/Seals
• Crosshead Bearing Shells (one set)

Safety

• Crankcase Explosions: Due to oil mist ignition, requiring strict adherence to oil mist detector alarms and proper ventilation.
• Scavenge Fires: Accumulation of unburnt fuel/oil in scavenge space, especially with poor combustion or excessive cylinder oil.
• High-Pressure Fuel Leaks: Fuel oil under extremely high pressure (up to 1500 bar) can penetrate skin, causing severe injury.
• Hot Surfaces & Rotating Machinery: Risk of burns and entanglement with moving parts (flywheel, turning gear, turbocharger).
• Hydraulic Oil Under High Pressure: HPU and actuators operate at high pressures (e.g., 200-300 bar), posing a jet injury risk.

Class survey

Surveyors will focus on the functionality of safety devices and alarms (overspeed, low lube oil pressure, high cooling water temp, OMD). Crankshaft deflection measurement is often required annually or biennially. Scavenge space and crankcase inspections are critical for signs of fires or abnormal wear. Fuel oil system integrity, especially high-pressure lines and lagging, is checked for fire safety. Review of logbooks, planned maintenance records, oil analysis reports, and performance data is standard. HPU condition and proper operation of the electronic control system are key for ME-C engines.