6S70ME-C8.5

Common issues

• Fuel injection valve nozzle coking and wear, especially with varying fuel qualities (HFO/VLSFO) and slow steaming operations.
• Exhaust valve burning, seat wear, and spindle seizure due to high temperatures, corrosive elements in fuel, and improper timing/sealing.
• Cylinder liner wear and scuffing, particularly at the top ring reversal point, exacerbated by varying fuel sulfur content and lube oil selection.
• Issues with the Hydraulic Power Supply Unit (HPSU) and Fuel Injection Valve Actuators (FIVA valves) leading to control problems or misfires.
• Turbocharger fouling (compressor and turbine sides) and bearing wear, impacting engine efficiency and performance.
• Piston ring breakage or excessive wear, leading to blow-by, increased lube oil consumption, and scavenge space deposits.
• Scavenge space fires or excessive carbon/oil accumulation due to poor combustion or piston ring issues.
• Sensor failures (e.g., temperature, pressure, speed, position sensors) within the ME-C control system leading to alarms or derating.

Inspection checklist

• **Visual Inspection for Leakages**: Check all high-pressure fuel lines (double-walled integrity), lube oil lines, cooling water lines, and hydraulic lines for any signs of leakage. Pay attention to spray shields.
• **Scavenge Space Condition**: Inspect scavenge drains for proper flow and quality. Open scavenge ports (if accessible) to visually check cylinder liner surface, piston crown, and ring pack for excessive carbon deposits, scuffing, or blow-by.
• **Exhaust Gas System**: Monitor exhaust gas temperatures per cylinder (deviation check). Inspect turbocharger for abnormal noises, vibrations, and check bearing play (if possible during stop). Look for signs of fouling on compressor/turbine blades.
• **Fuel Injection System**: Check fuel injection valve cooling water flow/temperature. Listen for abnormal noises from FIVA valves or fuel pumps. Monitor fuel rail pressure and HPSU pressures.
• **Crankshaft Deflection**: Perform regular crankshaft deflection measurements and compare with previous records and manufacturer's limits to detect bearing wear or hull distortion.
• **Lube Oil System**: Check main lube oil pressure and temperature. Inspect lube oil filters for differential pressure. Verify sump tank level and condition of oil mist detector.
• **Cooling Water System**: Monitor jacket cooling water and charge air cooling water pressures and temperatures. Check expansion tank levels and water quality.
• **Engine Control System**: Verify all alarms and safety functions are operational. Check HPSU pressures and VCU (Valve Control Unit) status. Review alarm logs for recurring issues.
• **Engine Room Cleanliness & Safety**: Assess overall engine room cleanliness, insulation integrity on hot surfaces, condition of guards on rotating machinery, and accessibility of emergency stops.

Service intervals

Typical wear limits

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

Critical spares

• Fuel Injection Valve (complete unit, at least 1-2 per cylinder type)
• Exhaust Valve Spindle and Seat (at least 1 set)
• Piston Rings (complete set for at least 1 cylinder)
• Cylinder Liner O-rings/Seals (complete set for at least 1 cylinder)
• Turbocharger Bearing Cartridge (or complete rotor, depending on vessel's operational profile)
• HPSU Pump Elements and Seals (for hydraulic power unit)
• FIVA Valve (Fuel Injection Valve Actuator) or equivalent control components
• Assorted Gaskets, O-rings, and Seals for common maintenance tasks (e.g., indicator cocks, relief valves, fuel/lube oil filters)
• Critical Sensors (e.g., crank position, speed, exhaust gas temperature, pressure transducers)

Safety

• **Crankcase Explosion Risk**: Ensure oil mist detector is functional and calibrated. Verify crankcase relief valves are free and clear. Investigate any hot spots or abnormal bearing temperatures immediately.
• **High Pressure Fuel Oil Leaks**: The ME-C system operates with very high fuel pressures. Ensure all double-walled piping is intact, spray shields are correctly fitted, and any leaks are addressed immediately to prevent fire hazards.
• **High Temperature Surfaces**: Exhaust manifold, turbocharger casing, and other hot components must have intact insulation to prevent burns and reduce fire risk from fuel/oil impingement.
• **Rotating Machinery**: Ensure all guards for the flywheel, turning gear, and turbocharger are in place and secure to prevent entanglement injuries.
• **High Pressure Hydraulic Oil**: The HPSU system operates with high hydraulic pressures. Leaks can cause severe injection injuries. Always depressurize before working on the system and use appropriate PPE.

Class survey

Class surveyors will typically focus on the engine's overall condition, maintenance records, and the functionality of safety and control systems. Key checks include: review of logbooks, PMS records, lube oil analysis reports, and fuel oil bunkering records; witnessing crankshaft deflection measurements; functional testing of overspeed trip, emergency stops, and other safety devices (e.g., low lube oil pressure, high cooling water temperature trips); visual inspection of cylinder units via scavenge ports (and potentially opening a unit based on hours/condition); inspection of main/crankpin/crosshead bearings (selected units based on hours/condition); verification of fuel oil system integrity (double-walled piping, spray shields); turbocharger inspection for bearing play and general condition; and overall engine room cleanliness and compliance with safety regulations.