5S70ME-C8.5

Common issues

• Exhaust valve burning or sticking, often due to poor fuel quality, prolonged low-load operation, or issues with the hydraulic actuator system.
• Cylinder liner wear (cold corrosion from high sulfur fuel at low load, or scuffing from inadequate lubrication/poor combustion).
• Piston ring breakage or excessive wear, leading to blow-by, increased scavenge space deposits, and potential scavenge fires.
• Hydraulic Power Supply (HPS) system malfunctions, including pump wear, accumulator issues, or filter clogging, affecting fuel injection and exhaust valve operation.
• Fuel injection valve nozzle wear or sticking, resulting in poor atomization, increased exhaust gas temperatures, and black smoke.
• Turbocharger fouling (compressor and turbine side) and bearing wear, leading to reduced engine efficiency and increased thermal load.
• Scavenge space fires, typically caused by excessive blow-by, unburnt fuel, or accumulation of combustible deposits.
• Control system sensor or actuator failures, impacting precise fuel timing, exhaust valve operation, and overall engine performance.

Inspection checklist

• Cylinder Head & Exhaust Valve Actuator: Check for fuel/lube oil/cooling water leakages, exhaust valve spindle condition (visual through indicator cock), and hydraulic actuator oil level/pressure.
• Scavenge Space: Open doors, check for cleanliness, excessive oil/carbon deposits, signs of blow-by, and condition of scavenge drains.
• Crankcase: Check oil mist detector readings, open inspection doors for visual check of main/crosshead bearings (if accessible), general cleanliness, and oil level.
• Fuel Oil System (High Pressure): Inspect high-pressure fuel pipes for leaks, securing, and condition of fuel valves. Check fuel filter differential pressure.
• Hydraulic Power Supply (HPS) Unit: Check oil level, pressure, filter condition, and signs of leakage. Monitor accumulator pressure.
• Turbocharger: Check axial/radial play (if possible), inspect compressor/turbine blades for fouling/damage, and check bearing lubrication.
• Engine Performance Parameters: Monitor EGTs (balance), cylinder oil consumption, fuel consumption, turbocharger speed/boost pressure, HPS pressure, and alarm log.
• Safety Devices: Verify functionality of overspeed trip, emergency stops, and oil mist detector alarms (if testable).

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 Injection Valve (at least 1 per cylinder, preferably 2-3 onboard)
• Complete Exhaust Valve Spindle and Seat (at least 1 unit)
• Piston Rings (complete set for at least 1 cylinder)
• HPS Pump Cartridge / Repair Kit
• Turbocharger Bearing Cartridge / Repair Kit
• Cylinder Liner O-rings and Scavenge Box Seals
• Various O-rings, gaskets, and filters for fuel, lube oil, and HPS systems
• Control system sensors (e.g., EGT, pressure, position sensors) and proportional valves/actuators

Safety

• Crankcase Explosion: Risk from overheated bearings or piston components. Ensure oil mist detector is functional and alarms are monitored.
• High-Pressure Fuel/Hydraulic Oil Leaks: Risk of fire, explosion, or severe injection injury. Inspect high-pressure lines and components regularly for integrity and leaks.
• Scavenge Fire: Risk of fire in scavenge space due to excessive blow-by, unburnt fuel, or accumulation of combustible deposits. Monitor scavenge drains and EGTs.
• Hot Surfaces & Rotating Machinery: Burns from exhaust pipes/turbocharger, entanglement with rotating shafts. Ensure guards are in place and proper PPE is used.
• Working at Height: During cylinder overhauls or inspections. Ensure proper scaffolding/platforms and fall protection equipment are utilized.

Class survey

Class surveyors typically check engine logbooks, maintenance records, lube oil/fuel oil analysis reports, and performance data. Operational tests include engine start/stop, emergency stop, and overspeed trip (if due). Visual inspection covers general condition, leakages, securing of components, and exhaust gas system. Crankcase inspection (opening doors) for main/crosshead bearings and oil mist detector function. Scavenge space inspection for cleanliness and drain condition. Often, one or two cylinder units are opened for visual inspection of cylinder liner, piston crown, and exhaust valve condition, with liner wear measurements potentially requested. Fuel oil system integrity, control & monitoring systems (including HPS unit), and associated auxiliary systems are also verified.