8S70ME-C8.5

Common issues

• Hydraulic Power Supply (HPS) unit malfunctions (e.g., pump wear, filter clogging, control valve issues, oil degradation leading to poor fuel injection/exhaust valve operation).
• Exhaust Valve Actuator (EVA) or spindle issues (e.g., sticking, burning, hydraulic leaks, control errors leading to poor sealing or timing).
• Fuel Oil Booster (FOB) or Fuel Injection Valve (FIV) issues (e.g., nozzle wear, leakage, control problems, poor atomization, especially with varying fuel qualities).
• Cylinder liner wear/scuffing, particularly at the top ring reversal point, exacerbated by suboptimal lubrication or fuel quality changes.
• Crosshead bearing wear due to high specific loads and potential issues with lubrication oil supply or quality.
• Turbocharger fouling (compressor and/or turbine side) and bearing degradation, leading to reduced engine efficiency and higher exhaust temperatures.
• Control system sensor or actuator failures, leading to engine derating, alarms, or unexpected shutdowns.

Inspection checklist

• **HPS Unit**: Check hydraulic oil level, pressure, filter differential pressure, signs of external leaks, and listen for abnormal pump noise/vibration.
• **Exhaust Valves**: Monitor individual cylinder exhaust gas temperatures (EGTs) for balance and trends. Inspect actuators for hydraulic leaks and listen for smooth operation.
• **Fuel Injection System**: Visually inspect high-pressure fuel lines for leaks, check fuel valve cooling system integrity, and verify fuel pressure/temperature settings.
• **Cylinder Units**: Conduct scavenge space inspection for deposits, signs of leaks (fuel/lube oil), and indicators of piston ring condition. If possible, inspect piston crown via indicator cock.
• **Turbocharger**: Check rotor free play (axial and radial), inspect air filter condition, look for oil leaks from bearings, and assess for fouling on compressor/turbine blades.
• **Crankcase**: Verify oil mist detector readings are within limits. If accessible, check for abnormal bearing temperatures and listen for any knocking sounds.
• **Performance Data Review**: Analyze engine logbook data (power, RPM, fuel consumption, EGTs, pressures, temperatures) for trends, deviations, and alarm history.
• **Safety Devices**: Verify functionality of overspeed trip, low lube oil pressure shutdown, high cooling water temperature shutdown, and emergency stop buttons.
• **Control System**: Check alarm log for recurring issues, verify sensor readings against local gauges, and test remote control functionality from bridge and ECR.

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 (FIV) unit
• Exhaust Valve Spindle and Seat (or complete unit)
• Set of Piston Rings for one cylinder
• Hydraulic Pump for HPS unit
• Set of Crosshead Bearing Shells
• Assortment of O-rings and Gaskets for fuel, hydraulic, and exhaust systems
• Critical sensors (e.g., EGT, pressure, speed, crank angle position)

Safety

• **High-Pressure Fuel/Hydraulic Leaks**: Risk of spray fires from ruptured or leaking high-pressure lines (fuel up to 1000 bar, hydraulic up to 300 bar). Ensure proper shielding and lagging.
• **Crankcase Explosions**: Potential due to overheated bearings or piston components. Verify oil mist detector functionality and monitor bearing temperatures.
• **Hot Surfaces**: Risk of burns from uninsulated exhaust manifold, turbocharger casing, and steam lines. Ensure lagging is intact.
• **Scavenge Fires**: Accumulation of unburnt fuel and lube oil in the scavenge space, especially during prolonged low-load operation or poor combustion. Regular scavenge space cleaning is vital.
• **Rotating Machinery**: Entanglement risk from flywheel, turning gear, and shafting during engine operation or improper maintenance procedures. Ensure proper lock-out/tag-out during work.

Class survey

Class surveyors typically focus on: 1. **Documentation Review**: Engine logbooks, maintenance records, lube oil analysis reports, performance reports, and alarm logs to assess operational history and maintenance adherence. 2. **Safety Devices**: Verification of overspeed trip, low lube oil pressure shutdown, high cooling water temperature shutdown, crankcase oil mist detector functionality, and emergency stops. 3. **Remote Control & Maneuvering**: Testing of bridge control, engine room control, and emergency maneuvering systems for proper response and reliability. 4. **Cylinder Units**: Witnessing cylinder liner wear measurements (if scheduled), inspection of piston crown via indicator cock, and scavenge space inspection for cleanliness and integrity. 5. **Bearings**: Witnessing opening and inspection of selected main and/or crosshead bearings (if scheduled), or verification of clearances against limits. 6. **Exhaust Valves**: Witnessing opening and inspection of selected exhaust valves (if scheduled) or verification of hydraulic pressure tests and operational integrity. 7. **Fuel & Hydraulic Systems**: Inspection of high-pressure lines for leaks, checking filter condition, and verifying pressure/temperature settings for compliance. 8. **General Condition**: Overall cleanliness of the engine room, integrity of piping, insulation, foundations, and absence of abnormal vibrations or leaks.