6LEL44

Common issues

• Fuel injector nozzle choking/wear due to HFO operation, leading to poor combustion and increased exhaust temperatures.
• Exhaust valve burning and pitting caused by high temperatures, corrosive HFO combustion products, and improper seating.
• Cylinder liner wear and cold corrosion, especially with varying loads and HFO, leading to increased lube oil consumption and blow-by.
• Turbocharger bearing wear and fouling (both compressor and turbine sides), resulting in reduced efficiency and potential surging.
• Main and crankpin bearing wear, often linked to lube oil degradation, contamination, or shaft alignment issues.
• Fuel pump element (plunger and barrel) wear, causing reduced injection pressure and timing inaccuracies.
• Governor hunting or instability, particularly with older mechanical governors, affecting engine speed control.
• Cooling water system fouling (jacket water side, coolers), leading to reduced heat transfer efficiency and potential overheating.

Inspection checklist

• Visual inspection for leaks (fuel, lube oil, cooling water, exhaust gas) from pipe joints, flanges, and seals.
• Check engine operating parameters (pressures, temperatures, RPM) against manufacturer's data and recent trends for deviations.
• Listen for unusual noises (knocking, rattling, turbocharger whine) and feel for excessive vibrations across the engine block.
• Inspect fuel oil system components: filters, heaters, pumps, and high-pressure lines for integrity and signs of leakage.
• Verify lubricating oil system health: sump level, purifier operation, and review latest lube oil analysis reports.
• Examine cooling water system: expansion tank level, pump gland leaks, cooler cleanliness (visual if possible), and proper flow.
• Inspect turbocharger: air filter condition, signs of oil leakage from bearings, compressor/turbine fouling, and axial/radial play.
• Check exhaust gas manifold and insulation for leaks, hot spots, and general integrity.
• Test local and remote emergency stop functions and overspeed trip mechanism for proper operation.
• Confirm starting air pressure and check for leaks at starting air distributor, main starting valve, and pilot valves.

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 or Nozzle Tip & Needle (at least 1 set per cylinder type)
• Piston Rings (complete set for 1 cylinder)
• Exhaust Valve Spindle & Seat Ring (at least 1 set)
• Main Bearing Shells (1 complete set)
• Crankpin Bearing Shells (1 complete set)
• Fuel Pump Plunger & Barrel (1 set)
• Turbocharger Bearing Cartridge or complete bearing assembly
• Assorted Gaskets & O-rings for cylinder head, fuel pumps, and common flanges

Safety

• High-Pressure Fuel Oil Leaks: Risk of fire or severe injury from atomized fuel spray. Ensure proper shielding and leak-off arrangements are intact.
• Hot Surfaces: Exhaust manifold, turbocharger, steam lines, and engine block can cause severe burns. Verify insulation is complete and undamaged.
• Rotating Machinery: Flywheel, crankshaft, coupling, and auxiliary drives pose entanglement risks. Ensure all guards and covers are securely in place.
• Crankcase Explosions: Potential for oil mist ignition. Verify oil mist detector functionality and crankcase relief valve integrity (flame traps).
• Starting Air System: High-pressure air can cause severe injury or uncontrolled engine starts. Check for leaks and ensure proper valve operation and safety interlocks.

Class survey

A class surveyor typically checks the overall engine condition, cleanliness, and absence of leaks. Key areas include verification of safety devices (overspeed trip, low lube oil pressure shutdown, high cooling water temperature shutdown, emergency stops), inspection of crankcase relief valves (flame traps, spring condition) and oil mist detector functionality. Crankshaft deflection readings are often required at Special Survey or intermediate surveys depending on class rules and engine age. Main and/or crankpin bearing inspections are conducted as per survey schedule (e.g., Special Survey). The integrity of high-pressure fuel lines, leak-off arrangements, and fire insulation is crucial. Functionality of starting air valves, emergency starting arrangements, and air bottle pressure are also verified. Logbook entries for engine running hours, maintenance records, lube oil analysis reports, and performance data are reviewed. Turbocharger general condition, bearing play (if accessible), and signs of surging or fouling are also noted.

Estimated lifetime: 80,000 - 120,000 running hours before requiring a major, comprehensive overhaul (e.g., crankshaft regrinding, full component replacement). With diligent maintenance, some units exceed this significantly.