6W38

Common issues

• Cold Corrosion of Cylinder Liners: Sulfuric acid formation from fuel sulfur content when liner wall temperature is below acid dew point, leading to increased wear and scuffing risk, especially during low load operation or frequent starts/stops.
• Exhaust Valve Burn-out/Wear: Common with HFO operation due to high temperatures, abrasive particles in fuel, poor fuel quality, or incorrect valve timing/seating, leading to loss of compression and performance.
• Fuel Injection System Malfunctions: Clogging of injector nozzles, wear of fuel pump elements, or timing issues due to contaminants in HFO, leading to poor combustion, increased exhaust temperatures, and potential engine damage.
• Turbocharger Fouling and Bearing Wear: Accumulation of deposits on compressor and turbine blades due to exhaust gas quality or intake air contamination, leading to reduced efficiency. Bearing wear can occur due to lubrication issues or imbalance.
• Main and Big End Bearing Wear: Can be caused by lubrication oil degradation, insufficient oil pressure, misalignment, or overloading, leading to increased clearances and potential catastrophic failure.
• Piston Ring Sticking/Breakage: Due to combustion deposits, poor cylinder lubrication, or excessive liner wear, leading to blow-by, increased oil consumption, and reduced engine efficiency.
• Cooling System Blockages/Leaks: Fouling in heat exchangers (charge air cooler, jacket water cooler) reducing cooling efficiency, pump wear, or corrosion in piping, leading to overheating or water ingress.

Inspection checklist

• Cylinder Liner Condition: Visually inspect for signs of scuffing, wear ridge at top dead center, and evidence of cold corrosion (e.g., polished areas, pitting). Measure wear if possible (e.g., using a bore gauge during overhaul).
• Exhaust Valve Condition: Check for signs of burning, pitting, or excessive carbon build-up on valve seats. Monitor exhaust gas temperatures per cylinder for significant deviations, indicating poor sealing.
• Fuel System Integrity: Inspect high-pressure fuel lines for leaks (especially at connections), check fuel filter differential pressure, and verify fuel pump rack settings and linkages for smooth operation.
• Turbocharger Inspection: Check axial and radial play of the rotor shaft, inspect compressor and turbine blades for damage or fouling, and look for oil leaks from bearing housings. Verify air filter cleanliness.
• Lubricating Oil System: Verify correct oil pressure and temperature. Check L.O. filter differential pressure. Review recent lubricating oil analysis reports for wear metals, TBN, and water content.
• Cooling Water System: Verify jacket water and charge air cooler water temperatures and pressures. Inspect for leaks, check expansion tank levels, and ensure heat exchanger cleanliness (e.g., differential pressure across coolers).
• Engine Foundation and Mountings: Visually inspect engine foundation bolts for tightness and signs of movement. Check for cracks in the engine block or foundation structure. Monitor engine vibration levels.
• Safety Devices: Verify the functionality of critical safety devices such as overspeed trip, low lubricating oil pressure shutdown, and high jacket water/exhaust gas temperature alarms/shutdowns (functional test if safe and permitted).
• General Engine Cleanliness and Leakages: Conduct a thorough visual inspection for any oil, fuel, or water leakages from pipes, flanges, seals, and covers. Ensure general engine room cleanliness around the engine.

Service intervals

Typical wear limits

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

Critical spares

• Cylinder Head Gaskets and O-rings (complete set for at least one cylinder)
• Fuel Injector Nozzles (or complete injectors, at least one set per cylinder)
• Exhaust Valve Spindles, Seats, and Rotators (at least one set)
• Piston Rings (complete set for at least one cylinder)
• Main and Big End Bearing Shells (at least one set of each type)
• Fuel Filters (primary and secondary elements)
• Lubricating Oil Filters (elements for main and fine filters)
• Various Gaskets and O-rings for common maintenance points (e.g., inspection covers, pipe flanges)
• Critical Sensors (e.g., temperature, pressure, speed sensors)

Safety

• High-Pressure Fuel Lines: Risk of spray fires from leaking HFO lines, especially in the event of a pipe rupture. Ensure proper shielding and regular inspection.
• Hot Surfaces: Exhaust manifold, turbocharger, and cylinder heads operate at very high temperatures, posing a severe burn risk. Ensure insulation is intact.
• Rotating Machinery: Crankshaft, flywheel, and turbocharger rotate at high speeds. Ensure all guards are in place to prevent entanglement.
• Confined Space Entry: Crankcase and exhaust ducts may require confined space entry procedures during maintenance, requiring gas detection and ventilation.
• High Noise Levels: Engine room noise levels are typically very high, necessitating hearing protection to prevent permanent hearing damage.
• Pressurized Systems: Cooling water, starting air, and fuel systems are under pressure, posing a risk of rupture or uncontrolled release during maintenance or failure.

Class survey

For the Wärtsilä 6W38, class surveyors typically focus on: * Annual Survey: Verification of safety devices (overspeed trip, low oil pressure, high temperature shutdowns), general condition of the engine and auxiliaries, absence of significant leakages, exhaust gas appearance, foundation bolt integrity, fire flaps, and remote control functionality. Review of engine logbooks and maintenance records is mandatory. * Intermediate Survey: As per annual, with a closer inspection of accessible parts. The surveyor may request opening of selected components (e.g., one cylinder unit, fuel pump) based on operational history, oil analysis results, or surveyor's discretion. * Special Survey (5-year): Comprehensive inspection including opening of a specified percentage of cylinder units (typically 25-33%), main and big end bearings (25-33%), turbocharger, fuel pumps, and cooling water pumps. Crankshaft deflection measurements are mandatory. Non-destructive testing (NDT) of critical components (e.g., connecting rods, crankshaft) may be required. Verification of all safety systems, alarm functions, and remote/local controls. Thorough review of all maintenance and oil analysis records. Compliance with current emissions regulations (e.g., NOx, SOx) is also checked, especially for legacy engines that may have undergone upgrades.

Estimated lifetime: 100,000 - 150,000 running hours before major engine overhaul (e.g., crankshaft removal, block line boring), assuming proper maintenance and operation.