6H35/40

Common issues

• Cylinder cover wear and surface corrosion, requiring regular reconditioning due to marine environment and combustion stresses.
• Exhaust valve burning or seat wear, particularly when operating on HFO, due to high temperatures and corrosive combustion products.
• Fuel injector nozzle choking, erosion, or carbon build-up, impacting spray pattern and combustion efficiency, especially with Common Rail and HFO.
• Piston ring wear, breakage, or sticking, leading to increased blow-by, reduced compression, and lube oil consumption.
• Cylinder liner scuffing or cavitation erosion, often linked to cooling water quality or inadequate lubrication.
• Turbocharger fouling (compressor/turbine side) or bearing wear, leading to reduced engine efficiency and potential surge.
• Common Rail system component wear (e.g., high-pressure pump elements, pressure limiting valves) due to high operating pressures and fuel quality variations.
• Main and connecting rod bearing wear, often indicated by increased lube oil consumption, metal particles in oil, or abnormal vibrations.

Inspection checklist

• Visual inspection for fuel, lube oil, and cooling water leaks from engine block, piping, and connections.
• Check exhaust gas temperatures for individual cylinders (deviation > +/- 30°C from average indicates combustion issues).
• Measure crankcase pressure and observe oil mist detector readings for signs of blow-by or potential hot spots.
• Collect lube oil samples for analysis (wear metals, TBN, viscosity, water content, fuel dilution).
• Inspect turbocharger for axial/radial play, cleanliness of compressor and turbine, and air filter condition.
• Verify proper operation and integrity of the Common Rail fuel system, including high-pressure lines, sensors, and pressure limiting valves.
• Check all safety devices (overspeed trip, low lube oil pressure shutdown, high cooling water temperature alarm/shutdown) for functionality.
• Monitor engine vibration levels and listen for abnormal noises from bearings, gears, or valve train.
• Inspect cooling water system for leaks, proper pressure, and temperature, and check expansion tank level/condition.

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 set of fuel injector nozzles (Common Rail type)
• Exhaust valve spindles and seats (at least one set per cylinder)
• Piston rings (at least one complete set per cylinder)
• Cylinder head gaskets and O-rings
• High-pressure fuel pipe for Common Rail system (at least one spare)
• Lube oil filter elements and fuel filter elements
• Turbocharger bearing cartridge or repair kit
• Main and connecting rod bearing shells (at least one set)

Safety

• High-pressure fuel leaks from the Common Rail system can atomize and ignite, posing a severe fire hazard.
• Crankcase explosions due to oil mist ignition from hot spots or excessive blow-by; ensure oil mist detector is functional.
• Hot surfaces (exhaust manifold, turbocharger, uninsulated piping) pose burn risks and potential fire ignition points for leaked fuels/oils.
• Rotating machinery (flywheel, coupling, turbocharger) presents entanglement and impact hazards; ensure guards are in place.
• High noise levels in the engine room require hearing protection to prevent permanent hearing damage.

Class survey

For this IMO Tier III certified HiMSEN 6H35/40 engine, class surveyors will typically focus on: 1. Verification of Planned Maintenance System (PMS) records and compliance with manufacturer's recommendations. 2. Functional testing of all engine safety devices (overspeed, low lube oil pressure, high cooling water temperature, oil mist detector, remote shutdown). 3. Inspection of crankcase internals (spot checks on bearings, crankshaft, cleanliness) and verification of oil mist detector calibration. 4. Opening and inspection of selected cylinder units (piston, liner, cylinder head, exhaust valve) to assess wear and condition. 5. Integrity check of the Common Rail fuel system, including high-pressure lines, pumps, and injectors, for leaks or damage. 6. Assessment of exhaust gas emissions monitoring system (if fitted for Tier III compliance) and associated documentation. 7. Inspection of turbocharger, charge air cooler, and exhaust gas system for leaks, fouling, and insulation integrity. 8. Review of engine performance data, lube oil analysis reports, and fuel oil quality records. 9. Verification of engine's Type Approval (2013 by 9 classification societies) and compliance with all applicable statutory regulations.