6L28HX

Common issues

• Injector nozzle fouling and carbon build-up, leading to poor atomization and increased fuel consumption, especially with HFO.
• Exhaust valve seat wear and burning, often exacerbated by high exhaust temperatures, poor fuel quality, or incorrect valve clearances.
• Turbocharger compressor and turbine fouling, reducing efficiency and leading to higher exhaust back pressure and engine temperatures.
• Cylinder liner wear (scuffing, bore polishing) and ovality, impacting piston ring sealing and increasing lube oil consumption.
• Piston ring sticking or breakage due to carbon deposits or excessive wear, leading to blow-by and reduced compression.
• Fuel injection pump plunger and barrel wear, causing reduced injection pressure and timing issues.
• Main and crankpin bearing wear, indicated by abnormal noise, increased lube oil temperature, or metal particles in oil analysis.
• Cooling system issues, such as heat exchanger fouling or pump wear, leading to inadequate cooling and potential overheating.

Inspection checklist

• Visual Inspection: Check for any fuel, lube oil, cooling water, or exhaust gas leakages from pipes, flanges, and engine components. Look for signs of corrosion or loose fastenings.
• Engine Room Cleanliness: Assess general cleanliness, particularly around fuel and lube oil systems, indicating good housekeeping and leak management.
• Gauge Readings: Verify all critical parameters (lube oil pressure/temperature, cooling water pressure/temperature, exhaust gas temperatures per cylinder, turbocharger RPM/boost pressure, fuel pressure) are within normal operating ranges. Note any significant deviations.
• Exhaust Gas Appearance: Observe exhaust stack for abnormal smoke (black, white, blue), which can indicate combustion issues, water ingress, or excessive lube oil burning.
• Turbocharger Condition: Listen for abnormal noises (whining, rubbing), check for excessive vibration, and inspect air filter cleanliness. Note any oil leaks from bearings.
• Fuel System Integrity: Inspect fuel filters for clogging, check fuel pumps for leaks, and visually inspect injector connections for signs of leakage or carbon build-up.
• Lube Oil System: Check lube oil levels, inspect filters, and review recent lube oil analysis reports for wear metals, TBN, and water content.
• Alarm and Safety Devices: Verify alarm panel is clear, and test critical safety shutdowns (e.g., overspeed, low lube oil pressure, high cooling water temperature) if practical and approved by vessel management.
• Maintenance Records Review: Cross-reference engine running hours with planned maintenance system (PMS) for recent service on injectors, valves, turbocharger, and cylinder units. Check for outstanding defects or deferred maintenance.

Service intervals

Typical intervals for this design class, not the manufacturer’s figures for your model. The manufacturer’s manual is binding.

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 Assembly (or nozzle tips, needle valves)
• Exhaust Valve Spindle and Seat Ring (or complete valve assembly)
• Piston Ring Set (for at least one cylinder)
• Cylinder Head Gasket (at least one set)
• Fuel Injection Pump Plunger and Barrel
• Main and Crankpin Bearing Shells (at least one set of each)
• Assorted O-rings, Gaskets, and Seals (especially for cylinder head, fuel system)
• Fuel and Lube Oil Filters (primary and secondary elements)

Safety

• High-Pressure Fuel Leaks: Potential for spray fires, especially with HFO. Ensure all high-pressure fuel lines are shielded and leak-off systems are intact.
• Hot Surfaces: Exhaust manifold, turbocharger, and other engine components operate at high temperatures. Ensure insulation and guarding are in place to prevent contact burns.
• Rotating Machinery: Crankshaft, flywheel, turbocharger, and pumps pose entanglement hazards. Ensure all guards are securely fitted before engine operation.
• Crankcase Explosions: While rare, potential for crankcase explosion due to hot spots and oil mist. Ensure crankcase relief valves are functional and regular oil mist detector checks are performed.
• Noise Levels: Engine room noise can exceed safe limits. Ensure hearing protection is worn and noise abatement measures (insulation, lagging) are maintained.

Class survey

A class surveyor will typically focus on verifying the engine's structural integrity, operational safety, and adherence to classification rules. Key checks include: Review of engine maintenance records (PMS compliance, defect reports, running hours). Verification of crankshaft deflection readings (usually taken annually). Spot checks of bearing clearances during scheduled overhauls. Inspection of safety devices (overspeed trip, low lube oil pressure shutdown, high cooling water temperature shutdown, emergency stops). Integrity of fuel oil system (leakage prevention, fire insulation, quick closing valves). Condition of exhaust gas system (insulation, expansion bellows). General cleanliness and condition of the engine and associated systems. Confirmation of spare parts inventory as per class requirements. Verification of oil mist detector functionality (if fitted). Witnessing of engine trials and load tests if required after major repairs or overhauls.

Estimated lifetime: 30,000 - 50,000 hours before major overhaul, with proper maintenance and component replacement, total engine life can exceed 80,000 - 100,000 hours.