METxxMBII

Common issues

• Bearing wear (journal and thrust) leading to rotor imbalance, increased vibration, and potential contact with casing.
• Fouling of compressor impeller and turbine blades, reducing efficiency, increasing exhaust gas temperature, and potentially causing surge.
• Oil leakage from bearing housing seals, leading to excessive oil consumption, carbon build-up on the turbine side, and potential fire hazard.
• Corrosion of compressor casing and impeller due to salt ingress, moisture, or aggressive intake air conditions.
• Nozzle ring and turbine blade erosion/damage, particularly in VGT models, impacting turbine efficiency, exhaust back pressure, and potentially causing surge.
• Actuator malfunction (for Variable Geometry Turbine models) due to carbon build-up, moisture ingress, or electrical/pneumatic control issues.
• Overspeed trip system failure or sensor malfunction, posing a critical safety risk.

Inspection checklist

• Visual Inspection: Check for oil leaks (bearing casing, drain lines), exhaust gas leaks, casing cracks, loose fastenings, and general cleanliness. Pay attention to insulation integrity.
• Performance Data Review: Monitor turbocharger RPM, boost pressure, exhaust gas temperatures (in/out), and lubricating oil pressure/temperature. Compare with baseline, manufacturer's limits, and engine load.
• Vibration Monitoring: Assess vibration levels (if sensors installed) or listen for unusual noises (e.g., rubbing, whistling, rumbling).
• Air Filter Condition: Inspect and clean/replace air filter elements as necessary to prevent compressor fouling and maintain intake air quality.
• Lubricating Oil System: Check oil level, quality (take sample if due), pressure, and temperature. Ensure all drain lines are clear and unrestricted.
• Rotor Free Play (during shutdown): If safe and accessible, check axial and radial clearances by hand, comparing to manufacturer's specified limits. Listen for rubbing during slow rotation.
• Compressor/Turbine Inspection (via ports): Visually inspect for fouling, damage (e.g., foreign object damage, erosion), or corrosion on blades and casing through inspection ports.
• Safety Devices: Verify overspeed trip functionality (review test records or witness test if required) and alarm settings. Check emergency shutdown interfaces.
• Actuator/VGT Linkage (if applicable): Check for free movement, carbon build-up, and proper operation of the variable geometry mechanism.

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 journal and thrust bearings (including sleeves and washers).
• Sealing rings (labyrinth seals, gas seals, oil seals).
• Gasket and O-ring set for overhaul.
• Lubricating oil filter elements (if external system).
• Speed sensor.
• Actuator (for VGT models) or repair kit for actuator.
• Nozzle ring (especially for VGT or high-wear applications).

Safety

• High Temperature Surfaces: Exhaust casing and turbine housing operate at very high temperatures (300-600°C), posing severe burn risks. Ensure insulation and guarding are intact.
• High-Speed Rotating Assembly: Rotor speeds can exceed 100,000 RPM. Uncontained failure (rotor burst) due to imbalance or material fatigue can cause catastrophic damage and severe injury.
• Noise Hazard: Operating noise levels are extremely high, typically exceeding 100 dB(A), requiring mandatory hearing protection in the vicinity.
• Pressurized Systems: Exhaust gas and boost air are under significant pressure. Leaks can be dangerous, and sudden depressurization during maintenance can cause injury.
• Oil Mist/Fire Risk: Oil leaks onto hot surfaces can ignite, leading to engine room fires. Ensure proper sealing and clear drain lines.

Class survey

Class surveyors typically focus on: 1. Documentation Review: Verification of maintenance records, running hours, oil analysis reports, and previous survey findings. 2. Performance Monitoring: Review of operational parameters (RPM, boost pressure, temperatures) against design values and class limits. 3. Visual Inspection: General condition of the turbocharger, absence of leaks (oil, gas), integrity of insulation, mounting security, and cleanliness. 4. Safety Devices: Confirmation of overspeed trip functionality (often by reviewing test records or witnessing a test if required), alarm settings, and emergency shutdown interfaces. 5. Compliance: Ensuring maintenance and operation adhere to manufacturer's instructions and classification society rules. 6. Accessibility: Checking that inspection ports and service points are accessible for future maintenance.

Estimated lifetime: 32,000 - 48,000 running hours before a major overhaul or replacement of the complete rotating assembly and critical static components, assuming proper maintenance and operating conditions.