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Project

CAT 3516 Main Engine Valve Lashing & Injector Height Setting for Tugboat in India

Table of Contents

Background

Industry
Marine
Solution
Valve Lashing & Injector Height Setting
Make & Model
CAT 3516
Main Engine
Asset
Tugboat

Summary About The Project

Neptunus carried out valve lashing and injector height setting on two CAT 3516 Main Engines installed on a tugboat in India. The maintenance scope included camshaft timing verification, valve lash setting, injector height setting, CAT ET diagnostics, ECM checks, safety system testing, real-time engine parameter monitoring, sensor range verification, and injector solenoid testing. Both Main Engines had high operating hours, with the PORT Main Engine at 26,602 hours and the STBD Main Engine at 26,734 hours. During the inspection, fuel leakage was observed from multiple cylinder head plugs on the STBD Main Engine, while the coolant level gauge on the PORT Main Engine was found to be non-functional. Following the maintenance activities, both Main Engines underwent idle operation and rated RPM load trials, with all monitored parameters, safety systems, and overall performance remaining within OEM limits.

Planning

  • Team Composition: Neptunus Service Engineer with technical expertise
  • Duration: 17 September 2025 to 19 September 2025
  • Work Scope:
    Camshaft timing check, valve lash setting, injector height setting, CAT ET and ECM diagnostics, Product Status Report download, Diagnostic Trouble Code verification, safety system testing, real-time engine parameter monitoring, sensor range verification, injector solenoid testing, and post-maintenance engine trials.

Procedure Carried Out

1. Camshaft Timing Check:
  • Checked camshaft timing of both CAT 3516 Main Engines.
  • Camshaft timing was found to be satisfactory.
2. Valve Lash Setting:
  • Carried out valve lash setting on both CAT 3516 Main Engines.
  • Valve lash setting was performed in accordance with OEM guidelines.
3. Injector Height Setting:
  • Carried out injector height setting on both CAT 3516 Main Engines.
  • Injector height setting was performed in accordance with OEM guidelines.
4. CAT ET and ECM Diagnostics:
  • Connected CAT ET to the ECM using a communication adapter.
  • Downloaded the Product Status Report.
  • Retrieved and reviewed Diagnostic Trouble Codes.
  • No active diagnostic codes were found, except for the PORT Main Engine low coolant level warning associated with the defective coolant level gauge.
5. Safety System Testing:
  • Tested Emergency Stop.
  • Tested Low Engine Oil Pressure Alarm and Trip.
  • Tested High Engine Coolant Temperature Alarm and Trip.
  • Tested High Crankcase Pressure Alarm and Trip.
  • Tested Low Fuel Oil Pressure Alarm.
  • Tested High Engine Oil Temperature Alarm.
6. Engine Parameter Monitoring:
  • Monitored real-time engine parameters including RPM, coolant temperature, and oil pressure.
  • Verified monitored parameters against OEM operating limits.
  • Verified sensor operating ranges.
7. Injector Solenoid Testing:
  • Carried out injector solenoid testing on both CAT 3516 Main Engines.
  • Tested all 16 cylinders on the PORT Main Engine.
  • Tested all 16 cylinders on the STBD Main Engine.
  • All injector solenoid tests were satisfactory.
8. PORT Main Engine Inspection:
  • Recorded operating time of 26,602 hours.
  • Checked engine diagnostic information.
  • Identified a non-functional coolant level gauge.
  • Low coolant level warning was present.
  • No active diagnostic codes were found.
9. STBD Main Engine Inspection:
  • Recorded operating time of 26,734 hours.
  • Inspected cylinder head plugs.
  • Fuel leakage was found from multiple cylinder head plugs.
  • No active diagnostic codes were found.
10. Post-Maintenance Trials:
  • Operated both CAT 3516 Main Engines at idle RPM for 30 minutes.
  • Carried out safety and operational checks.
  • Subsequently operated both Main Engines at rated RPM under available load for 1 hour.
  • Monitored engine parameters, safety systems, and overall performance.
  • All monitored parameters and safety systems remained within OEM limits.

Recommendations

The O-rings of the leaking cylinder head plugs on the STBD CAT 3516 Main Engine should be replaced to prevent continued fuel leakage. The defective coolant level gauge on the PORT CAT 3516 Main Engine should be replaced to ensure reliable coolant level indication. Valve lash should be checked every 2,000 running hours thereafter, and the OEM maintenance schedule should be followed strictly.

Pre-Commissioning and Load Trials

Following the valve lashing and injector height setting activities, both CAT 3516 Main Engines were operated at idle RPM for 30 minutes to carry out safety and operational checks. The Main Engines were subsequently operated at rated RPM under available load for 1 hour. During the trials, engine RPM, coolant temperature, oil pressure, safety systems, and overall engine performance were monitored. All monitored parameters, safety systems, and engine performance remained within OEM limits.

Scope for Improvement

The inspection identified specific areas requiring attention to maintain reliable engine operation. Fuel leakage was observed from multiple cylinder head plugs on the STBD CAT 3516 Main Engine, indicating the need for replacement of the affected O-rings. On the PORT CAT 3516 Main Engine, the coolant level gauge was found to be non-functional and requires replacement to ensure accurate coolant level indication. Continued monitoring of these areas is recommended as part of the engine maintenance program

Conclusion

Neptunus carried out valve lashing and injector height setting on two CAT 3516 Main Engines for a tugboat in India. The work included camshaft timing verification, valve lash setting, injector height setting, CAT ET diagnostics, ECM checks, safety system testing, sensor verification, and injector solenoid testing. All 16 cylinders on both Main Engines showed satisfactory injector solenoid test results, while no active diagnostic codes were found. Following the maintenance, both Main Engines successfully underwent 30 minutes of idle operation and 1 hour of rated RPM operation under available load. Engine parameters, safety systems, and overall performance remained within OEM limits during the trials.

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