This document consists of the detection and verification of a issue in the area of exhaust valves unit no 8 of a Bergen C25:33L9PY Main Engine SB with 48600 running hours. A Hi, Raw, Ultra vibration and PV measurements were performed with our equipment, the results were then analyzed.
1 INTRODUCTION
The engine condition is based on vibration and ultrasonic measurements taken. The data obtained from the engine analysis was processed, analyzed and compiled by a qualified professional analyst, resulting in the following recommendation:
Exhaust valve clearance check.
2 DEVELOPMENTS
2.1 THEORETICAL REFRENCES:
Early closing of the valve indicates a problem of excess clearance ore damage on the hydraulic tappets.
2.2 VIBRATIONS SHOWN
Exhaust valves Hi Freq Vib measurements acquired equipment can be shown as follow:
Vibrations on exhaust valve of unit no 8 are observed at 336°, much sooner than the other on the other units. As a conclusion of this analysis it was recommended to check the exhaust valve clearance.
3 SHIP ENGINEERS CHECKS
The engine was cooled down then the cylinder head no 8 cap was disassembled to access the rocker arm device. The clearance was measured by a feeler gauge and the clearance was found to be substantial. On a cold engine exhaust valve clearance should be 0,5 [mm]. The exhaust valve clearance was adjusted.
4 REMEASURE
After the adjustment was made the engine was started and new measurements were taken the results can be shown as follow:
It is clearly shown that all the valves are closing at the same moment.
5 CONCLUSIONS
It can be concluded that the diagnosis obtained from the measurements and the data analysis was correct