DIESEL MAIN ENGINE / MAIN BEARING CONCERN
This document consists of the detection of an issue in the area of main bearing no 5 and 6 of a Bergen C25:33L9PY Main Engine PS of Zamil 55 ship. A Hi, Raw, Ultra vibration and PV measurements were performed with vibration equipment, the results were analyzed.
The main bearing condition is based on the strong Hi Freq Vib signal readings taken during the engine operation. The data obtained from the engine analysis was processed, analyzed and compiled by a qualified professional analyst, resulting in the following recommendation:
- Crankshaft deflection measurement needs to be done as soon as possible.
2.1 THEORETICAL REFRENCES:
Strong Hi Freq Vib signal indicates a problem of excess clearance on the main bearings.
2.2 VIBRATIONS SHOWN
Vibration measurements acquired can be shown as follow:
Main bearing no 5 and 6 Hi Freq Vib signals are much stronger than on the other main bearings. As a conclusion of this analysis it was recommended to perform the crankshaft deflection measurement.
3 SHIP ENGINEERS CHECKS
The engine has been shut down and left to cool down. Then the crankshaft covers where dismantled to access the crankshaft. The deflection measurement was found to be over the limit. For this type of engine crankshaft measurement readings should be between 0,02[mm] and 0,10 [mm]. Crew decided that the main bearings will be changed on next drydock due to lack of spare main bearings on board.
It can be concluded that the diagnosis obtained from the measurements and the data analysis was correct. The crew was informed to reduce the load on the engine to 50%. New vibration measurement will be performed after the main bearings no 5 and 6 are replaced.