WARTSILA RT-FLEX CAMSHAFT REPLACEMENT
HEAVY DAMAGE ON NO:1 PUMP ROLLER
As requested our service team has attended to vessel to replace M/E fuel supply unit camshaft and NO:1 fuel supply
pump while vessel anchored.
Observed heavy damage on roller of M/E NO:1 fuel supply pump and NO:1 cam of supply unit camshaft.
Camshaft, camshaft bearings and NO:1 fuel supply pump has replaced with owner supplied spare parts, proper
lubrication of bearings, pump roller and gears confirmed, all relavant measurements taken and system boxed up.
You can find relevant pictures and measurements as below.
CAMSHAFT BEARING RADIAL CLEARENCES
| NO:1 | NO:2 | NO:3 | NO:4 | NO:5 | |
|---|---|---|---|---|---|
| Clearance | See remark* | See remark* | 0.12 mm | 0.12 mm | 0.12 mm |
REMARK*: It is not feasible to measure NO:1 and NO:2 bearing clearances with feeler gauge, however we have
confirmed proper clearance by dial gauge.
CAMSHAFT AXIAL CLEARENCE :0.36 mm
NO:1 FUEL PUMP ROLLER CLEARANCE :0.08 mm
As per our observation and best knowledge root cause of damage is seized roller.
As you can see below Wartsila training document, main reason of seized roller due to:
- Lub oil contamination
- Lub oil supply pressure
- Clearence of the pump housing
- Lub oil contamination.
- Lub oil supply pressure.
- Clearance of the pump housing.
Roller Seized:
The following should be checked:Considering while no damage observed in NO:2 supply pump so far but NO:1 supply pump damaged twice, it can be considered problem is not related with lubrication oil condition (supported with good lub oil analyse).
Lubrication oil to both pump supplying from same line, and we have confirmed lubrication flow to both pumps, however not possible to measure oil pressure for lubrication of roller.
We did not observe any sign of fuel leakage to roller which is one of the reasons of roller damages, so it can be ignored.
As per maker’s design lubrication oil reaching the pump through pump housing and it is very important to proper clearance between pump housing and pump body to obtain proper lub oil pressure, so it can be considered measure the clearance and ovality for both pump housing and compare.
RECOMMENDATION:
- Inspect both pump’s rollers at every port for any abnormality. Recommend purchase genuine pump cut of tool (94430)(which is missing on board) and cut off the NO:1 pump during inspection and turn the roller by hand, if observe any resistance replace the roller. Great care to be taken to prevent injury of hand during the inspection
- You can shift the oil mist sensor to NO:1 pump side, so it can warn earlier if similar problem occurs.
- During the operation measure the temperature by laser gun to compare temperature between both pump rollers.
- You can consider installing PT100 temperature sensor below both rollers drain to monitor temperature regularly.
- 5. There is a connection where a lub oil pressure gauge can be installed to see oil supply pressure to rollers, recommend connect a pressure gauge to same point and see no pressure drop or fluctuation during the operation.
