Our engineers performed a free engine survey for a marine operator recently – there had been reports of fuel reaching the sump oil and diluting it.
During our investigations, we found a continued increase of fuel oil contained within the oil sump pan, along with the presence of vibration, blue smoke and reduced power.
We borescoped the unit and found that cylinder number 12 had a partially missing valve.
The consequence? As the unit’s injection is common rail, any fuel being entered into the cylinder was not igniting but instead being pumped into the sump, while there was also an indication of water ingression in both cylinder banks.
Due to the engine’s running hours, our engineers recommended that the engine should be sent to our workshop for a full overhaul.
As it happens, this operator had already asked us to source another engine which had just arrived in the workshop.
We got to work, adapting it as a direct replacement for this engine (the filters etc needed to be moved to the opposite bank) and it is now ready to go back to the operator for installation with minimal downtime.
The original engine overhaul will continue and they will have it on hand as a swingset engine, ready to be installed when needed, again minimising cost and downtime.
As an insight, during the inspection of the original engine in our workshop, the following damage was found:
- The 2 turbochargers were removed and had damage to both turbine wheel assemblies; this could reduce the engine boost pressure and power
- Corrosion and water contamination were found within the charger air cooler air box structure
- The fuel oil cooler rubber hose connection had been damaged in the past
- The Inlet valve on cylinder right 12 had a section missing and the piston crown was filled with fuel
- Piston crown on cylinder R12, with damage from broken valve being bounced around and pieces entering into cylinder R8
- The cylinder liner has the appearance of an attempt to hone, with what appears to be very coarse emery cloth used in one direction
- Scoring – which can be felt with a fingernail – was found around one of the journals on the left bank camshafts