What consequences to be expected if piston lacks of lubrication?
25 Sep '19, 08:56
Based on real-life experience, the consequences of seized piston lubrication are severe:
Firstly, piston rings will stick completely in their grooves due to lack of lubrication. At the same time, the piston starts tearing the liner directly, being damaged and damaging the liner.
The liner will be severely damaged by a piston which reciprocated without lubrication. Due to combustion and tear, liner wil be overheated. This leads to discoloration and excessive thermal shock. Finally, the liner may crack, as it happened on one of my vessels. Pay attention to the crack at the lower part of liner.
LO contamination by water
If the engine is allowed to run with a cracked liner, the water will get into the crankcase and contaminate the LO.
When contaminated with water, LO to loses its lubricity properties. Presence of water in oil damages the lubrication film and disrupts the boundary lubrication. This lead to main and crankpin bearings damage.
In our case with Yanmar engine, the root cause of the breakdown was a damaged piston nozzle, which supplies lube oil to the piston for cooling and lubrication.
25 Sep '19, 12:49