EXHAUST VALVE LOCKING GETTING LOOSENED AND DAMAGING THE ENGINE :
JOSE RAJ RAVI, 2/E
The main engine was a V shaped 14 unit engine. On starting the engine, a knocking noise was heard from one side of the engine and engine seized. On inspection it was found that in one of the units, the exhaust valve locking got loose and the valve fell on top of the piston causing a big hole on top of the piston. The cylinder head of damaged unit was opened up and the broken valve pieces were taken out. When tried to take out the piston, piston was not coming out as it got seized inside the liner. Then by using ice on top of the piston and using jacks, piston with connecting rod could be taken out.
The liner also found damaged badly and the liner was also taken out. Both liner and piston renewed from spares. Overhauled exhaust valve was lapped on to the cylinder head seat and exhaust valve fitted and locked properly. The engine was tried out and started, satisfactory.
Lesson learnt :
it is better to check the valve locking mechanism, when routines are being carried out to avoid such damages and mishaps.