Applied

Engine Repairs

Distorted gaskets where installed which  did not sit tightly on the Liner Profile. When the head was placed on the liner the Gasket was able to move so it no longer sat in the correct position.


Head tightening was sufficient to further distort the soft copper so that part became exposed to the combustion chamber


Copper detached either through mechanical damage or through melting, further melted during to combustion temperatures and was able to pass between liner and  piston as the initiator for further damage.


Additionally, or possibly alternately the upper area of the liner may have been distorted by the extrusion of the copper causing rub on the piston


Prompt action   by  attending engineers prevent what would have been heavily overloaded Main bearings from wiping leading most likely to loss of Crankshaft..


Although there was sufficient spares to resolve this matter, the ability to resolve similar in future is becoming limited as excess stock supplied to the vessel is used..  


Synopsis

Following 16000 Hour service No5 Engine was started locally.  Immediately significant noise and smoke was generated and the engine was quickly stopped.


On disassembly the Piston was found to be seized in the liner requiring both parts to be removed together.


New Piston and liner assembly installed, engine Run satisfactory


Inspection

The Piston was seized in the Liner and during period of attendance to the vessel was not removed. Head in good condition.


Head gasket displaced leading to  gross distortion being compressed by the profiled of the Liner top and extruded on the opposite side up the spigot of the Head.Evidence of limited Gas passing across gasket.


Main bearing appears in good condition with no apparent signs of Overloading or lubrication film breakdown.


A Number of the Spare gaskets for immediate use seen to be distorted to non flat shape. Measurement of gaskets  indicated and out of roundness iro 1mm of those measured

Arrangement


Pictures

Showing extruded gasket up spigot


Close up of above

Showing opposite side

Showing distorted gaskets


Showing Galled Piston in Liner


Big End Bearing