Bearing wear pattern assessment: what does it tell you?
Dismounted bearings during an engine overhaul can tell you very interes
ting stories about your crankshaft and alignment condition. Always ask for an assessment of the bottom shells of the main bearings, as they give you a lot of information about your engine alignment, deflection readings and edge loading.
By doing so, you will note the HOT deflection readings will correspond with the running pattern you see (crank webs inwards or outwards), and horizontal misallignment will clearly show (i.e. seafastenings too tight in running conditions).
High vertical load on output shafts (misaligned gearbox) will show as edge loading on last and forelast bearings.
Big end bearings top shells may not tell you as much about the alignment, but they tell you all about the condition of the crankpin surface. The presence of wear ridges need an expert eye to measure on the shaft, but they can easily be translated from the running pattern.
Installing new bearing shells in the conditions mentioned above can cause major damage to your engine; if you need any assistance in the bearing assessment, just give us a call!
