2.1 Visual inspection
The fractured camshaft is shown in Fig.1. From Fig.1, it is
found that the fracture had taken place in the journal region
between exhaust cam and admission cam of the 2nd cylinder
in the engine. Adherent fins at the molding parting of the
fractured camshaft was not thoroughly trimmed, yet, as shown
in Fig.2. In addition, there was obvious extruded trace on the
interior wall surface of camshaft hole of cylinder head. White
macroscopical section of the fracture zone shown in Fig.3 is
signifi cantly different from the camshaft from France shown in
Fig.4.