The common breakdown of camshafft including:abnormal wear,abnormal sound and breakage,before happen the abnormal sound and breakage will happen the symptom of abnormal wear.
(1)Almost all camshaft located in the end of engine lubricating system,therefore the lubricating condition is not very optimistic.If due to the long time use of fuel pump cause the lack of oil supply pressure,or the oil channel breakage cause the lubricating oil can not reach the camshaft,or the tightening torque of tight bolt of bearing cover is too bigthen cause the lubricating oil can not go inside the space between camshaft,all those will casuse the abnormal wear of camshaft.
(2)The abnormal wear of camshaft will cause the space extend between camshaft and bearing ,when the camshaft moving will happen axial displacement,thus happen abnormal sound.The abnormal wear also will cause the space extend of drive cam and oil tappet,when the cam and oil tappet connect ,will happen the strike and then appear abnormal sound.
(3)The camshaft sometimes will happen some serious breakdown like breakage ,the common reasons are:the crack or serious wear of oil tappet,serious lack of lubricating,bad quality of camsaft and the breakage of timing gear.
(4)Under some condition ,the breakdown of camshaft is human causes,especially when fix the engine ,did't apply the correct assembly and disassembly.For exemple ,when disassembly the bearing cover of camshaft,use hammer hit strongly or use screwdriver pry and press ,or when install the bearing cover put the position wrongly and cause the mismatching of beraing cover and bearing,or fastening bolt of bearing cover have too big tightening torque etc.When install the bearing cover ,be careful about the arrows and position put over surface of bearing cover ,and follow strictly specified moment of force to use the torque wrench to tight the fastening bolt of bearing cover.