Common failure of the camshaft include abnormal fracture, wear, sound and sound before and fracture occurs often appear the symptom of abnormal wear. The camshaft
(1) the camshaft almost, at the end of the engine lubrication system, so the lubrication condition is not optimistic. If the oil pump, oil pressure appear because time is too long wait for a reason, or oil duct blockage caused by lubricant cannot reach the camshaft, or bearing cap fastening bolt tightening torque is too large to lubricating oil into the camshaft clearance, will cause abnormal wear of camshaft.
(2) the camshaft of abnormal wear can cause between the CAM shaft and bearing clearance increases, the camshaft happens when axial displacement, so as to produce the sound. Abnormal wear and tear can also lead to drive between the CAM and the hydraulic tappet clearance increases, CAM combined with hydraulic tappet collision happens, to produce sound.
(3) the camshaft sometimes appear the serious problems such as fracture, common cause with hydraulic tappet rupture or serious wear and poor lubrication, poor quality of the camshaft and camshaft timing gear fracture.
(4) in some cases, the failure of the camshaft is human causes, especially when repairing the engine camshaft for disassembling without properly. Strength such as removing the camshaft bearing cover with a hammer percussion or with a screwdriver to pry pressure, or install the bearing cap to the wrong location cause bearing cover and bearing seat do not match, or bearing cap fastening bolt tightening torque is too big, etc. When install the bearing cover, should pay attention to the direction of the arrow on the surface of the bearing cover and position number tags, and in strict accordance with the provisions of the bolt torque using a torque wrench to tighten the bearing cover.