Appendix
39
Cam height Exhaust
4.723mm
4.35mm
Inspect the outer diameter of the camshaft journal.
When it is less than the service limit, the camshaft should
be replaced.
Standard
Maintenance limit
16mm
15.916mm
Analysis on causes of camshaft wear and its impact on the performance of whole gasoline engine:
The main cause for abnormal camshaft wear of the camshaft is poor lubrication, Factors such as low
oil viscosity, many impurities and small circulating oil volume is unable to form complete oil film on the
camshaft surface, to cause it to be in a state of high-speed dry friction, resulting in serious wear on the cam
surface. The second is assembly accuracy of the camshaft. When matching clearance between camshaft
journal and camshaft seat or bearing is out of tolerance, rotation accuracy of the camshaft will decrease,
and the contact with related parts will generate deviation plane t cause abnormal wear.
⑤
Timing gear
Inspect meshing clearance of the timing gear, which shall align marks of gears on both sides.
The main damage of timing gear is the wear of gear tooth, tooth face peeling or roughness, gear deflection,
gear tooth breakage, etc.Due to the wear of gear teeth, the greater the meshing clearance is, the greater the
noise will be.
If gear face of timing tooth is bruised or damaged or rupture angle, it shall be replaced with a new one for
any case.
When replacing new parts, it is better to replace the whole part to ensure that there is a
more consistent meshing surface.
3-4-7 Starting control box
a. Disassembly and assembly
(Automatic starter specification only)
Camshaft gear
Crankshaft gear
Alignment mark
