1. Cracking & Fracture of Crankshaft
To check the cracking of crankshaft: by oil-soaked knocking, that is to immerse the crankshaft in the kerosene for a while
and then take out and wipe it dry. Spread some white powder onto the crankshaft and hammer its non-working face. After
vibrating, if oil stain appears, it proves the existence of cracking. Magnetic inspection: magnetize the parts through
magnetic inspector. If the parts are cracked, the magnetic pole will appear in cracked area. If you spray some pulverized
irons on the parts, the iron powder would be absorbed on the cracked area. So that the crack becomes easily visible. But
after the magnetic inspection, it is necessary to demagnetize it.
Once the crankshaft is cracked, have it replaced. If bending deformation appears in the crankshaft, apply a cold press
rectification or cylinder block rectification to repair it.
II. Wear of Flywheel Working Face and Damages to Gear Ring
1. Normally, when starting the engine, the flywheel gear ring and starter pinion easily collide with each other or have poor
engagement between the two teeth, thus easily leading to wear and damages to the teeth.
a. When the teeth of gear ring are worn on one side, turn it over for further use. The gear ring detaching or assemble needs
heating. After it is repaired and assembled, it is necessary to provide interference for the flywheel gear ring.
b. If any single tooth is damaged, use oil stone to repair and grind it. If serious wear or teeth damages take place on both
sides of gearing ring, it is possible to repaire by stack welding.
2. If the working face of flywheel wears or is grooved with depth over 0.5mm, it is proper to apply polishing or polishing after
finish-machining. If the wave depth is not over 0.5mm, it is allowed to have two ring grooves. After machining, the thickness
of gear should not be less than new flywheel teeth for over 2mm.
Section 3 Disassembly & Maintenance of
Crank Mechanism
83
Содержание JL481Q
Страница 1: ......
Страница 9: ...5 Fig 3 Components Assembly Drawing of MR479Q MR479QA Engine ...
Страница 10: ...6 Fig 4 MR479Q MR479QA Engine and Its Power System ...
Страница 11: ...7 Fig 5 Assembly Drawing of Engine and Its Auxiliaries MR479Q MR479QA ...
Страница 12: ...8 Fig 6 Electronic Control Fuel Injection System in Engine MR479Q MR479QA ...
Страница 13: ...9 Fig 7 Front view of Engine JL481Q MR481QA ...
Страница 14: ...10 Fig 8 Sectional elevation of Engine JL481Q MR481QA ...
Страница 15: ...11 Fig 9 Electronic Control Fuel Injection System in Engine JL481Q MR481QA ...
Страница 21: ...17 Fig 13 Exterior Feature of JL481Q Engine Power Me N m Torque Pe Kw ge g kwh Fuel Consumption Ratio ...