Faults of camshaft
- worn or damaged camshaft pulley;
- wear of a camshaft drive belt;
- damage or wear of the camshaft cams;
- bearing wear;
- deformation of the cavity and the surface of the shaft;
- wear of keyseats;
- deterioration of journals;
- wear of thread.
Symptoms of a camshaft fault
- malfunction of the engine in all modes;
- violation of timing;
- a significant decline in engine power;
- abnormal noise on the camshaft drive;
- shooting sound in the silencer;
- dips in the cycles of the cold engine;
- indications of fault on the instrument panel.
Causes of faulty camshaft
- use of low-quality lubricants and fuels;
- insufficient oil level in the system;
- insufficient pressure in the lubricating system;
- getting fuel into the lubricant;
- frequent engine overheating;
- excessive engine mileage;
- damage to the drive parts;
- the timing adjustment is not correct;
- abnormal clearances in the valve mechanism.
Diagnostics
Defects of the camshaft can be detected only at the stand with special equipment. The shaft is removed, and the thickness and the wear level of the cams is determined as well as the presence of deflections, deformations, cracks and other defects. Dismantling of the shaft is also carried out only at a service station. Independently, you can check related systems: lubrication, power, and the engine cooling that will provide indirect information on the camshaft state. The system diagnosis is recommended every 75 000-100 000 kilometers.
Repair of camshaft
It is worth noting that only the cams galling is subject to repair. It is corrected by electro-deposition of chromium. In this process the part cavities are filled with asbestos for protection. Chromium coating of the partis made to reduce wear and extend the life of its components. With that the allowed thickness of the journals’ backlash deflection is only 0.03 mm. The metal hardness may be in the range of HRC 26-60.
Replacing the camshaft
In the presence of camshaft cracks, excessive journals’ deflection, destruction or keyseats or seats only replacement is required. You can do it on your own, but it is better to entrust it to professionals. At the same time it is necessary to make the analysis of seals and the camshaft holder plate.
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