What are the common faults of automobile camshafts?

Common faults of automobile camshafts mainly include wear, deformation, fracture, sensor failure and phase failure, etc. The following is a detailed introduction:

Camshaft wear
Cam wear: This is one of the most common faults of the camshaft. Due to frequent friction and contact stress between the cam and components such as valve tappets or rocker arms, the cam surface will wear after long-term use. Wear will cause the profile of the cam to change, making the lift and opening time of the valve inaccurate, which will affect the intake and exhaust effects of the engine, resulting in reduced engine power, increased fuel consumption, and difficulty in starting.
Journal wear: The camshaft journal and bearing mating are also prone to wear. Journal wear will increase the matching clearance, causing the camshaft to loosen and shake during operation, generating abnormal noise, and also affecting the rotation flexibility and stability of the camshaft. In severe cases, it may cause the engine oil pressure to drop, affecting the normal lubrication of the engine.

Camshaft deformation
Manufacturing defects or improper installation: During the manufacturing process of the camshaft, if there are problems such as uneven materials and improper heat treatment process, the camshaft may be deformed during use. In addition, when installing the camshaft, if the installation torque is uneven or the installation position is incorrect, the camshaft will also be subjected to additional stress, causing deformation.
Engine overheating: When the engine overheats due to cooling system failure, long-term high-load operation, etc., the camshaft will deform due to uneven thermal expansion. Camshaft deformation will cause deviations in valve opening and closing time and lift, affecting the normal operation of the engine, causing engine jitter, power reduction, and excessive emissions.

Camshaft fracture
Material defects: If the camshaft material has defects such as inclusions and pores, or the material strength and toughness are insufficient, the camshaft may not be able to withstand huge stress and break when the engine runs at high speed and high load.
Fatigue fracture: Under long-term and repeated alternating loads, fatigue cracks will occur in the camshaft, and as the cracks continue to expand, the camshaft will eventually break. Fatigue fracture usually occurs at the stress concentration points of the camshaft, such as the transition between the cam and the journal, keyway, etc.

Camshaft sensor failure
Sensor damage: The camshaft position sensor is an important component in the engine electronic control system, which is used to monitor the position and speed of the camshaft and transmit the signal to the engine control unit (ECU). The sensor may be damaged due to aging, short circuit, open circuit and other reasons of the internal electronic components, resulting in the ECU unable to accurately obtain the position information of the camshaft, which will cause the engine ignition and injection timing to be disordered, and the engine will have problems such as difficulty in starting, unstable idle speed, and poor acceleration.
Signal interference: If the sensor line is subject to electromagnetic interference, or the sensor is improperly installed, resulting in inaccurate signal transmission, the engine control system will also fail.

Camshaft phase failure
Variable camshaft phase system failure: In some advanced engines, variable camshaft phase technology is used to optimize the engine performance under different working conditions by adjusting the phase of the camshaft. However, the solenoid valve, oil pressure control mechanism and other components in the variable camshaft phase system may fail, resulting in the camshaft phase cannot be accurately adjusted or adjusted in time. This will prevent the engine from obtaining the best intake and exhaust effects under certain working conditions, affecting the engine's power output and fuel economy.
Timing chain or belt failure: The timing chain or belt is used to connect the crankshaft and camshaft to ensure the correct transmission ratio and phase relationship between the two. If the timing chain or belt is loose, jumps teeth, or is stretched, the phase between the camshaft and the crankshaft will deviate, making the engine's valve opening and closing time inconsistent with the piston movement, causing engine jitter, power loss, or even failure to start.