Many people may not familiar with camshafts, but today let’s talk about their common faults and modifications of them.

Common faults of the camshaft

Common faults of camshaft include abnormal wear, abnormal noise, and fracture. Abnormal wear often occurs before abnormal noise and fracture.

• The camshaft is almost at the end of the engine lubrication system, so the lubrication condition is not optimistic. If the oil pump has insufficient oil supply pressure due to too long service time, or the lubricating oil duct is blocked, which makes the lubricating oil unable to reach the camshaft, or the tightening torque of the fastening bolts of the bearing cover is too large, which makes the lubricating oil unable to enter the camshaft clearance, it will cause abnormal wear of the camshaft.

• The abnormal wear of the camshaft will lead to the increase of the clearance between the camshaft and the bearing seat, and the axial displacement will occur when the camshaft moves, thus producing abnormal noise. Abnormal wear will also lead to an increase in the clearance between the driving cam and the hydraulic tappet. When the cam is combined with the hydraulic tappet, there will be a collision, resulting in abnormal noise.

• The camshaft sometimes breaks and other serious faults occur. The common causes are hydraulic tappets broken or severely worn, severe poor lubrication, poor camshaft quality, and camshaft timing gear breakage.

• In some cases, the camshaft failure is caused by human factors, especially when the camshaft is not disassembled correctly during engine maintenance. For example, when disassembling the camshaft bearing cover, use a hammer to forcefully knock or use a screwdriver to pry, or install the bearing cover in the wrong position, resulting in the mismatch between the bearing cover and the bearing seat, or the tightening torque of the fastening bolts of the bearing cover is too large. When installing the bearing cover, pay attention to the direction arrow, position number, and other marks on the surface of the bearing cover, and tighten the fastening bolts of the bearing cover with a torque wrench in strict accordance with the specified torque.

Modification of camshaft

To improve the power of the engine, some modification shops have modified the camshaft of the engine, among which replacing the high angle camshaft (Hi CAM) is a common modification method. This modification operation is not complicated, but because some modification personnel do not know enough about the working angle and working principle of the cam on the camshaft, the effect after modification is not obvious and even leads to the deterioration of the engine performance.

The high angle camshaft is relative to the cam working angle of about 240 ° of the ordinary camshaft, and the cam working angle of the high angle camshaft can usually reach more than 280 °. The camshaft with a large angle can extend the opening time of the valve, increase the lift of the valve, enable the inlet valve and exhaust valve to open early and close late, enable more air to enter the cylinder and improve the power output of the engine at medium and high speeds. For civil vehicles, camshafts with a cam working angle of less than 278 ° should be selected when refitting, because camshafts with a working angle of more than 278 ° will greatly increase the valve overlap angle, which will greatly increase the power of the engine at high engine speeds. However, at low engine speeds, due to poor cylinder sealing, the idle speed will shake severely and even stall, which makes such vehicles unable to adapt to daily use, It can only be used for competition.

Searching for china camshaft suppliers, welcome to contact us.