The first one is that the fuel quality is substandard

There is a chemical component in gasoline called olefin, which is prone to oxidation to form a gel-like substance. Gasoline with excessive olefin content is very likely to form carbon deposits on the intake valves and combustion chambers. Its greater harm is that after combustion, it is prone to form an asphalt-like gel-like substance, presenting a black and shiny appearance, mainly accumulating in the valve head, valve stem, and valve guide sections.

When the engine is running at high temperatures, it is soft. However, as the engine cools down after stopping, this gel-like substance will solidify. When it is started again, at best, the valves will be bent; at worst, both the pistons and valves will be damaged. The joystick machine may experience situations such as the joystick bending or falling, while the chain machine may have its upper rocker arm broken.

The second issue is that the fit clearance between the valve and the valve guide is not standard

If it is too small, at high temperatures, due to the different expansion coefficients of the valve and the guide pipe, the resistance the valve encounters when moving in the guide pipe will be too large, causing the valve to break. When the fit clearance between the valve and the guide is too large, it can also cause the valve to break at high speed.

The third is the quality issue of the conduit and the valve

Their uneven expansion at high temperatures can cause the valves to get stuck at high speeds and also lead to valve breakage.

The fourth point is that the elasticity of the valve spring weakens

At high speed, the valve cannot be reset well in an instant, resulting in a valve breakage accident.

The fifth is the detachment of the air lock clip

When the spring force of the valve is too large, the impact force generated between the valve head and the lock clip during the valve's return to position is too great, which will cause premature wear of the valve head and the lock clip, leading to the detachment of the valve lock clip. This may also be due to the quality of the valve itself.

The sixth reason is that the quality of the lubricating oil is too poor or the oil supply to the cylinder head is too small

The quality of the lubricating oil is too poor. At high temperatures, it fails to play the due role of lubrication and reducing friction. Coupled with a small amount of carbon deposits and sludge, the valves cannot return to their original position well, causing a series of mechanical accidents.

The seventh is excessive carbon deposits on the pistons and valves

A mechanical accident that causes the valve to break.

The eighth point is that some car owners like to slam on the accelerator when the car is cold

This leads to insufficient lubricating oil cooling for the exhaust valve and the guide pipe, causing a sharp increase in temperature. As a result, the valve cannot move normally within the guide pipe, causing the piston to strike the valve and resulting in a serious mechanical accident.

The ninth is the misalignment of the timing of qi matching

It leads to the consequence of the valve hitting the piston, causing the valve to break and the piston to be scrapped.

The tenth is that the valve clearance is too large

This results in the CAM and rocker arm being unable to precisely control the opening and closing of the valve at high speeds, leading to serious mechanical accidents.

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