(1) Ensure that the valve head has sufficient rigidity during the repair. When the contact portion between the intake valve head and the valve seat is upward, or the thickness of the valve head is reduced to less than 0.8 mm, the valve head will be elastically deformed due to the impact of the gas pressure in the cylinder, and the valve head will be reduced after the load is reduced. It restored its original shape again. Therefore, the valve is working in continuous elastic deformation. The contact cone surface is subjected to high-pressure sliding dry friction, resulting in metal wear, which is easy to grind the intake valve cone surface into an arc shape, which affects the performance of the diesel engine. Therefore, when grinding the working surface of the valve head, the smaller the grinding amount, the better, so as to ensure the thickness of the valve head and make it have sufficient rigidity. When repairing, it is found that the thickness of the valve head is less than 0.8 mm, and the valve rod wear exceeds 0.125 mm, it should be replaced with a new one. Our company provides a commercial vehicle engine valve.
(2) Check the spring force of the valve spring. After the spring force of the valve spring is weakened, if it is not checked and not replaced during repair, the seating pressure of the valve will be reduced, the lattice deformation of the metal surface layer of the valve seat working surface will be small, the deformation stress will be low, and the hardened layer will be difficult to form Sexuality is reduced accordingly, and it is easy to make the valve leak. Therefore, when repairing a diesel engine that has been used for many years, the spring force of the valve spring must be checked to ensure the spring force of the valve spring, thereby maintaining the valve seating pressure.
(3) Ensure that the contact ring between the valve and the seat is within the specified range. Most of the heat of the valve is conducted out through the sealing tape, the heat transfer effect of the sealing bandwidth is good, and the operating temperature of the valve is lower, but it is easy to reduce the sealing performance due to the formation of erosion spots on the gasket. Too narrow, although the sealing is good, the heat dissipation is poor, it is easy to accelerate the valve wear and make the valve working surface groove. Therefore, when repairing, the contact ring should be controlled within the range of 1.5 to 2.5 mm.
The above information is provided by the engine Intake Exhaust valve manufacturer.