1. What usually happens with valve springs
Under the long-term action of high temperature and periodic high-frequency alternating force, the valve spring is prone to wear and deformation after a period of use. In that case, the elastic force of the spring will be weakened or reduced, causing the valve to close tightly. The engine power of the machine is reduced, and the setting is difficult to start. If the vehicle stops at an intersection and does not move, do you think about the traffic situation at that time?
When the spring force of the delivery valve spring is weakened. This will cause the internal leakage of the high-pressure oil to become serious, the remaining pressure in the high-pressure oil pipe will decrease, the oil outlet valve will not be seated quickly, and the fuel supply will be reduced and unstable, the engine will be weak or “traveling”. In addition, the fuel injector will be weak at the beginning, the fuel will not be cut off simply, and the phenomenon of back drip will occur. As a result, the engine overheats, the combustion deteriorates, and the exhaust emits black smoke, which causes certain environmental pollution.
2. Measures to cope with changes in valve springs
In normal times, remember to check regularly whether the elasticity of the valve spring is good. You can do a test to detect the degree of shortening. A practical little trick is to put a small piece of iron between the old spring and the new spring and clamp it on a bench vise for comparison. It can be seen.
When the new spring is compressed to 2/3 of the original length, if the new spring is 2mm longer than the old spring, it should be replaced.
We should note that, under normal circumstances, the valve spring should be replaced after 2500-3000 hours of use. If there is any bending or deformation, it should be replaced in time.