What is the clearance of the car valve?

The best position for adjusting valve clearance is about 0.20mm ~ 0.25mm for intake valve and 0.25mm ~ 0.30mm for exhaust valve. But the exact size depends on the model. Generally, the valve clearance of diesel vehicles is a little larger than that of gasoline vehicles. The clearance between the intake and exhaust valves of an automobile is generally between 0. 15-0.40mm, and the specific data can be found in the on-board manual. My car manual says that the clearance of intake valve is 0. 15-0.25, and that of exhaust valve is 0.25-0.35. The working principle of automobile valve clearance is: 1. When the engine is working, the valve expands with the increase of temperature; 2. If there is no gap between the valve and its actuator in the cold state or the gap is too small, the thermal expansion of the valve and its actuator will lead to the valve not being closed strictly in the hot state, and the engine will leak during the compression stroke, which will seriously affect the life of the engine. In order to eliminate this phenomenon, in general, when the engine is cold assembled, a certain gap is left between the valve and its transmission mechanism to compensate for the expansion of the valve after heating. This clearance is called valve clearance.