What if the valve clearance is too small?

The greater the valve clearance, the lower the combustion chamber pressure, that is, the worse the power, the greater the engine noise. The valve clearance of the new car just bought has not been completely matched. The best way is to start the car in place, open the hood and let it run at idle speed for five or six hours, so that the valve clearance can be well adjusted under no load. If you are sensitive to the engine sound, you will find that the engine sound will be much quieter and the sound of refueling will be much cooler after idling for five or six hours.