How to adjust the valve of in-line four-cylinder engine

There is no order, everything needs to be measured!

Keep the valve closed (piston top dead center) and measure the valve clearance of each cylinder! Just use a feeler gauge.

Function is to adjust the valve clearance within a reasonable range:

The clearance of the intake valve is between 0.2 and 0.25mm.

The exhaust valve is generally between 0.29 and 0.35.

Excessive clearance: After the intake valve and exhaust valve are opened late, the intake and exhaust time is shortened, and the valve opening height is reduced, which changes the normal valve timing and makes the engine power drop due to insufficient intake and unclean exhaust. In addition, the impact of valve train parts increases and the wear accelerates.

Too small clearance: after the engine works, the parts are heated and expanded, pushing open the valve, which makes the valve not close tightly, causing air leakage, reducing power, causing serious carbon deposition or burns on the sealing surface of the valve, and even the valve hits the piston.

The hydraulic tappet valve train has the function of automatically adjusting the clearance, and there is no need to leave the valve clearance.