The valve guide is the guide device for the valve. The valve guide is used to guide the valve and transfer the heat from the valve rod to the cylinder head through the valve guide.The operating temperature of the valve guide is also high, about 200℃. When the valve rod moves in the guide, it is lubricated only by the oil spilled from the valve mechanism, so it is easy to wear. Therefore, the valve guide are mostly made of ductile iron or powder metallurgy materials with self-lubricating properties. And they are pressed into the valve guide seat hole of the cylinder head with a certain interference, to prevent falling off.
