What is the function of the engine valve guide?

[LaAthena]

The engine valve guide serves to guide the movement of the valve, ensuring that the valve performs reciprocating linear motion, allowing the valve to correctly fit with the valve seat ring, and transferring the heat from the valve stem to the cylinder head. The valve guide operates at relatively high temperatures with poor lubrication, typically made of cast iron with high graphite content or iron-based powder metallurgy to enhance self-lubricating properties. Installation method of the valve guide: The inner and outer cylindrical surfaces of the valve guide are processed and then pressed into the valve guide hole of the cylinder head or cylinder block, followed by fine machining to ream the inner hole. To prevent axial rotation, a retaining ring positioning groove is provided, and when paired with the positioning retaining ring, it prevents the guide from moving during operation and falling into the cylinder. A slight gap is generally left between the valve stem and the valve guide to allow the valve stem to move freely within the guide.