The cylindrical hole which is located in the cylinder head or block through which the stem of the poppet valve passes. It is designed to keep the valve in proper alignment. It also serves as a bearing surface. Some guides are pressed into place and others are merely drilled in the block or in the head metal.
VALVE GUIDE
Meaning of VALVE GUIDE in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012