Valve Guides

Pral Exports offers valve guides. In most types of piston engines, a valve guide is provided for each engine valve in the cylinder head. Along with the valve spring, it serves to positively locate the valve so that it may make proper contact with the valve seat. A valve guide is a tube-shaped piece of metal, pressed into the cylinder head, with the valve reciprocating inside it. Guides serve also to conduct heat from the combustion process out from the exhaust valve and into the cylinder head where it may be taken up by the cooling system. Usually valve guides are made up of different materials as per their requirements in specific applications. Cast iron is used for small engines. Tin bronze, aluminium bronze and other alloys such as manganese bronze and leaded phosphor bronze are used to manufacture valve guides. These materials provide good thermal conductivity. Crystallisation process makes guides wear resistant.