DOUBLE/TRIPLE-LAYER VALVE GUIDE

摘要

The invention relates to a valve guide for internal combustion engines which is manufactured by powder metallurgical processes and comprises a central section, an end piece facing the cam, and an end piece facing the duct. The central section is made of a first material and the end piece facing the duct is made of a second material which has a hardness of more than 70 HRB, while the first material has a hardness that is at least 10 HRB lower that that of the second material.