Taking into account temperature, impact, sliding and environment, the authors have developed an impact wear testing machine equipped with a furnace and sliding mechanism in order to simulate valve and valve seat insert wear in actual 0043.1648/95/$09.50 0 1995 Elsevier Science S.A. All rights reserved SSDfOO43-1648(95)06656-X engines. A previous report [3] presented the results of an investigation concerning the effects of temperature and sliding speed on the impact wear characteristics of a JIS SUH3 steel valve material and a sintered alloy valve seat insert material at high temperature. In this work, an investigation was made of the effects of temperature and sliding speed on the impact wear characteristics of a JIS SUH36 steel valve material and a sintered alloy valve seat insert material at high temperature.