Valve Seat Inserts (VSIs) have to satisfy extreme requirements such as high temperature resistance, low wear rates, impact behavior and excellent heat conductivity in car engines. The high copper content in alloy composition significantly improves the thermal properties of the component and machinability of the materials. We use a technique known as infiltration to fill porous spaces with copper and achieve high densities in VSIs. However, some parameters like infiltrant composition, base compact density and sintering condition affect the final properties. This paper presents the most important requirements that should be considered in infiltration process. For this purpose different infiltrant composition and base compact densities were selected. The sintering was carried out in two conventional mesh belt and walking beam sintering furnaces under endothermic and dissociated ammonia atmosphere, respectively. The results of these studies are presented using sintered density, hardness and radial crush strength properties. Also, microstructure analysis was used to interpret the resultant properties.