This paper investigates the scope of utilizing biodiesel developed through the butyl ester from Pongamia oil and linseed oil as an alternative fuel source for a C.I engine. The common problem arises while using neat vegetable oils in C.I engine are due to its higher viscosity. To eradicate this problem, a process named transesterification is done. In this current investigation the performance characteristics of a 20% of methyl ester, 20% of ethyl ester & 20% of butyl ester of Pongamia pinatta (MEOP,EEOP,BEOP) and Linseed oil (MELO,EELO,BELO) with 80% of diesel is studied. Hence this investigation ensures the suitability of butyl ester blend as fuel for CI engines without any modification. © 2015 Elsevier B.V., All rights reserved.