The conventional diesel fuels are depleting at a faster pace. To reduce the burden on the economy, the reserves and sources for future has to be limited. The use of biodiesel derivatives from various sources and its blends in diesel engine has gained more importance in recent years. The present work investigates the feasibility of using dairy scum methyl esters (DSOME) of B20 blend in a modified single cylinder of common rail direct injection (CRDI) engine at a constant speed. Experiments were carried out at different injection timings from 25 BTDC to 5 ATDC with constant injection pressure as 600 bar. The fuel injection timing plays an important role in evaluating the performance, emission and combustion characteristics of the engine. The results show that the performance is improved with retarded injection timings compared to the operation of single cylinder DI engine fuelled with DSOME B20 biodiesel.