Diesel engines are the prime movers that are highly efficient compared to their counter part of petrol engines. However, higher NOx, particulate matter CO, HC are the draw backs associated with their operation. Renewable fuels like biodiesel and their blends are suitable and substitute for different applications as they are renewable in nature and provide satisfaction for fossil fuels of diesel which are exhaustible in nature and add burden to the Indian economy. In this direction the experiments were planned on the modified diesel engines to study the effects of Dairy scum oil methyl esters B20 blend (DSOME B20). By Advancing the time of injection from 19° to 27° BTDC, keeping injection opening pressure IOP constant results are obtained and analysed. It is noticed that higher BTE, lower emissions of smoke, HC, CO emissions while NOx increased.