Production of fatty acid methyl esters from pongamia oil through trans-esterification was reported in this paper. The GC - MS analysis of oil was studied and the major fatty acids content was found to be 12.25% by weight. The molecular weight of the oil was 887.039 g/mol. A maximum yield of 85% biodiesel was reported when the reaction temperature, time, methanol/oil ratio and catalyst loading rate were 60°C, 45 min, 12:1 and 0.5% by (wt. %) respectively. The low cost pisthia shell catalyst was prepared and characterised in the laboratory setup. Partial purification of the fatty acid methyl esters was proposed for increasing the purity of the biodiesel and better engine performance and that was obtained from the oil firm itself. The flash point and the fire point of the biodiesel were found to be 172°C and 225°C, respectively. The brake thermal efficiency of B10 blend of biodiesel was 34% for maximum load, specific fuel consumption for diesel was 0.55 kg/kWhr at maximum load and for the blend of B50. The use of biodiesel blends showed a reduction of carbon monoxide and hydrocarbon emissions and a marginal increase in nitrogen oxides (NOx) emissions. Copyright © 2018 Inderscience Enterprises Ltd.