The engine is a twin-cylinder Ruston Hornsby diesel engine purchased by the miller, Ben Davis, from the Royal Show at Shrewsbury in 1949. It was the 'show model' of the year, delivered to the mill from the Company's Boulton Works in Lincoln in September 1949. The engine is located where the northern waterwheel once existed with a large iron tank filled with water used to cool the engine. A series of belts and intermediate shafts are required to drive the machinery. The black belt on the left is from the diesel engine, the belt on the right drives the overhead horizontal shaft. This then drives the Combined Milling Machine and the Sack Hoist, also a grinding wheel that could be used for sharpening the mill-bills used for dressing millstones. Alternatively, by changing the belting, the diesel engine could be used to drive a saw bench or the very noisy hammer mill, located to the left of the black belt, that the last miller used for his part-time work of grist or animal feed milling. The belts from the diesel engine and to the overhead shaft are twisted to give a greater contact area on the pulley wheels to reduce slippage.

For many years during Open Days the air around the diesel engine would become polluted by the foul-smelling exhaust fumes of the engine. The use of diesel as the fuel has now been replaced by HVO - Hydrotreated Vegetable Oil. Although not yet readily available, we have managed to obtain a supply sufficient for our needs. It has not been necessary to make any changes to the engine and the obnoxious diesel fumes have been completely eliminated.