The Wolseley WD1 was the start of a production run of engines that would continue until engine production ceased. Introduced in 1943 the WD engines were initially produced for the Ministry of Supply 'War Department' at the advent of World War 2. These engines were to be shipped to the desert for use under arduous conditions for a variety of tasks. The WD engines were made available to the agricultural market in 1943 and gained popularity within the farming community as a low maintenance, economical and quiet engine. The silencer supplied with the engine was of a specification laid down by the War Department and remained in use throughout the production run. The WD1 was available in two sizes, 1.5 HP at 700 RPM & 2.5 HP at 1000 RPM. The engine speed could be altered to meet a range of duties by simply turning the governor control knob on the side of the engine. Ignition was by the Wico A series magneto, easy starting being facilitated by an impulse mechanism to provide a strong retarded spark. Production of the WD1 ceased in February 1945 with the introduction of the WD2 with familiar finned water hopper. Around 3,500 engines were manufactured in total. Quite a few have survived into preservation today.