The minor 1 was the smalest engine produced by Mamod made. It was introduced in 1939. The Minor 1 was the cheapest engine in the Mamod range. Through the year the engine had several changes. It started as a flat base engine with a wick burner and disc flywheel, Through the years the engine evolved, It got a raised base, a solid fuel burner and a spoked flywheel along with some other smal changes. The Minor 1 was discontinued in march 1979 when it was replaced by the SP1. These engines are quite often to be seen at ebay, and can be picked up for quite reasonable prices, depending on the production period and condition.