This is a list of engines produced by Mitsubishi Motors since 1964, and its predecessors prior to this. Explanation of codes The Mitsubishi zaibatsu had been broken up into three companies by the US occupying forces. Automobile and truck engines were mainly built by three branches of one of these companies, Central Heavy Industries (Shin-Mitsubishi Heavy Industries from 1952). These three branches (Mizushima, Nagoya, and Kyoto Engineering Works) were established as clusters of the many small aircraft factories built during the war. Thus, Mizushima developments gained the ME code, followed by a numerical, while engines developed in Nagoya became the NE-series and Kyoto-developments were named KE. The numbers do not in any way relate to each other or across letter codes and were purely issued in order of development. In 1964 the three companies were merged into Mitsubishi Heavy Industries and eventually a new naming system emerged. Since the introduction of the 2G10 engine in October 1968, Mitsubishi engines use a four-digit naming convention: The first (digit) signifies the number of cylinders; "2" = straight-2, "3" = straight-3, "4" = straight-4, "6" = V6, "8" = V8. The second (letter) formerly referred to the fuel type; "D" = diesel, "G" = gasoline. However, since the 1980s, this has changed. Two engine families were introduced using the letter "A" to denote that all the engines in the family had an alloy cylinder head. Their latest engines, however, do not follow any previous conventions (e.g. 4M4, 3B2, etc.). The third (digit) previously denoted the engine family. Five of the "4G" straight-four engine families had distinct names; "4G1" = Orion, "4G3" = Saturn, "4G4" = Neptune, "4G5" = Astron, and "4G6" = Sirius. The fourth (digit) is the specific engine model within the family, issued in order of development. It is not a guide to its place within that family, nor is it a guide to the capacity of the engine. There may also be supplementary letters after the initial four characters. "T" can indicate that the engine is turbocharged (e.g. 4G63T), "B" that this is the second version of the engine (e.g. 4G63B). Where engine codes are used which include the supplemental letters, the first digit denoting the number of cylinders may be omitted, so 4G63T may be seen as G63T. Configurations Single-cylinder These were used in Mitsubishi's very first vehicles, motor scooters and three-wheelers. A-series — A 744 cc air-cooled OHV