Mitsubishi Motors Engines - Explanation of Codes

Explanation of Codes

Mitsubishi engines designed since 1970 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-4 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. 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.