The Morris Garage Model B -- or MGB --was introduced in 1962 and continued until 1980. It was a classic, affordable British sports car. The MGB was equipped with a 1,798 cubic-centimetre, inline-four-cylinder engine. This engine was often called the 1800 cubic centimetre, and essentially remained the same throughout MGB's production lifetime. MGB engine identification relies on locating and decoding the engine number, but MGB engines were not dated. Determining the date of an engine cannot be positively accomplished without contacting an MGB professional.
Locate the MGB engine-number on the right-hand side of the block, just below the middle two spark plugs. A typical MGB engine-number reads "18G-U-H101."
Write down the MGB engine number for future reference. This number is important when ordering parts, and for comparison with other vehicle numbers.
Decode the MGB engine number. According to the MGB engine number key -- on the MG Cars site -- the example, "18G-U-H101," breaks down as follows. The "18" identifies the 1800 engine, and "G" stands for MGB. The "U" identifies ancillary changes to the engine. The "H" indicates a high-compression engine. The remaining number -- "101" -- is the engine's consecutive serial number.
MGB Cars provides a list that matches engine numbers to the MGB model in which the engine was originally installed. MGB Models include the two-seat touring car, or the MGB-GT.