Daihatsu A-series engine

The Daihatsu A-series engine is a range of compact two-cylinder internal combustion piston engines, designed by Daihatsu with the aid of their owner Toyota. Petrol-driven, it has cast iron engine blocks and aluminum cylinder heads, which are of a single overhead cam lean burn design with belt-driven camshafts. The head design was called "TGP lean-burn", for "Turbulence Generating Pot". The engine also had twin balancing shafts, which provided smoothness equivalent to that of a traditional four-cylinder engine - although it also cost nearly as much to build.

The engine was developed with some haste in order to replace the two-stroke "ZM" engines used in Daihatsu's earlier Kei cars, and was the first unit to take full advantage of the new 550 cc displacement limit in effect from 1 January 1976. It was first presented in May 1976 as the AB10. Eventually, even a turbocharged version was produced. The engine was replaced by the three-cylinder EB-series in 1985.