The Toyota AZ engine family is a straight-4 piston engine series. The AZ series uses an aluminium engine block with cast iron cylinder liners and aluminium DOHC cylinder head. The engine series features many advanced technologies including slant-squish combustion chambers, offset cylinder and crank centers, and the VVT-i continuously variable intake valve timing system. The aluminium engine measures 626 mm (24.6 in) long, 608 mm (23.9 in) wide, and 681 mm (26.8 in) tall.

The Toyota S Series engines are a family of straight-four petrol engines with displacements between 1.8 and 2.2 litres, produced by Toyota Motor Corporation from January 1980 to August 2007. The S series has cast iron engine blocks and aluminium cylinder heads.