The Toyota ZZ engine family is a straight-4piston engine series. The ZZ series uses a die-cast aluminum engine block with thin press-fit cast iron cylinder liners, and aluminum DOHC4-valve cylinder heads, a first for Toyota.The camshafts are chain-driven. The two 1.8 L members of the family, the 1ZZ and 2ZZ, use different bore and stroke. The former was optimized for economy and torque, while the latter is a "square" design optimized for high-RPM power. The ZZ family replaced the extremely popular cast-iron block 4A engines.
Toyota engine names are interpreted as follows. The leading number denotes the generation, and the next one or two letters, followed by a hyphen, specify the engine family. The remaining letters, following the hyphen, describe the engine's major features. For example, the 2ZZ-GE can be decoded as being the second generation of the ZZ engine series and features a performance-oriented cylinder head with widely angled valves (G) and electronic fuel injection (E).[