All versions were four-cylinders with aluminium block, three-bearing crankshaft and wet liners, which were made in various bores to allow variety of displacements.
In 1993, this engine became available with Bosch single-point injection system and a catalytic converter.
In 1996, the engine was further modified to meet Euro 2 emission standards: modifications included a multipoint injection system, larger camshaft bearings, and larger intake/exhaust valves, which further improved power output and efficiency of engine.
As there was no need for a distributor (MPI using an ignition module mounted to the cylinder head), the valvetrain cover (hitherto unchanged since 1964) could be made narrower, moving the accessory belt closer to engine.
The injection system was upgraded, now using two lambda probes and a drive-by-wire throttle valve.