Alfa Romeo Twin Cam engine

The Alfa Romeo Twin Cam, known in Italian as the bialbero and nicknamed the Nord engine, is an all-aluminium inline-four that Alfa Romeo produced from 1954 to 1994. Designed by Giuseppe Busso, it debuted in the 1954 Giulietta at 1,290 cc, with an aluminium block and cast iron wet liners, hemispherical combustion chambers, a forged steel crankshaft on five main bearings and double overhead camshafts driven by a duplex chain. It grew to 1.6 litres for the 1962 Giulia, 1.8 litres in 1968 and 2.0 litres in 1971, and was adapted for the Alfetta. In 1980 the Spider received an electro-mechanical variator, making the Twin Cam the first production car engine with a form of variable valve timing. Autodelta also built competition versions.