The Alfa Romeo Twin Cam engine is an all-alloy inline-four engine series produced by Alfa Romeo from 1954 to 1994. In Italian it is known as the "bialbero" ("twin-shaft"), and has also been nicknamed the "Nord" (North) engine in reference to its being built in Arese, close to Milan, in the North of Italy and to distinguish it from the Alfa Romeo Boxer engine built in the South (Sud) for the Alfasud. History The Twin Cam's predecessor appeared in the 1950 Alfa Romeo 1900 and was an under-square inline four cylinder with a cast-iron block, an aluminium alloy crossflow cylinder head with double overhead cams and a 90° included angle between intake and exhaust valves. Development of that engine was overseen by Orazio Satta Puliga who would also helm development of its successor. The 1952 Disco Volante had a 2-litre DOHC four cylinder engine with an aluminium block and sleeves, but this seems to have been a custom version of the 1900 engine rather than a prototype of the forthcoming Twin Cam. While the Twin Cam shared some features with the 1900 engine, it was a new design by Giuseppe Busso. The Alfa Romeo Twin Cam engine debuted in the 1954 Giulietta. The engine featured: An aluminium alloy engine block with cast iron "wet" cylinder liners An aluminium alloy cylinder head with hemispherical combustion chambers. A forged steel crankshaft running in five main bearings Double overhead camshafts driven by a double row timing chain Direct valve actuation via camshafts on bucket tappets Two inclined valves per cylinder with a near-centrally located spark plug Inlet and exhaust valves separated by an angle of 80 degrees A large, flat, finned oil sump. These features made the Twin Cam an advanced design for a production car engine of the mid-1950s and would, with minor variations, form the basis of all future versions of the engine. The engine displaced in the 1954 Giulietta. In 1960 another version of the Twin Cam was unveiled along with the Alfa Romeo Tipo 103 small car prototype. This version was noteworthy because, with a bore of , a stroke of and displacing just , it was the smallest four-cylinder Twin Cam ever. Power was at 5500 rpm. In adapting the engine to the transverse front-engine, front-wheel-drive layout the engine block and transaxle case were built as one unit. Only three of these engines were built. On June 27,