Air filter Airbox clamp
Cam cover breather hose
Air filter housing rubber seal
Air filter rubber trunking
Carburettor airbox gasket
Performance air filtration
Carburettor steady bar bush
In the GTA, radical changes were made to the Bialbero to make it suitable for racing
Both the inlet and exhaust cam operated bucket-style followers directly on top of the valves angled at 80 ° to one another, with tappets adjusted by shims. It produced 80hp at 6300 rpm breathing through a twin-choke carburettor. It was a pretty engine above and bellow too, with its U-shaped cam cover on top and a wide and intricatelyfinned cast aluminium sump underneath.
This initial engine was first available in 1954 and set the blueprint for the Alfa Twin-Cam. Just eight years after the Twin-Cam was launched, Alfa made some fundamental changes. In 1962, Alfa released the replacement for the Giulietta, the boxier and sleeker Giulia. This new car came with the updated Twin-Cam, now with a 1567cc. While they might look much the same from the outside, the newer engine – still an all-alloy unit – uses the same basic concept but the internals of the Giulia’ s engine are almost all different. The valve stem increased by 1mm to 9mm, the bore centre spacing was increased, the crankshaft was redesigned and the timing chain was made longer. The changes were created to improve manufacturing, but they also released more power. The very first 1600s produced 92hp with a single carb and 109hp on two twin-choke carburettors. It’ s the later engine with the larger bore spacing that forms the basis of most of the subsequent development until 1994 when the Twin-Cam’ s production ended.
There’ s one thing Alfa’ s Twin-Cam is famous for: the way it sounds. Paul Dove, from Alfa engine specialist Bob Dove Motorsport, who has worked with Nord engines for 20 years agrees.‘ It has a distinct noise. A really nice noise on part throttle or when you load them up. From the sixties, almost all of them came on twin Webers. A twin cam engine on twin Webers in 1963, 64 was a pretty high-end thing, in a production car at least.’
22 The Engine Rebuilder Issue 01