This motor used sodium-filled valves and was adapted to use an offset piston pin to reduce piston slap. Then in 1971 a 2-litre( 1962cc) version was available, it shared the same stroke as the 1779cc engine( 88.5mm) but the bore was increased from 80 to 84mm. The 2-litre made 132hp at 5500rpm.
Prominence in historic motorsport and an endless number of fast-road modified Bertone GT coupés, have convinced us that this Twin-Cam is almost perfectly suited to motorsport. Paul explains that’ s not the case,‘ As a race engine, it’ s not that good. You know, when they raced the GTAs, they were using twin plug heads. So they’ ve designed a different cylinder head.’
Alfa made radical changes to the Twin-Cam’ s head to make it suitable for racing and its homologation special, the lightweight aluminium-bodied GTA. Instead of creating a four-valve head, it increased the size of the valves into the space where the centrally-mounted spark plug was located. To counteract the less optimal offset spark plug, it added another to make sure flame propagation was sufficient and in doing so created a twin-spark head.
The twin-spark is the race engine that made an impact and was used in the later wide-body 1300 GTA that competed in smaller-engined classes and championships. The eight-spark plug head was also added to the 1750 GT Am’ s 2-litre engine, too.
Cylinder head
Valve guide seal
Valve guide
Cylinder head bracket
Half moon rubber seal
26 The Engine Rebuilder Issue 01