The following brief article by Stuart Birch, European Editor, was published in the August 1993 edition of Automotive Engineering.
Alfa Romeo has long been renowned for producing outstandingly good engines, often incorporating fine technology. Now the company has updated its successful 164 saloon, spending half the money allotted to the project on giving the car's already excellent short-stroke , 3.0-L V6 engine four valves per cylinder. Alessandro Piccone, chief engineer, said switching to multiple valves meant, in essence, a complete engine redesign which required some 50 bn Lire (close to $40 million). In multivalve form, the 164 becomes the Super and gets a Bosch Motronic M1.7 management system. Power is upped from 135 to 157 kW, with a more powerful Cloverleaf available with 172 kW. The Cloverleaf has greater-diameter inlet tracts and a reshaped exhaust system to improve gas flow. Alfa says the switch to four-valve technology was to increase power output and torque levels without compromising refinement.
The cylinder heads were redesigned to accomodate the four valves in each hemisperical combustion chamber. The engine has hydraulic tappets operated by four belt-driven overhead camshafts. Sparkplugs are centrally located in the combustion chamber roofs and use individual ignition coils. There is a separate crankcase-mounted sensor on each cylinder bank to control ignition timing. The piston crowns are cooled by oil jets on their undersides. Alfa has adopted a 120-A alternator with dual internal ventilation. Emission control includes a double three-way catalytic converter of large, 3.2-L volume with Lambda probe. The 164 Super requires no scheduled engine maintenance for the first 100,000 km other than periodic oil changes. Spark plugs are double-platinum-electrode NGKs and have been designed to have a 100,000 km life.