Four Valves Good, Two Better
I enjoyed very much Andrew Frankel’s article in the November issue on the Ferrari 500.
Colin Cambell, in his book The Sports Car – Its Design and Performance writes: “Only the genius of a Lampredi could provide this engine with a crankcase to cope with such an extreme stroke/bore ratio”. Incidentally, the first Testa Rossa, appearing in 1956, was a four-cylinder 2-litre.
In late 1955, Aurelio Lampredi left Ferrari for Fiat. Lampredi’s first twin-cam for Fiat appeared in 1966, fitted to the Fiat 124 Spider, using a toothed belt drive. In 1981, Morgan fitted the 1585cc engine from the Fiat 131 to the 4/4 and, in 1984, the 1995cc engine to the Plus Four. In my view these are still the best production 4/4 and Plus Four yet built.
The double overhead camshaft engines with two very large valves per cylinder, directly actuated, was initiated by Fiat in 1921 and widely disseminated ever since, mainly by the great Italian automobile engineers. In your article last year, ‘The world’s greatest racing cars’, I was surprised that the Fiat Tipo 804 of 1922 (six-cylinder 2-litre) did not rate a mention. In the French Grand Prix, the Fiat was almost one hour ahead of the next car and almost 15% quicker, frightening away the opposition for the rest of the season.
One big valve can admit more charge than two or more small ones. My considered view is that two valves per cylinder will again replace four valves; with twin spark plugs, exhaust valves of exotic material, and variable valve timing.
I am, yours, etc. Brian Cowell, Hucclecote, Gloucester