The simplest engine ever

The simplest engine ever

( – If the walls of the Mirafiori building and the headquarters and all the other offices of Fiat could talk, they would certainly have stories to tell about the background of the construction of the most famous cars of the Turin brand and how As the engineers invaded. their minds to meet the needs, especially in terms of cost.

Fiat 500 Topolino (1936-1955)


One of these stories, perhaps the most famous that is still told today, concerns the brand’s first small car and the first “modern” car. We are talking about the first Fiat 500, born in 1936 and called “Topolino” because of its Mickey Mouse headlights. A true humble gem that started with an engine.

Little effort, big payoff

The need for a small, expensive and widespread car manifested itself in the offices of Fiat in the early 1930s, according to various sources at the direct inspiration of the dictator Benito Mussolini, who wanted to accelerate the movement of cars in the country, like Hitler a. a little later he would do it in Germany by asking Ferdinand Porsche to take the future Volkswagen design.

The work finally fell to the promising young engineer Dante Giacosa, who was given a few features, especially the final price, which at that time did not exceed 5,000 lire (which he did, and quite a bit).

Giacosa created a car characterized by the simplicity of many solutions, from the chassis with two side members with mesh, to the rear suspension with a half leaf spring that came from the members themselves (later replaced by a standard full leaf spring). for physical work. But what stood out was the engine.

natural movement

In order to reduce costs as much as possible, Giacosa distributed all the parts that can be replaced with so-called “natural” movements: so he designed an engine with splash lubrication (the crankshaft and other components lubricated themselves with their own movements) and a very simple oil pump, while those of the cold cycle and oil were completely absent.

Their work was ensured by the careful positioning of the components, in this case the radiator and the tank, both placed on top of the engine: the radiator took advantage of the tendency of hot water to rise towards it, where it was blown by a fan of only four blades rotated 180 degrees, so that only had to pump air from the radiator grille a little.

Instead the fuel was pumped out by gravity, through a hose that could be turned off from the inside, as a small 21 liter tank was located behind the dashboard.

Construction for almost 20 years

The Topolino power plant, after all, was a four-cylinder with a displacement of more than half a liter (569 cc, with a bladder and a stroke of 52 x 64 mm), side valves moved by the camshaft in the crankcase through rods and rockers. arms , and a single 22mm Solex horizontal carburetor.

However, an output of only 13 hp and a torque of around 32 Nm was enough to bring the 3.2 meter long car weighing more than half a ton to more than 80 km/h, which is equivalent to an average consumption of 6 liters per 100. eg it was a very good result.

Production of the Fiat 500 “Topolino” continued for ten years after the end of the Second World War, including three series (from 1948 with integrated lights) and popular and popular commercial vehicle derivatives (Giardiniera and Furgoncino) for a total of more than half a million.

More from Fiat history:

Fiat 126 (1972-2000): The cult midget turns 50
Fiat 127 (1971-1987): Do you remember it?

However, the name 500 and extreme economy was only two years later in the most popular “Nova 500“, also designed by Giacosa, but this time with an air-cooled rear cylinder engine, which also became legendary.