1927 Minerva AF

Société Anonyme Minerva Motors was an automobile company established in 1903 by Sylvain de Jong, a manufacturer of bicycles and motorcycles in Antwerp, Belgium. In 1908, they obtained a license to produce engines in the Charles Yale Knight sleeve-valve design, and from that point forward - until the end of production in 1939, all Minerva cars were equipped with sleeve-valve engines.

In both Europe and the United States, Minerva - the 'Goddess of Automobiles' - was popular with film stars, politicians and industrialists alike. Success in the United States was partially attributed to Paul Ostruck of New York, who maintained a strong agency for the marque as part of his 'The Consolidated Foreign Motor Car Co.' in the mid to late 1920s.

Minerva's reputation was built around its craftsmanship, build quality, and advanced engineering. It shared its ingenious cantilevered rear leaf-spring suspension with the Rolls-Royce, and its generous wheelbase sizes were among the largest offered.

During the German occupation, Minerva relocated to Amsterdam, where they maintained development of their automobiles. They returned to Belgium in 1920 and restarted the production of luxury cars with the 3.6-liter four-cylinder 20CV and the 5.3-liter six-cylinder 30CV models. A second factory was opened in 1922, smaller models were added to the lineup in 1923, and in 1927, the 30CV was replaced with the 6-liter AK. Around the same time, a new 2.0-liter six model dubbed the 12-14, was introduced. In 1930, the company introduced a straight eight engine available in two sizes: a 4.0-liter AP and the 6.6-liter AL. The final Minerva model was the 2.0-liter M4 of 1934.

Charles Yale Knight
Charles Knight of Indiana was dissatisfied with the noisy poppet valves, so he designed an engine that used a pair of concentric cast iron sleeves, or tubes, interposed between the pistons and cylinder block with pistons sliding on the inner sleeves. These sleeves were reciprocated by short connecting rods operated by a crankshaft-rotated eccentric shaft much like a camshaft. This engine design was more expensive to manufacture, and added reciprocation mass and extra friction made the engine harder to turn over for starting. The benefit: the engine operation was much quieter.

The Minerva Model AF
The Minerva Model AF was introduced in 1926 and initially came equipped with a 5.3-liter (5,343cc), 6-cylinder, 30CV Knight Sleeve Valve engine with 150 bhp. Engine displacement later grew to 5,954cc, and with a Zenith two-barrel carburetor, output rose to 100 hp. The transmission was a four-speed unit with a double-side chain drive, and braking was via four-wheel drums with Dewandre Vacuum-Servo Assist. The 149.5-inch wheelbase, double-drop frame chassis was suspended by a solid front axle, a liver rear axle, and semi-elliptical leaf springs.

The AFS, with the 'S' representing 'Sport,' resided on a shortened chassis and was often fitted with sporting coachwork.

by Daniel Vaughan | Mar 2024