1939 Mercedes-Benz 540K

The 1930s birthed some of the greatest automotive creations to ever put rubber to the road, with state-of-the-art, competition-inspired chassis coupled with potent engines, and luxurious and stylish coachwork. The most noteworthy production models from the Stuttgart firm during this era were the 500K and its successor, the 540K. The Mercedes-Benz 540 was a development of the 500K and shared its independent suspension chassis paired with a 5.4-liter supercharged straight-eight engine. It was one of the first models developed under the company's new chief engineer, ex-racing driver Max Sailer, successor to Hans Nibel, who had died in November 1934. Quality, elegance and comfort were the primary concerns.

Launched at the Paris Salon in October 1936, the 540K was one of the few genuine 100 mph road cars available in the 1930s. The Roots-Type supercharger system became engaged when the accelerator pedal was fully depressed, engaging the compressor and closing off the alternative atmospheric intake to the carburetor. This was not the first use of this system as it had been thoroughly proven on the preceding series of Dr. Ferdinand Porsche-conceived S cars that had dominated racing during the 1920s. The 540K became the final supercharged production Mercedes until relatively recent times.

Chassis
The Mercedes-Benz 540K, a development of the 500K, itself an evolution of the SSK, was offered as a two and four-seat cabriolet, a four-seater coupe, and even a luxurious seven-seater limousine. Though based on the preceding 500K chassis, the girder-like frame was lightened with oval-section tubes late in 1938, with its design inspired by the company's Silver Arrow competition models. The stiff chassis was suspended by a fully independent setup with coil springs and a camber compensator spring offsetting the swing axle independent rear suspension's tendency to sudden camber changes. Wheelbase sizes included a 117.3- (2980mm / SWB), a 129.5- (3290mm / Normal), and 152.8-inch (3880mm / Special) platforms. The 'Normal' chassis served as the platform for the four-seater cabriolets, the 'B' with four side windows and the 'C' with two side windows. It was also used for saloons and touring cars. The shorter chassis carried the two-seater cabriolet 'A'. The 'Normal' had its radiator positioned directly above the front axle while the shorter platform had its radiator, engine, and cockpit moved rearward, 7.3-inches back from the front axle.

Engine
The 5,401 cubic centimeters (329.6 cubic inch / 5.4 liter) straight-8-cylinder engine was fed via twin pressurized updraft carburetors and produced 115 horsepower without the supercharger and 180 horsepower when it was engaged. The adoption of sodium-cooled valves followed the company's highly successful racing practice. While many superchargers drew from the carburetor, the Mercedes type blew through the carburetor. It did not run all the time but was activated on demand when the accelerator was flat on the floor. Power was sent to the rear wheels through a four-speed or optional five-speed manual gearbox with synchromesh on the top three gears. Stopping power was by vacuum-assisted hydraulic brakes at all four corners.

Coachwork
Mercedes-Benz's Sindelfingen coachbuilding factory employed approximately 1,500 people which meant that most of the 540K models wore factory coachwork. Among the list of independent coachbuilders who created bodies for the 540K included Windovers, Mayfair Carriage Company Ltd., Erdmann & Rossi, and Norrmalm.

Production
Mercedes-Benz delivered 419 examples of the 540K during its production lifespan from 1935 to 1939, a slight increase over the 342 examples of the 500K. Most were bodied by Sindelfingen with 70 created as rolling chassis. Combined 500K and 540K production included 6 as Autobahn cruisers, 12 coupes, 28 open cars (Tourenwagen), and 58 roadsters. 116 examples wore Cabriolet A coachwork, 296 as Cabriolet B, and 122 with Cabriolet C bodies. Most of the 23 saloons with 4 doors were 500Ks and most of the 29 saloons with 2 doors were 540Ks.

97 examples were produced in 1936, 145 in 1937, 95 in 1938, and 69 in 1939 before the war ended series production.

by Daniel Vaughan | Oct 2022