Mercedes-Benz 540 K Sport Cabriolet A
The 540 K’s story really starts in 1932 with the 3.8-liter Mercedes-Benz 380, which already had the look and the supercharger. However, it was handicapped by all-up weight of 5,000 lbs and a meager 120 hp. This was addressed at the 1933 Berlin Motor Show when the 500 K (Kompressor means supercharger in German, hence the “K”) was launched, the eight-cylinder motor having been enlarged to five liters and delivering 160 hp.
Instrumental in development was Dr. Hans Nibel, who was the chief engineer for Benz before the merger with Daimler and who succeeded Ferdinand Porsche on his departure in January 1929. Nibel had cut his teeth on the enormous Blitzen Benz racers before WWI, and he and Hans Wagner cooperated on the independent suspension of the new 380. His last contribution would be the supercharged 500 K engine, as he died of a stroke soon after in 1934.
Nibel also strove to establish the Mercedes-Benz in-house coachworks, which would become known simply as Sindelfingen, for the town in Germany.
The 380/500 K/540 K employed a massive chassis with huge side-members. Front suspension was by unequal length wishbones with coil springs, while the rear involved swing axles and double coil springs on each side. The engine was cast as a monobloc, with head and block together, and the four-speed transmission was semi-automatic, with pre-select between 3rd and 4th gear. The supercharger was engaged when the accelerator was pressed to the floor, producing an extra 65 hp and a most satisfying howl.
However the 500 K made its mark in competition early on in the 1934 Deutschland Fahrt (Tour of Germany). Covering 1,364 miles through Germany, the factory 500 Ks and private entries dominated the field of 190 cars.
The “look” had been accomplished, with the V-shaped grille moved back from the front bumper, bracketed by trumpet horns and spotlights. With twin exhaust pipes projecting from the side of the hood, the engine was edging towards mid-location and the cockpit set back almost at the rear wheels, but the 500 K still needed more power. The result was the 540 K of 1936.
While small numbers were bodied by custom coachbuilders like Saoutchik in Paris, Erdmann & Rossi in Berlin and even Carlton in England, the definitive style was set by Hermann Ahrens at the company’s subsidiary coachworks at Sindelfingen.
From the 380 to 540 K, Mercedes Benz practiced what may be referred to as ‘running changes’ – when a viable engineering development came along, it was incorporated into the next car built.
It represents one of the earliest road-going uses of the new 5.4-liter motor. According to information provided by Mercedes-Benz Classic Germany, the car belongs to Series 29 08, in which the first 5.4-liter motors were utilized. The coachwork, meanwhile, is of series 820600, for which ten bodies were built, five with five-liter motors and another five with 5.4-liter motors. Chassis 130945 is therefore a very transitional model with a sleek, low-beltline body and the newly introduced 540 K motor.
Consequently, the evolution of the name 540 K Sport Cabriolet came into being, separating them from the other cars labeled Cabriolet A. It is one of the earliest 540 Ks and one of six “in transition” Cabriolet models. As a result, it has the horizontal hood louvers of the 540 K but both spares are on the trunk, instead of one being recessed like the 1937 540 K Spezial Roadster. It also has an exceptionally low windshield and the long open fenders typically seen on the Spezial Roadsters.
This car was auctioned off by RM Auctions in August of 2011 at the Portola Hotel & Spa and Monterey Conference Center, Monterey, California and in May of 2012 at the Grimaldi Forum, Monaco.
180 hp, 5,401 cc, OHV supercharged straight eight-cylinder, four-speed manual transmission with pre-select on 3rd and 4th gear, independent front suspension by unequal length wishbones and coil springs, rear swing axles with trailing arms and coil springs, four-wheel vacuum-assisted hydraulic drum brakes. Wheelbase: 129.5"
Source: RM Auctions
Photo Credit: Copyright Glenn McLaughlin and Steve Giraud