In 2024, the six-cylinder engine has seen somewhat of a resurgence in a variety of different uses. Throughout most of the 20th century, the six-cylinder tended to be seen as the more affordable option for performance cars. While still producing solid power, the engines were more fuel efficient than the mighty V8s that found favor in high-end sports and muscle cars.
As a result of tightening emissions regulations, and the increased price of fuel, over the years, six-cylinder engines with the help of turbocharging are immensely common in a range of modern-day performance cars. Most have displacements of under four liters, so HotCars decided to search for the largest displacement six-cylinder powerplant ever produced for a production car.
The 1912 Oldsmobile Model Z Featured A Monstrous 11.6-Liter Inline-Six
Discovering the most massive engines sometimes requires looking back more than a hundred years to when automobiles first emerged. During the early 1900s, engine engineering was primitive compared to modern standards, and forced induction systems like turbochargers and superchargers hadn’t been invented yet. Without these technologies to boost power output, manufacturers faced a significant challenge in creating engines capable of reaching respectable speeds. The solution was straightforward: increase the engine’s displacement.
While many powerplants from this era dwarfed today’s typical four-liter engines, none matched the extraordinary creation from Oldsmobile’s ambitious engineering team in 1911. They successfully developed a massive straight-six engine displacing 11.6 liters—or 707 cubic inches. This behemoth powered the Model Z Limited, Oldsmobile’s ultra-luxury offering that served as the era’s equivalent of a modern limousine. The company aimed to provide its wealthy clientele with the most advanced and impressive technology available.
When the Model Z Limited debuted in 1910, it featured a 505 cubic inch version of this engine architecture. However, Oldsmobile’s engineers were determined to extract even more performance, ultimately expanding it to its final 707 cubic inch configuration for the 1911 model year. The colossal engine produced 60 horsepower—a figure that might seem modest today but was considerable for the period, especially considering the power traveled through enormous 42-inch wooden wheels to reach the pavement. This was according to RM Sotheby’s, the auction house that sold the sole surviving 1912 Touring model for $3.3 million.
The impressive engine sat up front and delivered its power to the rear wheels via a four-speed manual gearbox. With just 140 units manufactured in 1912, the Limited holds the distinction of housing the largest-displacement production six-cylinder engine ever made, while also ranking among the most exclusive vehicles of its time.
Hudson Also Made A Sizable NASCAR-Derived Straight-Six
While there were other super-sized six-cylinder engines in circulation during the early days of motoring, such as a 6.6-liter straight six used by Ford in its Model K between 1906-08, there is very little information regarding the make-up of the units. There is, however, much more information about a particularly large six-cylinder powerplant that originated in the early 1950s.
The engine in question was designed by Hudson, which was looking to dominate NASCAR. The brand secured three successive championships with its Hornet model between 1951-53, with a large portion of its successive coming as a result of its 5.0-liter, or 308 ci, six-cylinder Twin H-Power engine. Producing 160 hp, Hudson claimed, quite rightly, that it was the largest six-cylinder engine in production at the time.
The ‘Twin Power’ aspect of the name represents the twin-Carter one-barrel carburetors featured on the engine, which was offered as an option in 1951 before becoming standard for all Hornets in 1952, as per Hemmings. The standard version of the engine, which produced 145 hp, featured a sole two-barrel carb.
The brand included several advanced methods to ensure the powertrain was up to the job of succeeding on the track, as well as in its road-going Hornet models. The cylinder block was made from a chrome alloy material, which made the component stronger and more durable over years of use. The cylinder head, meanwhile, was made using Hudson’s Miracle Dome technology, which was made of light and tough aluminum. Exhaust manifolds and an air intake made from cast iron were also included in the package.
The twin-carb setup was advanced in that it could distribute fuel to the cylinders equally, a system that author Richard M. Langworth described in his book The Postwar Years: Hudson. The marque had been working on perfecting the dual-carb and manifold system since 1937, and the result was that it could accurately measure the amount of gasoline needed, before then dividing it out equally between the six cylinders. The effect of this was that the fuel-air mixture was more easily vaporized by the powerplant, ensuring it could breathe better, and thus produce more power.
Hudson Twin-Power Engine Had More Secrets Included
While the Twin Power system ensured the engine ran as smoothly as many large-capacity V8s used by its rivals at the time, Hudson also made sure the rest of the engine was up to the task. Its crankshaft was forged in position with the help of integral counterweights, which helped to make sure the part was balanced when at rest or while in action.
The pistons were also made of aluminum to keep weight down, and the components were also chrome-sealed to produce extra power. They each had a total of four-piston rings, which helped to reduce vibrations and, therefore, damage, over sustained use. Stronger manganese-alloy connecting rods were included, while crafted camshafts made up of, take a deep breath, nickel-chrome-molybdenum-iron alloy allowed it to have optimal tensile strength.
The engine was further refined for the 1954 model year so that it produced 170 hp, the last year it was used before Hudson merged with Nash-Kelvinator to create what would become AMC, which would go on to create some awesome muscle cars of its own. This was made possible with the addition of what the brand called ‘Super Induction’ technology. While producing a little more power than the unit that preceded it, the system also quickens up the power delivery.
The key to the system was a redesigned combustion chamber compared to the first version of the engine, which improved how efficiently the fuel/air mixture could be used. The engine was peppier at all speeds, up and down the rev range, improving its responsiveness across the board.
Both engines outlined are products of a time that tended to side with the old adage of ‘there’s no replacement for displacement’, which has been well and truly buried during the development of modern engines. Still, they both offer a fascinating window to the past that shows just where the current amazing powerplants originated from.
Sources: RM Sothebys, Hudson, NASCAR, Hemmings, Mecum Auctions
About the Author
