The straight-six engine is making a resurgence. BMW has always carried the straight-six torch, though the likes of Nissan, Volvo, and Mercedes-Benz all have historical inline-six connections, too. Today, you’ll find more straight-six options than at any other point in recent history, with models like the RAM 1500 RHO, Mazda CX-90, and Land Rover Discovery all offering modern straight-six power under the hood. Last month, we brought you a story about how only seven manufacturers are still building straight-six engines. Now, we’re adding an eighth company to the list but with a major caveat. Read on.
The enthusiast driver’s love of the straight-six engine transcends generations. Below, we’re meeting a “supercar” engine from the 1930s that’s been un-retired after literally sitting in storage for decades. This particular inline-six love affair dates back 90 years to 1936, when the 4.3-liter unit was sold as a performance powerhouse with military durability and incredible smoothness. The powerplant propelled some of the fastest and most innovative British cars of the day.
The Alvis brand ceased operations in 1967, but not before earning a reputation as a design and innovation powerhouse that once marketed cars with slogans like “Ten Years Ahead Of Its Time.” By the time the company closed, it had ignited an early passion for straight-six power among enthusiast drivers, developed many innovations we take for granted today, and even indirectly influenced the original Mini Cooper. Today, the Alvis Continuation models are carrying the brand’s history forward, and a legendary straight-six is the star of the show.
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Meet The 4.3-liter Straight Six From 1936
The Alvis Car Company’s technological achievements in the 20s and 30s eventually culminated in a new platform powered by what amounted to a supercar by 1930s standards. A massive 4.3-liter straight-six engine with 137 hp was up front, and it bolted to the world’s only all-synchromesh four-speed manual driving the rear wheels. This rear-drive platform with independent front suspension underpinned some of the fastest and most sophisticated cars of the day.
In 2021, the 4.3-liter straight-six engine was resurrected, along with a smaller 3.0-liter unit, as part of the Continuation Series from Alvis. Currently, the Alvis Graber (below) is the only continuation model to use the 3.0-liter engine. The remaining models (Vanden Plas, Bertelli, Lancefield and Park Ward) all run the 4.3-liter unit.
Picking up where the brand left off in the late 1960s, the Continuation Series cars brought the 4.3-liter straight-six engine back to life in a resurrection like no other. Rather than installing a modern engine, the Alvis Continuation cars would use original engine blocks and thousands of other parts that had been in storage since the brand’s final days.
Before these castings are granted a new lease of life, each one undergoes thorough scrutiny: a visual inspection, crack and pressure testing for coolant integrity and precise dimensional examination. Other internals, such as conrods, camshafts, and pistons, also come from Alvis’ extensive inventory, which already supports a global network of over 4,500 Alvis cars still on the road. Some are original stock, while others have been remanufactured by reverse engineering existing parts, using an enormous archive of 25,000 drawings and diagrams.
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The first continuation cars sold with the 4.3-liter engine, like the Vanden Plas (above), were built using off-the-shelf original engine blocks. Today, the 4.3-liter engine block itself is custom-made for Alvis, entirely to the original specifications and technical drawings. The original iron cylinder head is now aluminum for better heat dissipation. A modern 20w50 multi-grade engine oil is the standard lubrication.
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Alvis Straight Six |
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Engine |
4.3-liter straight six-cylinder gas na |
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Injection |
Alvis Fuel Injection |
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Power |
170 hp @ 4,400 rpm |
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Transmission |
4-speed manual, all-synchromesh |
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Top Speed |
119 MPH (recorded 1936) |
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0-60 |
7.5-10 seconds |
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For emissions compliance, the continuation engines get electronic fuel injection and improved compression ratios enabled by modern machining and manufacturing processes. This helps take horsepower from the original 137 hp up to 170 hp for the continuation version.
While faithful to the original engines, the modernized units offer more refined performance and emissions compliance. They are designed to start fast with the tap of a button. The powerplant’s internals include a one-piece, seven-bearing forged crank designed especially for the engine produced in the UK. There’s also roller rocker valve gear and forged pistons.
Interestingly, Alvis says that their continuation engines weren’t designed with increased power in mind, but that the adoption of closed-loop fuel injection, better machining tolerances, and the precise air/fuel mix control required for emissions naturally improved refinement, power, driveability, and fuel economy. It’s a more refined version of a period-correct engine.
The transmission has also been updated, with the early all-synchromesh four-speed box replaced by a five-speed Tremec in the 3.0-liter chassis and a six-speed Tremec in the 4.3-liter cars. There’s now power steering, too.
Owning a modern Alvis isn’t cheap. The cost of this straight-six journey starts at around $437,000 for the Alvis Vanden Plas, including a three-year warranty on the hand-built engine.
A Brief History Of The Alvis Motor Company’s Innovations
The year is 1900. The honeycomb-style automotive radiator hit the scene for the first time after its introduction by Wilhelm Maybach. This world’s first high-performance engine cooling system quickly helped automakers unlock the potential of the combustion engine, making cars faster and more convenient. By 1912, electric engine starters started to appear. By 1920, the industry had endured a war, and a transfer of knowledge from wartime production saw automakers of the day applying new technologies, materials, and approaches to building modern cars.
Advances abounded in lightweight engineering and materials science. Manufacturing became smarter and more flexible. The closed-body car was becoming trendy, and four-wheel hydraulic brakes were hitting the scene. It was early days, but cars were now on a rapid path of becoming faster and more luxurious than ever. Plus, there was a growing market of folks who were itching to get out and drive.
Amidst all of this, Thomas George John founded the Alvis Car Company in 1919. In 1920, the company started manufacturing its first car in Coventry, England. It was called the 10/30 and made 30 horsepower. A 2-3-seat model with a rumble seat cost £561 (including tax). According to the Bank of England’s inflation calculator, the price equates to £21,871.50, or $29,390 today.
Alvis focused on design, engineering, and hardware, as well as manufacturing the rolling chassis of each vehicle. The coachwork bodies were supplied by the top manufacturers of the day, allowing Alvis to focus more intently on engineering and technology. In this era, cars like this were for the wealthy, who would often purchase the rolling chassis from a company like Alvis and then pay even more to have the coachwork installed elsewhere. As with the Bertelli (pictured below), the body is built to the customer’s exact specifications.
In 1923, Alvis signaled the “Dawn of a New Motoring Era” with the launch of the 12/50, a 50-hp two-seat sports model. The same year, Alvis won the 200-mile race at Brooklands, kicking off competitive successes and a good share of the performance car spotlight of the day.
By 1925, Alvis was designing and manufacturing everything in-house, running a design office, foundry, pattern shop, machining shop, and rolling chassis assembly facility, in addition to marketing and sales. Also, that year, Alvis became the first automaker in the world to design and race a front-drive car. It marketed front-wheel drive towards a driver keen on participating in the emerging pastime of motorsports.
In 1926, Alvis introduced the 12/80. It was an 80-horsepower supercharged sports car with front-wheel drive and a polished aluminum body. In the day, Alvis literature claimed that the modern “speedy driver” knew the benefits of front-wheel drive all too well, and that the 12/80 lived up to the brand’s motto of being “Ten Years Ahead Of Its Time.”
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Before long, Alvis successfully combined experimental supercharged straight-eight engines with its front-drive technology to finish first and third in class (6th and 9th overall) at the 1928 24 Hours of Le Mans. This kicked off the production, design, and manufacturing of front-wheel-drive cars that would prove to be a pinnacle of the brand’s technological legacy.
By the time the 1930s arrived, Alvis was gaining even more recognition for innovation. The Speed 20 launched in 1931 with a “genuine 100-mile-per-hour chassis.” In 1933, Alvis created the world’s first all-synchromesh gearbox, giving drivers a quieter, smoother drive to rival that of the world’s finest cars. The business began work on the first independent front suspension next, a technology that Bentley didn’t introduce for another six years.
Decades after Alvis’s early front-wheel-drive innovations, the famous automotive designer Alec Issigonis joined Alvis and took an interest in the FWD design. He was heading a project to design a prototype 3.5-liter V8 and associated suspension for a front-drive platform that never made it to production. In 1959, Issigonis, who was known to be fascinated by front-drive cars, joined the British Motor Corporation and went on to produce the iconic BMC Mini.
Sources: The Alvis Car Company, Bank of England
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