Diminishing Returns: The History of 16-Cylinder Engines

November 28, 2022

In many cases in automobile history, more is better. However, there can be an upper limit to how big you can go. One example would be the number of cylinders in an engine, the practical limit is seemingly twelve cylinders.

Decade upon decade, designers have experimented with 16-cylinder engines yet they have never broken through, even though they are a logical extension of both the 8 and 12-cylinder engines. Still, 16-cylinder engines have always been on the fringe and never gained widespread adoption. The push for faster and more powerful cars invited experimentation, which makes an investigation into their history fascinating. 

1930 Cadillac Series 452 (Source: Hagerty)

Caddies and Marmons

In the early days of the automobile, it seemed like everybody was trying everything. There were gasoline, steam, and electric-powered cars. Internal combustion engines grew larger and cylinders more numerous. The first 12-cylinder engine was developed in 1904 for a boat, but it wasn't until 1913 when Sunbeam ran the first V12 engine at Brooklands that they made their way into an automobile.  

The V16 engine did not enter the automotive world in a meaningful way until the late 1920s. We’ll start with the New World where several manufacturers competed to get a V16 into production first. The protagonists were Marmon and Cadillac -- and the battle got heated.

Marmon Motor Company out of Indianapolis gets credit for building the first V16 engine in the U.S. Howard Marmon was a pioneer and pursued a more powerful engine for his line of luxury cars, and he chose to build the world’s first V16. Marmon’s lead engineer, Owen Nacker, started development as early as 1920 and got the first prototype running in 1926. 

Once word got out about the V16, the arms race was on -- and playing fair wasn’t always what was required. Nacker defected to Cadillac in 1927 where he secretly developed their own V16. Cadillac pushed hard to get its car to market before Marmon and was ultimately successful when in 1930 they introduced the Cadillac Series 452, the world’s first production V16. The Marmon Sixteen followed in 1931. Peerless, based in Cleveland, also stole a Marmon engineer to get a V16 into production, but ultimately only produced one prototype.

Both Cadillac and Marmon’s V16s were successful. Marmon’s produced 200 hp from an 8.0-liter which featured an alloy block and overhead cams. The Cadillac V16, as one might guess since they nabbed the key engineer, looked much the same. However, they went with a 7.4-liter displacement that only produced 165 hp -- due in part to the use of only two Stromberg carburetors, one for each 8-cylinder bank.  

At the 1931 Indianapolis 500, Cord entered a car with a custom-built V16 that raced competitively up to third place. Its race was undone by the fact that they needed to change the sparkplugs mid-race -- quite a task when you need to replace 16 of them!

1929 Maserati V4

The European Approach

Motorsports were the animus of the pursuit of the 16-cylinder engine back in Europe. The result was some wildly exotic and creative (although not-so-successful) approaches. 

The inventive Maserati brothers got the ball rolling in 1929 when the Maserati Tipo V4 was built -- making it noteworthy as the first V16 race car. Whereas the Marmon/Cadillac designs were a single-block straight “V,” Maserati tried what in today’s parlance would be called a “hack.” They took two Tipo 26B V8 engines and jammed them into the front of a custom-built chassis. The pair of 2.0L V8s sat side-by-side and had two crankshafts. 

The idea was sound enough in that the V4 set a world record on July 1, 1929, when Baconin Borzacchini averaged an astounding 152.9 mph for 10 kilometers! Subsequently, the V-4 lapped Monza at 124.2 mph, a lap record that stood until 1954.  

Alfa Romeo attempted a similar idea with the 1935 Bimotore that was built by engineer Luigi Bazzi at the direction of Enzo Ferrari, who was running the Alfa Romeo race team at the time. Rather than the approach of Maserati where both engines were in the front, the Bimotore had one supercharged 3.2L V8 up front, and another in the rear. Ferrari did race it a few times, but the heavy, imbalanced car consumed tires and fuel at an alarming rate that prevented its success, even at the hands of the great Tazio Nuvolari.

1936 Auto Union Type C with B. Rossmeyer

The Bimotore was built in response to the first, purpose-built supercharged V16-powered Grand Prix car, the mighty mid-engined Auto Union. Appearing in 1934, the first three versions, Types A, B, and C, all used V16s of various sizes and outputs. Their unique design stood out, as did their performance. The crowning year was 1936 when the Type C, which produced more than 500 hp, took Bernd Rosemeyer to three victories. To this day, the Auto Union is the most successful V16-powered car in history.

Shortly before WWII broke out, Alfa Romeo made a last-ditch effort to keep up with their German counterparts. The result was the Tipo 316 that raced in 1938-39. The V16 was designed by future-Ferrari designer Gioacchino Colombo and used a Roots-supercharged V16 engine that produced 350 hp. The 316 was competitive but never won a race before the war.

Coventry-Climax FWMW flat 16

Post-War Motorsports Experiments

Following WWII, the 16-cylinder engine re-emerged in 1950. BRM launched its ambitious H16 1.5-liter supercharged engine (previously covered in The Icarus Engine), which could never outrun the unreliability caused by its complexity. It was the most powerful engine of its day producing 600 hp at a shrieking 12,000 rpm. However, it rarely finished and ultimately was a failed experiment that tells the tale of the 16-cylinder engines: tremendous possibility undone by fragility and complexity.

British hubris being what it was, another attempt was made in the 1960s to crack the V16 code. Coventry-Climax's engines dominated the early 60s when they powered the first generation of mid-engined F1 cars, including two Drivers’ Championships with Jim Clarke and Constructors’ Championships for Lotus in 1963 and 1965. The company's FWMW flat 16-cylinder was developed in 1965. The FWMW could rev past 12,000 rpm and be designed like four 4-cylinder engines stitched together. It took some time to get it on the dyno as the FWMW engine had frequent failures. When it finally did make it, the output was only 209 hp, less than the preceding V8, so further development was scrapped. 

The last attempt for a racing 16-cylinder was from Porsche to compete in the Can-Am Series. This series was no holds barred, and the Porsche 917 flat 12-cylinder engine was not holding its own against souped-up American V8s. As a result, Porsche opted to add four more cylinders.

The 7.2-liter flat 16 cranked out 880 hp, despite being normally aspirated. Porsche tested the 917 with this engine and was actually reliable and fast. However, after careful analysis, they decided to go with a V12 turbocharged engine instead which could turn out 900 hp. 

1991 Cizeta V16T

Return of the Road Cars

Several attempts were made to introduce V16s into road cars in the 1980s. In 1988, BMW tested the 767iL Goldfisch, followed by Mercedes-Benz the following year with the 800 SEL. Neither model saw the light of day. 

During the supercar heyday of the 1990s, Claudio Zampolli started Cizeta (named after the phonetic spelling of his initials "C.Z." in Italian). He designed a car to outdo a Lamborghini, a company for which he was a test driver and mechanic for 25 years. The Cizeta V16T’s V16 had 6.0 liters with 64 valves and produced 540 hp. Marcello Gandini, who had designed the Countach, also designed the Cizeta V16T. The business never took off, but a number of them were made.

Undoubtedly, the most important 16-cylinder car is the Bugatti Veyron, and its successor is the Chiron. The Veyron is powered by a W16 engine that has a displacement of 8 liters and uses four turbochargers. The production engine was rated at more than 1,000 hp. In 2005, it was clocked at 253.8 mph and later upped that record to 267.8 mph in 2010.  Both runs took the title of the fastest production car at the time. The Chiron went even further when it broke the 300 mph barrier at 304.7 mph in 2019. 

The allure of the 16-cylinder engine has led many to attempt to make it a worthy powerplant, both on the track and on the road. Only recently would it be possible to say that there was a viable 16-cylinder with the ultra-rare offerings from Bugatti.

The reality is that the additional complexity and mechanical loss meant that it performed no better than a V8, V10, or V12, and introduced a whole new set of problems. In the end, those diminishing returns showed that more isn’t always better when it comes to the number of cylinders and banished the concept, never to earn mainstream acceptance.

2006 Bugatti Veyron 16.4


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