(This diary is being done at the request of Defluxion10)
The V-8 engine is, or was, a staple of American cars, powering most of Detroit’s output until the late 70s. Even today, the burble of a Mustang or Corvette is one of the most beautiful sounds out there. But in another time, the V8 was considered uncouth. If you had lots of money in the 20s or 30s, your car was powered by an inline-8.
First, an engineering lesson. A V8 is essentially 2 inline 4s sharing a crankshaft. The problem is that it is not inherently balanced and in its simplest form produces lots of vibration.
An Inline-8 however suffers from no such problems. With each combustion being symmetrical, the engine is smooth and refined.
Although there were prototype Straight 8s going back to 1903, the first was the Isotta-Fraschini Tipo 8 in 1919. The overhead valve 5.9 liter produced all of 80 horsepower. And the Tipo 8 set the standard for luxury cars through the roaring 20s and the Depression.
Duesenberg was the most luxurious American automaker. In 1921, they unveiled a 4.3 liter Straight 8, upsized to 6.9 liters in 1928, and it would last until the company’s bankruptcy in 1937.
Duesenberg was owned by Cord, which also owned Auburn. The Auburn speedster was one of the most glamorous cars of the 1930s, its engine was also a straight 8, making 150 horsepower.
Stutz also used a straight 8 for their Bearcat.
Then there was the most luxurious car of all, the Bugatti Royale. Launched on the eve of the Great Depression, only 7 were built and only 3 were sold. The engine, under the very long hood, was 12.7 liters.
All of the automakers discussed so far are no longer with us (today’s Bugatti has nothing in common with the one that built the Royale). But there is one exception. Mercedes built inline 8 aircraft engines during World War I, before any had been put in cars, and this was before they merged with Benz in 1926. They then put straight 8s under the long hoods of its most luxurious models in the 1930s including the ones that carried around Nazi top brass.
But there was a fundamental problem with the straight 8. The crankshaft had to be very long, and the flex from the centrifugal force could cause the connecting rods to rub against the cylinder walls, which was very, very bad. Also, it required a very long hood as you can see from the photos above.
Also, V8 engines began to improve. The cross-plane crank was invented in the 1920s. This spaced out firings at 90 degree intervals instead of 180 on the old flat plane cranks. This meant that combustion was balanced out between each cylinder bank and the engine was smooth, greatly reducing the straight-8’s biggest selling point. This was more complex than a straight 8 but as machining methods improved, the cost gap closed and the V8 didn’t suffer from crankshaft whip and took up much less space.
Cadillac was the first to use the cross plane V8 in 1923. By 1940, Cadillac was dominant in the luxury car field and so through sheer market share, the V8 was now the dominant engine. And consumer tastes had changed. In the 1930s, a super long hood was a status symbol, but after the war ended, they were just a nuisance. The aforementioned Cord didn’t even put a straight 8 in their famous front drive 812.
Packard was one of the last 2 major automakers to use a straight 8 in production models, surviving through 1954. But in 1955, even they gave in and offered a V8. But even that didn’t save them from going out of production in 1956.
Pontiac was the other, also phasing it out after 1954.
In 1995, Chrysler showed a concept car called the Atlantic. It was inspired by the luxury cars of the 30s and was powered by a 4 liter straight 8.
So that’s the straight 8, an interwar automotive fad that powered some of the most luxurious and elegant cars of the period but was made obsolete after World War II.