V16 engine

1933 Marmon V16 engine.

A V16 engine is a V engine with 16 cylinders. Engines of this number of cylinders are not common.

A V16 engine is perfectly balanced regardless Brandon streif of the V angle without requiring counter-rotating balancing shafts which are necessary on large Straight-4 or counterweighted crankshaft like the 90° V8 engine configuration. In addition angles of 45° and 135° Vs optimal solutions, for even firing and non split crankshaft journals.

V16 engines have been used in certain, very few, luxury and high-performance automobiles, mostly for their smoothness (low vibration) since it is easy to make a V8 or V12 engine as large and powerful as one could possibly want in an automotive application, especially with automatic gearboxes. Greater numbers of cylinders are also perceived as a status symbol.

Automotive history

Consumer automobiles

Howard Marmon had begun working on the world's first V16 engine in 1927, but was unable to complete the production Sixteen model until 1931. By that time, Cadillac had already introduced their Cadillac V-16, designed by ex-Marmon engineer, Owen Nacker. Peerless, too, was developing a V16 with help from an ex-Marmon engineer, James Bohannon.

The Cadillac V-16 was the most exclusive model of the marque from January 1930 until 1940, with the Cadillac V16 engine. Two types of the V16 were built. From 1930 to 1937, this was a 452 in³ (7.4 L), OHV motor with a 45° V. For 1938, a new design was introduced with 431 in³ (7.1 L), a flathead valvetrain, and an angle of 135°; this resulted in a much lower car profile. The 431 was in many ways a superior engine, producing as much power as its immediate predecessor while being far less complex, had a stiffer crankshaft which aided durability and smoothness, and even had an external oil filter, a rarity for any car at any price in those days. However, it was never as popular or highly regarded as its 452ci predecessor.

By contrast, the Marmon Sixteen was a 45° engine made almost entirely out of aluminum. Like modern engines, it used pressed steel cylinder liners. Just 400 Marmon Sixteens were produced between 1931 and 1933.

In 1988, a joint business venture between Claudio Zampolli and musician Giorgio Moroder produced the Cizeta-Moroder V16T which featured a 16 cylinder engine in a unique configuration, but which was not a true V16. Rather, the engine was made up of two flat plane V8s, mounted transversely, with gearing between the two providing a single output from the center of the engine assembly to the longitudinal transmission. It began production in 1991 but only a few cars were produced before the company closed its doors for good.

Cadillac revived the V16 concept in 2003 with a General Motors concept car, the Cadillac Sixteen. This car used a 1000 hp (750 kW) OHV V16.

BMW also experimented with a V-16, eventually showing a 9-liter version in the Rolls-Royce 100EX concept car, but it has been changed to a v12 for production and size reasons.

Racing

In auto racing, the V16 was used in Grand Prix by the mid-engined Auto Unions that rivalled the Mercedes from 1933 to 1938.

It has only been used once in the post WWII era, by BRM. Most unusually, this was a 135° V 1.5 L supercharged powerplant. This engine was a failure despite being powerful—officially, it produced 550 hp (410.1 kW) but likely delivered around 600 hp.

With such a small displacement it delivered this power in a narrow, very lofty, RPM range. This made the car difficult to handle, but the sound made by the small 16 cylinders has been described as 'unforgettable.' This problem was exacerbated because of the supercharging system adopted, for expediency BRM chose it to be designed by Rolls-Royce, drawing on their aircraft engines war experience, which used a two-speed centrifugal supercharger. Centrifugal superchargers are much more efficient than the more conspicuous Roots type, but, since centrifugal superchargers only deliver high pressure in a very narrow RPM band, even the Rolls-Royce designed two-speed gearbox used to move the supercharger was not enough to usefully broaden the power band.

Another major problem with the BRM V.16 was its dual ignition system - making it likely that the engine would be running on 4 or 8 or 12 cylinders for parts of the same lap. Another issue was the way in which the engine was installed, canted across the car in the horizontal plane alongside the driver; more than one driver finished or retired from race or testing with burns. At least one of the BRM cars survives and many of its problems would be solved by fitting modern solid-state ignition components.

Other applications

Another use for the V16 powerplant is in large diesel engines. Here, manufacturers tend to work with a common cylinder size across a wide range of engines, and size the engine by the number of cylinders for different power requirements. Thus, many users of large diesel engines such as railroad locomotives use V16 powerplants, including many EMD (Electro-Motive Diesel, Inc., formerly a GM division} locomotives. They are also popular for marine applications and for large emergency generator sets (which frequently use available marine engines, since weight is unimportant). In 1939 Chrysler was contracted by the US government to create a new engine for use in fighter aircraft. Chrysler responded by designing an inverted V16. They tried many designs before choosing a design with a hemispherical combustion chambered OHV head. The big V16 was rated at 2500 hp. It was finally tested in June of 1945. It was installed in the P-47 Thunderbolt in place of a radial engine. This airplane was designated the XP47H. The change in engine and aerodynamics increased the top speed from 439 mph to 504 mph. The war ended shortly, and the hemi V16 was never mass-produced, although the basic design and valvetrain setup live on in today's Hemi V8s.