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The V8 is a very common configuration for large automobile engines. V8 engines are rarely less than 3 litres in displacement and in automobile use have gone up to 8.5 litres or so. American cars until the mid 1970s almost universally had V8 engines, and many still insist on them.

The V8 is probably the most common engine configuration in the higest echelons of motorsport, especially in the USA where it is required in IRL, ChampCar and NASCAR.

Vee angles

The most-common Vee angle for a V8 by far is 90°. This configuration produces a wide, low engine with optimal firing and vibration characteristics. Since many V6 engines are derived from V8 designs, they often use the 90° angle as well.

However, some V8s use different angles. One notable example is the Ford/Yamaha V8 used in the Ford Taurus SHO. It was based on Ford's Duratec V6 and shares that engine's 60° vee angle. This engine will be used by Volvo Cars in 2005.

Cross-plane and flat-plane

There are two classic types of V8s which differ by crankshaft:

The cross-plane V8 is the typical V8 configuration used in American road cars. Each crank pin (of four) is at a 90° angle from the previous, so that viewed from the end the crankshaft forms a cross. The cross-plane can achieve very good balance but requires heavy counterweights on the crankshaft. This makes the cross-plane V8 a slow-revving engine that cannot speed up or slow down very quickly compared to other designs, because of the greater rotating mass. While the firing of the cross-plane V8 is regular overall, the firing of each bank is not; this leads to the need to connect exhaust pipes between the two banks to design an optimal exhaust system. This complex and encumbering exhaust system has been a major problem for single-seater racing car designers.

The flat-plane V8 design has crank pins at 180°. They are imperfectly balanced and thus produce severe vibrations unless balance shafts are used. As they don't require counterweights, the crankshaft has less mass and thus inertia, allowing higher RPM and quicker acceleration. The design was introduced in racing with the Coventry Climax 1.5 L V8 which evolved from a cross-plane to a flat-plane configuration. Flat-plane V8s on road cars come from Ferrari, Lotus' Esprit V8, and TVR's Cerbera Speed Eight. This design is popular in racing engines, the most famous example being the Ford-Cosworth DFV.

More information is available here http://autozine.kyul.net/technical_school/engine/smooth4.htm .

American V8 Engines

The United States can be considered the 'home of the V8' - it has always been more popular there than anywhere else, and it is certainly even now the preferred arrangement for any large engine. With the recent exceptions of the Dodge Viper's V10 and the Ford large truck engine of the same arrangement, there are practically no large engines in the US of post-World War II design that have not been of this type.

Ford were the first company to use V8s en masse - instead of going to a six-cylinder engine like its competitors when something larger than a straight-4 was needed, Ford went straight to the V8 with its famous Ford Flathead V8 of 1932. This engine powered almost all larger Ford cars until 1953, and was produced until around 1970 by Ford licensees around the world, mostly powering commercial vehicles.

Some other companies followed Ford and built V8s, while others, like Buick, used straight-8 engines for their larger cars, and straight-6 engines for smaller ones. Postwar, increasing vehicle size meant that the straight-6 became increasingly underpowered, while the straight-8 was simply too long. This meant that by the 1950s, all American automobile manufacturers had a V8 in their range, powering the majority of the vehicles sold.

A full history of each manufacturer's engines is out of scope in this article, but engine sizes on full-size cars grew throughout the 1950s, 1960s and into the early to mid 1970s. The increasing size of full-size cars meant that smaller models of car were introduced and became more popular, with the result that by the 1960s most manufacturers had two V8 models.

The larger engines, known as big-block V8s, were used in the full-size cars. Big-blocks generally had displacements in excess of 6 litres (360 cubic inches), but in stock form are often not all that efficient. Big-blocks reached displacements of up to 8.2 litres (500 cubic inches) in production form. Once the 1970s oil crisis and pollution regulations hit, big-block V8s didn't last too much longer in cars; luxury cars lasted the longest, but by 1977 or so they were gone. In trucks and other larger vehicles, big-block V8s in their historic form lasted until the early 1990s.

Smaller engines, known as small-block V8s, were fitted in the mid-size car ranges and generally displaced between 4.4 litres (270 cubic inches) and 6 litres (360 cubic inches), though some grew as large as 6.6 litres (400 cubic inches). As can be seen, there is overlap between big-block and small-block ranges, and an engine between 6 and 6.6 litres could belong to either class. Engines like this (much evolved, of course) are still in production.

During the 1950s, 60s and 70s, every General Motors division had their own engines, whose merits varied. This enabled each division to have its own unique engine character, but made for a lot of wasted duplication of effort. Ford and Chrysler had fewer divisions, and engines tended to be shared across families a lot more.

British V8 engines

The most common British V8 is the Rover V8 , used in countless British performance cars. This is not actually a British design at all but was imported from America, its roots being in General Motors, Oldsmobile division development of a cast-aluminum block small V8 in the late 1950s. It was of the small (for the US market) size of 3.5 litres (215 cubic inches) and very light for a V8. It appeared in production in 1961 on some of that year's Buick, Oldsmobile and Pontiac models, but was soon dropped in favor of more conventional iron-blocked units.

As the aluminium block made this engine one of the lightest stock V8s built there was some attempts to use it in racing at Indianapolis. The Australian firm Repco converted this engine for Formula One by reducing it to 3 litres and fitting a single overhead camshaft per bank rather than the shared pushrod arrangement. Repco-powered Brabhams won the F1 championship twice, in 1966 and 1967.

Rover were in need of a new, more powerful engine in the mid 1960s, and became aware of this small, lightweight V8. After some negotiation they acquired rights to it and have produced it ever since, its first appearances being in Rover saloons in the late 1960s.

As well as appearing in Rover cars, the engine was widely sold to small car builders, and has appeared in all kinds of vehicles. Rover V8s feature in some models from Morgan, TVR , Triumph, Marcos, and MG, among many others. They're also the standard British engine in hot rods, much like the Chevrolet 350 small-block is to American builders.

To be done :

Aston-Martin

Rolls-Royce

French V8 engines

Simca

Czech V8 engines

Tatra used air-cooled V8 engines.

German V8 engines

Italian V8 engines

Alfa-Romeo

The Alfa-Romeo Montreal was powered by a V8.

Ferrari

Ferrari have used V8 engines in a number of cars, including the Ferrari 308 and Ferrari 328. Ferrari's smallest V8 was the turbocharged 2.0 liter found in the 1982 Ferrari 208 GTS Turbo . Five-valve versions of Ferrari's 3.5L and 3.6L V8s were found in the Ferrari 355 and Ferrari 360.

Lamborghini

Lamborghini have always fitted V12s in their top-of-the-line cars, but have built many V8s for their lower models, including the Urraco and Jalpa

Maserati

Maserati have used V8s for many of their models, including the Maserati Bora. This engine was initially designed as a racing engine for the Maserati 450S.

Spanish V8 engines

Spanish truck company Pegaso made around 100 cars in the 50s and 60s. These cars were powered by a DOHC 32 valve V8, with up to 360 hp (270 kW).

V8s in Aviation

45° Liberty engine V8. Hispano-Suiza WW1 V8.

V8s in Motorcycles

Moto-Guzzi racing V8 engine.

External links

Ford V8 Pages http://www.geocities.com/infieldg/v8main.html
Customer power: the Cosworth DFV story http://8w.forix.com/dfv.html

Categories: Piston engine configurations

Last updated: 02-08-2005 16:33:19

Last updated: 02-27-2005 18:47:33

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