Difference between revisions of "V8"

Revision as of 17:23, 15 February 2007

The Liberty V8 aircraft engine clearly shows the configuration

A V8 engine is a V engine with eight cylinders.

Overview

The V8 is a very common configuration for large automobile engines. V8 engines are rarely less than 4 litres in displacement and in automobile use have gone up to 8.5 litres or so.

The V8 is a common engine configuration in the highest echelons of motorsport, especially in the USA where it is required in IRL, ChampCar and NASCAR. Formula One will use V8 engines for the 2006 season onwards.

V angles

The most-common V 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, but with more complex cranks to even the firing cycle.

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 is used by Volvo Cars as of 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 popularized in modern 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 (the Dino), Lotus (the Esprit V8), and TVR (the Speed Eight). This design is popular in racing engines, the most famous example being the Cosworth DFV.

The cross-plane design was neither obvious nor simple to design. For this reason, most early V8 engines, including those from De Dion-Bouton, Peerless, and Cadillac, were flat-plane designs. In 1915, the cross-plane design was proposed at an automotive engineering conference in the United States, but it took another eight years to bring it to production. Cadillac and Peerless (who had hired an ex-Cadillac mathematician for the job) applied for a patent on the cross-plane design simultaneously, and the two agreed to share the idea. Cadillac introduced their "Compensated Crankshaft" V8 in 1923, with the "Equipoised Eight" from Peerless appearing in November of 1924.

More information is available here.

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 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.

Cadillac produced the first American V8 engine, 1914's L-Head. It was a complicated hand-built unit with cast iron paired closed-head cylinders bolted to an aluminum crankcase, and it used a flat-plane crankshaft. Peerless followed, introducing a V8 licensed from amusement park manufacturer, Herschell-Spillman, the next year. Cadillac and Peerless were one year apart again (1923 and 1924, respectively) with the introduction of the cross-plane crankshaft. Cunningham and Lincoln also had V8 cars in those years.

Ford were the first company to use V8s en masse. Instead of going to a straight-6 like its competitors when something larger than a straight-4 was needed, Ford designed a modern V8, the famous Flathead 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.

After World War II, greater vehicle size meant that the straight-6 became increasingly underpowered, while lower hoods and more aerodynamic styling meant that the straight-8 was simply too large. General Motors responded to Ford's V8 success with the 1949 introduction of the Oldsmobile Rocket and Cadillac OHV, the first OHV V8 engines ever produced. Chrysler introduced their FirePower hemi-head V8 the next year. Sales were beyond all expectations, so Buick, Chevrolet, and Pontiac introduced V8s of their own in 1954.

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 Chrysler, Ford, and Chevrolet 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 L (360 in³), but in stock form are often not all that efficient. Big-block displacement reached its zenith with the 1970 Cadillac Eldorado's 8.2 L (500 in³) 500. 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 L (270 in³) and 6.0 L (360 in³), though some grew as large as Ford's 6.7 L (408 in³) 400 Cleveland. As can be seen, there is overlap between big-block and small-block ranges, and an engine between 6.0 L and 6.6 L could belong to either class. Engines like this (much evolved, of course) are still in production.

During the 1950s, 1960s and 1970s, 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 much duplication of effort. Most, like the comparatively tiny Buick 215 and familiar Chevrolet 350, were confusingly shared across many divisions. Ford and Chrysler had fewer divisions, and division-specific engines were quickly abandoned in favor of a few shared designs. Today, there are less than a dozen different American V8 engines in production.

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/Buick cast-aluminum 215 V8 in 1960. It was of the small (for the US market) size of 3.5 L (215 in³) 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 was 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.

The last mass-produced car to use the Rover V8 was the Land Rover Discovery, which was replaced by an all-new model in 2005. Many independent sports cars manufacturers still use it in hand-built applications.

Triumph used the Triumph Slant-4 engine as a base of a V8 engine. The Triumph V8 was used in the Triumph Stag and in a limited number of Saab 99s.

To be done :

Aston-Martin

Rolls-Royce

French V8 engines

The French De Dion-Bouton firm was first to produce a V8 engine for sale in 1910. Later examples came from Citroën, with the never produced 1934 22CV Traction Avant, and 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 adopted the V8 configuration in racing in 1962 with the 268 SP. The first V8-powered Ferrari road car was 1974's 308 GT4, with the familiar 308 GTB following closely behind. The company continued to use this Dino V8 engine ever since with the 328, 348, and successors. Ferrari's smallest V8 (and indeed, the smallest ever) was the 2.0 L (1990 cc) unit found in the 1975 208 GT4. The company produced a slightly-larger 2.0 L V8 in the 208 GTB of the 1980s. Five-valve versions of Ferrari's 3.5 L and 3.6 L V8s were found in the Ferrari 355 and Ferrari 360. The old Dino V8 was retired for 2005 with the introduction of a shared Ferrari/Maserati V8 in the F430.

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. The company's latest V8, found in the Quattroporte, Coupe, and Spyder, is a new design shared with Ferrari.

Spanish V8 engines

Spanish truck company Pegaso made around 100 cars in the 1950s and 1960s. These cars were powered by a DOHC 32 valve V8, with up to 360 hp (270 kW).

Australian V8 engines

The V8 is a very popular engine amongst Australians, particularly the Australian country male. This popularity can be attributed to both the popularity of the V8 in the USA, but also the V8's inherent characteristics. The V8's deep growl (actually a property of the muffler system) and its powerful mid-range torque have made it a masculine engine to the more refined I6 and V6 engines. Holden (including its performance vehicle operations HDT Special Vehicles and HSV) have been manufacuring V8 performance vehicles since the late 1960's, as has Ford Australia. The performance arm of Ford Australia, Ford Performance Vehicles {FPV), have recently resurged in the market with the new Falcon BA based models.

The Australian V8 is typically a American manufactured block from either Ford or General Motors yet often use local heads and auxilary systems (pistons, exhaust etc.). However, there are a couple of exceptions to this - the Holden small block V8, and the British Leyland alloy small block V8.

The Holden small block V8 was an all Australian designed and manufactered cast-iron 90 degree pushrod OHV engine, manufactured in the capacities of 4.2L (253ci), 5.0L (308ci, later destroked to 304ci), and 5.7L (348ci, later stroked to 350ci). First introduced in 1969, finally ceasing production in 1999, it powered a variety of Holden vehicles including the Kingswood, Monaro, Torana and Commodore, and proved to be a popular and successful powerplant in Australian motorsport (especially Touring cars).

The British Leyland small block V8 was also a pushrod OHV engine, however it was an all alloy block like the British Rover V8. Unlike the Rover V8, the British Leyland V8 had a 60 degree bank and a capacity of 4.4L. The motor was originally designed and fitted to the Leyland P76 sedan, although due to its light weight and narrow bank, has been used by some street machiners in vehicles that would normally be powered by I4 powerplants.

V8s in Aviation

45° Liberty engine V8.

Hispano-Suiza WW1 V8.

V8s in Motorcycles

Moto-Guzzi racing V8 engine.

External links

Piston engine configurations
Straight	Single, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14
V	2, 4, 5, 6, 8, 10, 12, 16, 20, 24
Flat	2, 4, 6, 8, 10, 12, 16, H
W	8, 9, 12, 16, 18
Other inline	H, VR, Opposed, U (Square), X
Other	Hemi, Radial, Rotary, Pistonless, Deltic, (Wankel)

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-:''This page is about the engine configuration.  For other uses of "V8", see [[V8 (disambiguation)]]''
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+[[Image:Aero4G11.jpg|thumb|250px|The Liberty V8 aircraft engine clearly shows the configuration]]
-[[Image:Aero4G11.jpg|thumb|The Liberty V8 aircraft engine clearly shows the configuration]]
 A '''V8''' engine is a [[V engine]] with eight [[cylinder]]s.
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 * [http://www.geocities.com/infieldg/v8main.html Ford V8 Pages]
 * [http://8w.forix.com/dfv.html Customer power: the Cosworth DFV story]
+{{Piston engine configurations}}
 [[Category:Piston engine configurations]]
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