Straight-8
Encyclopedia
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
with all eight cylinders
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
mounted in a straight line along the crankcase
Crankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...
. The type has been produced in side valve, overhead valve
Overhead valve
An overhead valve engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block , and uses pushrods or rods to actuate rocker arms above the cylinder...
, sleeve valve
Sleeve valve
The sleeve valve is a type of valve mechanism for piston engines, distinct from the usual poppet valve. Sleeve-valve engines saw use in a number of pre-World War II luxury cars and in USA in the Willys-Knight car and light truck...
and overhead cam configurations.
A straight-8 can be timed for inherent primary and secondary balance, with no unbalanced primary or secondary forces or moments. However, crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
torsional vibration
Torsional vibration
Torsional vibration is angular vibration of an object—commonly a shaft along its axis of rotation. Torsional vibration is often a concern in power transmission systems using rotating shafts or couplings where it can cause failures if not controlled....
, present to some degree in all engines, is sufficient to require the use of a harmonic damper
Harmonic damper
A harmonic damper is a device fitted to the free end of the crankshaft of an internal combustion engine. It is essential in engines with long crankshafts and is present on most engines as it reduces torsional vibrations that tend to peak at certain speeds.-Need:Without the presence of a damper a...
at the accessory end of the crankshaft. Without such damping, fatigue cracking
Fatigue (material)
'In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.Fatigue occurs...
near the rear main bearing
Main bearing
In a piston engine, the main bearings are the bearings on which the crankshaft rotates, usually plain or journal bearings.All engines have a minimum of two main bearings, one at each end of the crankshaft, and they may have as many as one more than the number of crank pins...
journal may occur, leading to engine failure.
Although an inline six cylinder engine can also be timed for inherent primary and secondary balance, a straight-8 develops more power strokes per revolution and, as a result, will run more smoothly under load than an inline six. Also, due to the even number of power strokes per revolution, the straight-8 does not produce unpleasant odd-order harmonic vibration in the vehicle's driveline at low engine speeds.
The smooth running characteristics of the straight-8 made it popular in luxury and racing cars of the past. However, the engine's length demanded the use of a long engine compartment, making the basic design unacceptable in modern vehicles. Also, due to the length of the engine, torsional vibration in both crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
and camshaft
Camshaft
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.-History:An early cam was built into Hellenistic water-driven automata from the 3rd century BC. The camshaft was later described in Iraq by Al-Jazari in 1206. He employed it as part of his automata,...
can adversely affect reliability and performance at high speeds. In particular, a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force
Centrifugal force
Centrifugal force can generally be any force directed outward relative to some origin. More particularly, in classical mechanics, the centrifugal force is an outward force which arises when describing the motion of objects in a rotating reference frame...
on the crank throws at high engine rpm, could cause physical contact between the connecting rod
Connecting rod
In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion....
s and crankcase
Crankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...
walls, leading to the engine's destruction. As a result, the design has been displaced almost completely by the shorter and sturdier V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....
configuration.
Early period (1903-1918)
The first straight-eight was conceived by Charron, Girardot et VoigtCharron, Girardot et Voigt
Charron, Girardot et Voight was a French racing team that opened one of the first French car dealerships.The dealership opened in 1897, on Avenue de la Grande Armée in Paris. CGV showed their first car in 1901. In 1904, they produced 216 cars with 4 cylinder engines, which sold for up to £1200 in...
(CGV) in 1903, but never built. Great strides were made during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, as Mercedes
Mercedes (car)
Mercedes was a brand of the Daimler-Motoren-Gesellschaft . DMG which began to develop in 1900, after the death of its co-founder, Gottlieb Daimler...
made straight-eight aircraft engines. Advantages of the straight-8 engine for aircraft applications included the aerodynamic
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
efficiency of the long, narrow configuration, and the inherent balance of the engine making counterweights on the crankshaft unnecessary. The disadvantages of crank and camshaft twisting were not considered at this time, since aircraft engines of the time ran at low speeds to keep propeller tip speed below the speed of sound.
Unlike the V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....
configuration, examples of which were used in De Dion-Bouton
De Dion-Bouton
De Dion-Bouton was a French automobile manufacturer and railcar manufacturer operating from 1883 to 1932. The company was founded by the Marquis Jules-Albert de Dion, Georges Bouton and his brother-in-law Charles Trépardoux....
, Scripps-Booth
Bi-Autogo (automobile)
The Bi-Autogo was a prototype American motorcycle, built in 1913.Designed and built by Detroit artist & engineer James Scripps Booth, it had the usual two wheels , plus two pairs of smaller, retractable outrigger wheels in the three-seater body...
, and Cadillac
Cadillac V8 engine
Cadillac was the first automobile maker to mass produce a V8 engine. The company has produced eight generations of V8s since 1914, and was the last General Motors division to retain its own V8 design.-L-Head:...
automobiles by 1914, no straight-8 engines were used in production cars before 1920.
Luxury automobiles
Italy's Isotta-FraschiniIsotta-Fraschini
Isotta Fraschini represents two Italian manufacturing companies which produce, respectively, marine engines and luxury goods. In the early 20th century it was famous worldwide as a luxury car manufacturer.-History:...
introduced the first production automobile straight-eight in their Tipo 8 at the Paris Salon in 1919 and began delivery in 1920. Leyland Motors introduced their OHC
Overhead camshaft
Overhead cam valvetrain configurations place the engine camshaft within the cylinder heads, above the combustion chambers, and drive the valves or lifters in a more direct manner compared to overhead valves and pushrods...
straight-8 powered Leyland Eight
Leyland Eight
The Leyland Eight was a luxury car produced by Leyland Motors from 1920 to 1923. The car was designed by the chief engineer of Leyland Motors, J.G. Parry-Thomas and his assistant Reid Railton, and was intended to be the finest car available...
luxury car at the International Motor Exhibition
British International Motor Show
The British International Motor Show is an automobile show held biennially in the United Kingdom. It is recognised as an international show by the Organisation Internationale des Constructeurs d'Automobiles. The 2008 was the last event with no news of a return of the British International Motor Show...
at Olympia, London
Olympia, London
Olympia is an exhibition centre and conference centre in West Kensington, on the boundary between The Royal Borough of Kensington & Chelsea and Hammersmith & Fulham, London, W14 8UX, England. It opened in the 19th century and was originally known as the National Agricultural Hall.Opened in 1886,...
in 1920. The Duesenberg
Duesenberg
Duesenberg was an Auburn, Indiana based American luxury automobile company active in various forms from 1913 to 1937, most famous for its high-quality passenger cars and record-breaking racing cars.-History:...
brothers introduced their first production straight-eight in 1921.
Straight-8 engines were used in expensive luxury and performance vehicles until after World War II. Bugatti
Bugatti
Automobiles E. Bugatti was a French car manufacturer founded in 1909 in Molsheim, Alsace, as a manufacturer of high-performance automobiles by Italian-born Ettore Bugatti....
s and Duesenberg
Duesenberg
Duesenberg was an Auburn, Indiana based American luxury automobile company active in various forms from 1913 to 1937, most famous for its high-quality passenger cars and record-breaking racing cars.-History:...
s commonly used double overhead cam straight-8 engines. Other notable straight-8-powered automobiles were built by Mercedes-Benz
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
, Isotta-Fraschini
Isotta-Fraschini
Isotta Fraschini represents two Italian manufacturing companies which produce, respectively, marine engines and luxury goods. In the early 20th century it was famous worldwide as a luxury car manufacturer.-History:...
, Alfa Romeo
Alfa Romeo
Alfa Romeo Automobiles S.p.A. is an Italian manufacturer of cars. Founded as A.L.F.A. on June 24, 1910, in Milan, the company has been involved in car racing since 1911, and has a reputation for building expensive sports cars...
, Stutz
Stutz Motor Company
The Stutz Motor Company was a producer of luxury cars based in Indianapolis, Indiana, USA. Production began in 1911 and continued through 1935. The marque reappeared in 1968 under the aegis of Stutz Motor Car of America, Inc., and with a newly defined modern retro-look. Although the company is...
, Stearns-Knight
Stearns-Knight
Stearns-Knight was a luxury automobile produced in Cleveland, Ohio first by the F.B. Stearns Company from 1900 to 1925, and then under ownership by WillysOverland Company of Toledo, Ohio until 1929....
and Packard
Packard
Packard was an American luxury-type automobile marque built by the Packard Motor Car Company of Detroit, Michigan, and later by the Studebaker-Packard Corporation of South Bend, Indiana...
. One marketing feature of these engines was their impressive length — some of the Duesenberg engines were over 4 ft (1.2 m) long, resulting in the long hood (bonnet) found on these automobiles.
Premium automobiles in the United States
In the United States in the 1920s, automobile manufacturers, including ChandlerChandler Motor Car
The Chandler Motor Company produced automobiles in the United States of America during the 1910s and 1920s.-Corporate strategy:It was incorporated in 1913, with Frederick C. Chandler as President, headquartered and with its factory in Cleveland, Ohio. Chandler was a former designer for the Lozier...
, Gardner
Gardner (automobile)
Gardner was an automobile maker based in St. Louis Missouri between 1920 and 1931.Without a dollar in his pocket, Russell E. Gardner left his home state Tennessee for St. Louis in 1879. Three-and-a-half decades later he was a millionaire several times over. Russell Gardner had made it big in St...
, and Auburn
Auburn Automobile
Auburn was a brand name of American automobiles produced from 1900 through 1936.-Corporate history:The Auburn Automobile Company grew out of the Eckhart Carriage Company, founded in Auburn, Indiana, in 1875 by Charles Eckhart...
, began using straight-eight engines in cars targeted at the middle class. Engine manufacturer Lycoming
Lycoming Engines
Lycoming Engines is a U.S. aircraft engine company, known primarily for its general aviation engines. For most of its history Lycoming has been part of the AVCO group as AVCO Lycoming. In 1987 AVCO was purchased by Textron to become Textron Lycoming...
built straight-eight engines for sale to automobile manufacturers, including Gardner, Auburn, and Locomobile
Locomobile
The Locomobile Company of America was an automobile manufacturer founded in 1899. For the first two years it was located in Watertown, Massachusetts, but production was transferred to Bridgeport, Connecticut during 1900 where it remained until the company's demise in 1929...
. Lycoming was purchased by Auburn owner Errett Lobban Cord
Errett Lobban Cord
Errett Lobban "E. L." Cord was a leader in United States transport during the early and middle 20th century.Cord founded the Cord Corporation in 1929 as a holding company for over 150 companies he controlled, mostly in the field of transportation...
, who used a Lycoming straight-eight in his front-drive Cord L-29 automobile, and had Lycoming build the straight-eight engine for the Duesenberg Model J, which had been designed by the Duesenberg brothers for the Cord-owned Duesenberg Inc. The automobile manufacturers within the Cord Corporation, comprising Auburn, Cord, and Duesenberg, were shut down in 1937. Lycoming continued afterward as an aircraft engine manufacturer.
In the late Twenties, volume sellers Hudson and Studebaker
Studebaker
Studebaker Corporation was a United States wagon and automobile manufacturer based in South Bend, Indiana. Founded in 1852 and incorporated in 1868 under the name of the Studebaker Brothers Manufacturing Company, the company was originally a producer of wagons for farmers, miners, and the...
introduced straight-8 engines for the premium vehicles in their respective lines. They were followed in the early 1930s by Nash (with a dual-ignition unit), REO
REO Motor Car Company
The REO Motor Car Company was a Lansing, Michigan based company that produced automobiles and trucks from 1905 to 1975. At one point the company also manufactured buses on its truck platforms.REO was initiated by Ransom E. Olds during August 1904...
and the Buick
Buick
Buick is a premium brand of General Motors . Buick models are sold in the United States, Canada, Mexico, China, Taiwan, and Israel, with China being its largest market. Buick holds the distinction as the oldest active American make...
, Oldsmobile
Oldsmobile
Oldsmobile was a brand of American automobile produced for most of its existence by General Motors. It was founded by Ransom E. Olds in 1897. In its 107-year history, it produced 35.2 million cars, including at least 14 million built at its Lansing, Michigan factory...
and Pontiac
Pontiac
Pontiac was an automobile brand that was established in 1926 as a companion make for General Motors' Oakland. Quickly overtaking its parent in popularity, it supplanted the Oakland brand entirely by 1933 and, for most of its life, became a companion make for Chevrolet. Pontiac was sold in the...
divisions of General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...
.
The Buick straight-8 engine
Buick Straight-8 engine
The Buick Straight-8 engine was produced from 1931 to 1953 and sold in Buick automobiles. Like many American automobile makers, Buick adopted the straight-8 engine in 1931 as a more powerful alternative to the previous inline-6 engines...
was an overhead valve
Overhead valve
An overhead valve engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block , and uses pushrods or rods to actuate rocker arms above the cylinder...
design, while the Oldsmobile
Oldsmobile Straight-8 engine
Oldsmobile produced a "multicylinder" straight-8 engine in the 1930s. This was the company's top engine choice from 1937 until the 1949 introduction of the Rocket V8.-257:...
and Pontiac
Pontiac Straight-8 engine
The straight-8 was an eight-cylinder, in-line automobile engine that was used in production Pontiacs from 1933 to 1954. Introduced in the fall of 1932 for the 1933 models, it was Pontiac's most powerful engine at the time and was the least expensive eight-cylinder engine built by an American...
straight-8s were flathead
Flathead
Flathead may refer to:* Flat-head screwdriver, a screwdriver designed to turn slotted screws* Flat-head screw, a screw with a flat top, designed to be installed in a countersunk hole* Flathead engine, a valve configuration...
engines. Chevrolet, as an entry-level marque, did not have a straight-8. Cadillac, the luxury brand of General Motors, stayed with their traditional V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....
s. In order to have engines as smooth as the straight-8s of its competitors, Cadillac introduced the crossplane
Crossplane
The crossplane or cross-plane is a crankshaft design for V8 engines with a 90° angle between the cylinder banks.The crossplane crankshaft has four crankpins, each offset at 90° from the adjacent crankpins...
crankshaft for its V8
Cadillac V8 engine
Cadillac was the first automobile maker to mass produce a V8 engine. The company has produced eight generations of V8s since 1914, and was the last General Motors division to retain its own V8 design.-L-Head:...
, and added V12
V12 engine
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
and V16 engine
V16 engine
A V16 engine is a V engine with 16 cylinders. Engines of this number of cylinders are uncommon in automotive use.A V16 engine is perfectly balanced regardless of the V angle without requiring counter-rotating balancing shafts which are necessary to balance Straight-4 and odd number of cylinder...
s to the top of its lineup.
Ford
Ford Motor Company
Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...
never adopted the straight-8, using V8 engines in their entry-level cars and V8 or V12 engines in their Lincoln
Lincoln (automobile)
Lincoln is an American luxury vehicle brand of the Ford Motor Company. Lincoln vehicles are sold mostly in North America.-History:The company was founded in August 1915 by Henry M. Leland, one of the founders of Cadillac . During World War I, he left Cadillac which was sold to General Motors...
luxury cars from the 1930s on. Chrysler
Chrysler
Chrysler Group LLC is a multinational automaker headquartered in Auburn Hills, Michigan, USA. Chrysler was first organized as the Chrysler Corporation in 1925....
used a flathead straight-8 in its premium Chrysler, Dodge
Dodge
Dodge is a United States-based brand of automobiles, minivans, and sport utility vehicles, manufactured and marketed by Chrysler Group LLC in more than 60 different countries and territories worldwide....
and DeSoto
DeSoto (automobile)
The DeSoto was a brand of automobile based in the United States, manufactured and marketed by the Chrysler Corporation from 1928 to 1961. The DeSoto logo featured a stylized image of Hernando de Soto...
cars, including the Imperial luxury model.
Airships
The British R101R101
R101 was one of a pair of British rigid airship completed in 1929 as part of a British government programme to develop civil airships capable of service on long-distance routes within the British Empire. It was designed and built by an Air Ministry-appointed team and was effectively in competition...
rigid airship
Airship
An airship or dirigible is a type of aerostat or "lighter-than-air aircraft" that can be steered and propelled through the air using rudders and propellers or other thrust mechanisms...
was fitted with five Beardmore Tornado
Beardmore Tornado
-Further reading:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Gunston, Bill. Development of Piston Aero Engines. Cambridge, England. Patrick Stephens Limited, 2006. ISBN 0-7509-4478-1* Lumsden, Alec. British Piston...
Mk I inline 8 cylinder diesel engines. These engines were intended to give an output of 700 bhp at 1,000 rpm but in practice had a continuous output rating of only 585 bhp at 900 rpm.
Post-war
After World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, changes in the automobile market resulted in the decline and final extinction of the straight-8 as an automobile engine. The primary users of the straight-8 were American luxury and premium cars that were carried over from before the war. A Flxible
Flxible
The Flxible Co. was a motorcycle sidecar, funeral car, ambulance, intercity coach and transit bus manufacturing company based in the United States that was founded in 1913, and which closed in 1996.-History:In 1913, Hugo H. Young and Carl F...
inter-city bus used the Buick straight-8.
During World War II, improvements in the refinery technology used to produce aviation gasoline resulted in the availability of large amounts of inexpensive high octane
Octane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
gasoline. Engines could be designed with higher compression ratios to take advantage of high-octane gasoline. This led to more highly stressed engines which amplified the limitations of the long crankshaft and camshaft in the straight-8 engines.
Oldsmobile replaced their straight-8 with a V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....
in 1949, at which time Cadillac also introduced their first overhead valve V8. Chrysler replaced its straight-8 with its famous Hemi
Chrysler Hemi engine
The Chrysler Hemi engine, known by the trademark Hemi, is a series of V8 engines built by Chrysler with a hemispherical combustion chamber. Three different types of Hemi engines have been built by Chrysler for automobiles: the first from 1951–1958, the second from 1964–1971, and the third...
V-8 for 1951. Hudson retired its straight-8 at the end of the 1952 model year. Buick introduced a 322 in³ (5.3 L) V8 in 1953, which coincidentally had the same displacement as their straight-8, the latter being produced until the end of the 1953 model year. Pontiac maintained production on their straight-8, as well as a L-head inline six, through the end of the 1954 model year, after which a V8 became standard. Packard ended production of their signature straight-8 at the end of 1954, replacing it with an overhead valve V8.
By the end of the 1970s overhead valve V8s powered 80% of automobiles built in the US, and most of the rest had six cylinder engines.
In Europe, many automobile factories had been destroyed during World War II, and it took many years before war-devastated economies recovered enough to make large cars popular again. The change in the design of cars from a long engine compartment between separate fenders to the modern configuration with its shorter engine compartment quickly led to the demise of the straight-8 engine. As a result, four and six cylinder engines powered the majority of cars in Europe, and the few eight-cylinder cars produced were in the V8 configuration.
Performance and racing cars
Alfa Romeo
Alfa Romeo Automobiles S.p.A. is an Italian manufacturer of cars. Founded as A.L.F.A. on June 24, 1910, in Milan, the company has been involved in car racing since 1911, and has a reputation for building expensive sports cars...
, Mercedes-Benz
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
and Miller built successful racing cars with high-performance dual overhead camshaft straight-8 engines in the 1920s and 1930s.
The Duesenberg
Duesenberg
Duesenberg was an Auburn, Indiana based American luxury automobile company active in various forms from 1913 to 1937, most famous for its high-quality passenger cars and record-breaking racing cars.-History:...
brothers introduced the first successful straight-8 racing engine in 1920, when their 3 L engine placed third, fourth and sixth at the Indianapolis 500
Indianapolis 500
The Indianapolis 500-Mile Race, also known as the Indianapolis 500, the 500 Miles at Indianapolis, the Indy 500 or The 500, is an American automobile race, held annually, typically on the last weekend in May at the Indianapolis Motor Speedway in Speedway, Indiana...
. The following year one of their cars won the French Grand Prix
French Grand Prix
The French Grand Prix was a race held as part of Fédération Internationale de l'Automobile's annual Formula One automobile racing championships....
, while two others placed fourth and sixth in the race. Based on work the company had done on 16 cylinder aircraft engines during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, the overhead camshaft
Overhead camshaft
Overhead cam valvetrain configurations place the engine camshaft within the cylinder heads, above the combustion chambers, and drive the valves or lifters in a more direct manner compared to overhead valves and pushrods...
, three-valve-per-cylinder
Multi-valve
In automotive engineering a multi-valve or multivalve engine is one where each cylinder has more than two valves. A multi-valve engine has better breathing and can operate at higher revolutions per minute than a two-valve engine, delivering more power.- Multi-valve rationale :A multi-valve design...
engine produced 115 bhp at 4,250 rpm, and was capable of revving to an astonishing (at the time) 5,000 rpm. No Grand Prix engine before the war had peaked at more than 3,000 rpm.
Bugatti
Bugatti
Automobiles E. Bugatti was a French car manufacturer founded in 1909 in Molsheim, Alsace, as a manufacturer of high-performance automobiles by Italian-born Ettore Bugatti....
experimented with straight-8 engines from 1922, but in 1924, he introduced the 2 L Bugatti Type 35
Bugatti Type 35
The Type 35 was the most successful of the Bugatti racing models. Its version of the Bugatti arch-shaped radiator that had evolved from the more architectural one of the Bugatti Type 13 Brescia, was to become the one that the marque is most known for though even in the ranks of the various Type 35s...
, one of the most successful racing cars of all time, which eventually won over 1000 races. Like the Duesenbergs, Bugatti got his ideas from building aircraft engines during WWI, and like them, his engine was a high-revving overhead camshaft unit with three valves per cylinder. It produced 100 bhp at 5,000 rpm and could be revved to over 6,000 rpm. Nearly 400 of the Type 35 and its derivatives were produced, an all-time record for Grand Prix motor racing
Grand Prix motor racing
Grand Prix motor racing has its roots in organised automobile racing that began in France as far back as 1894. It quickly evolved from a simple road race from one town to the next, to endurance tests for car and driver...
.
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Alfa Romeo
Alfa Romeo Automobiles S.p.A. is an Italian manufacturer of cars. Founded as A.L.F.A. on June 24, 1910, in Milan, the company has been involved in car racing since 1911, and has a reputation for building expensive sports cars...
were the first to react to the engineering problems of the straight-8: in their racing car engines for the P2
Alfa Romeo P2
The Alfa Romeo P2 won the inaugural Automobile World Championship in 1925, taking victory in two of the four championship rounds when Antonio Ascari drove it in the European Grand Prix at Spa and Gastone Brilli-Peri won the Italian Grand Prix at Monza after Ascari died while leading the intervening...
and P3
Alfa Romeo P3
The Alfa Romeo P3, P3 monoposto or Tipo B was a classic Grand Prix car designed by Vittorio Jano, one of the Alfa Romeo 8C models. The P3 was first genuine single-seat Grand Prix racing car and Alfa Romeo's second monoposto after Tipo A monoposto . It was based on the earlier successful Alfa Romeo P2...
and in their Alfa Romeo 8C
Alfa Romeo 8C
-1935 Monoposto 8C 35 Type C:Eight 3.8 litre versions, sharing no castings with the earlier blocks, were individually built for racing in five months, most being used in the Alfa Romeo Monoposto 8C 35 Type C, as raced by Scuderia Ferrari. The 3.8 produced at 5500 rpm, and had from...
2300/2600/2900 sports cars of Mille Miglia
Mille Miglia
The Mille Miglia was an open-road endurance race which took place in Italy twenty-four times from 1927 to 1957 ....
and Le Mans
Le Mans
Le Mans is a city in France, located on the Sarthe River. Traditionally the capital of the province of Maine, it is now the capital of the Sarthe department and the seat of the Roman Catholic diocese of Le Mans. Le Mans is a part of the Pays de la Loire region.Its inhabitants are called Manceaux...
fame the camshaft drive had been moved to the engine centre, between cylinders #4 and 5, thus reducing the aforementioned limitations. The straight-8 was actually built as a symmetrical pair of straight-4 engines joined in the middle at common gear trains for the camshafts and superchargers. It had two overhead camshafts, but only two valves per cylinder.
The Alfa Romeo straight-8 would return after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
to dominate the first season of Formula One
Formula One
Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...
racing in 1950, and to win the second season against competition from Ferrari
Ferrari
Ferrari S.p.A. is an Italian sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari in 1929, as Scuderia Ferrari, the company sponsored drivers and manufactured race cars before moving into production of street-legal vehicles as Ferrari S.p.A. in 1947...
's V12-powered car in 1951. The Alfa Romeo 158/159 Alfetta
Alfa Romeo 158/159 Alfetta
The Alfa Romeo 158/159, also known as the Alfetta , is one of the most successful racing cars ever produced. The 158 and its derivative, the 159, took 47 wins from 54 Grands Prix entered. It was originally developed for the pre-World War II voiturette formula and has a 1.5 litre straight-8...
was originally designed in 1937 and won 47 of 54 Grands Prix entered between 1938 and 1951 (with a six-year gap in the middle caused by the war). By 1951, their 1.5 L supercharged
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
engines could produce 425 bhp at 9,300 rpm, and could rev as high as 10,500 rpm. However, the engines were at the end of their potential, and rule changes for the 1952 season made the Alfettas obsolete.
Mercedes-Benz
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
would create the last notable straight-8 racing cars in 1955, with the championship-winning W196
Mercedes-Benz W196
The Mercedes-Benz W196 was the Mercedes-Benz Formula One entry in the and Formula One seasons, winning 9 of 12 races entered in the hands of Juan Manuel Fangio and Stirling Moss....
Formula One racing car and the 300SLR sports racing car. The 300SLR was famous for Stirling Moss
Stirling Moss
Sir Stirling Craufurd Moss, OBE FIE is a former racing driver from England...
and Denis Jenkinson
Denis Jenkinson
Denis Sargent Jenkinson , Jenks or DSJ as he was known in the pages of Motor Sport, was a journalist deeply involved in motorsports...
's victory in the 1955 Mille Miglia
Mille Miglia
The Mille Miglia was an open-road endurance race which took place in Italy twenty-four times from 1927 to 1957 ....
, but notorious for Pierre Levegh
Pierre Levegh
Pierre Eugène Alfred Bouillin was a French sportsman and racing driver. He took the racing name Pierre Levegh in memory of his uncle, a pioneering driver who died in 1904...
's notorious accident
1955 Le Mans disaster
The 1955 Le Mans disaster occurred during the 1955 24 Hours of Le Mans motor race, when a crash caused large parts of racing car debris to fly into the crowd. The driver was killed, as were 83 spectators. A further 120 people were injured...
at the 1955 24 Hours of Le Mans
1955 24 Hours of Le Mans
The 1955 24 Hours of Le Mans was the 23rd Grand Prix of Endurance, and took place on June 11 and 12, 1955. It was also the fourth round of the World Sportscar Championship....
. The 300SLR was the final development of the Alfa Romeo design of the early 1930s as not only the camshaft, but now also the gearbox was driven from the engine's centre. Engineers calculated that torsional stresses would be too high if they took power from the end of the long crankshaft, so they put a central gear train in the middle (which also ran the dual camshafts, dual magnetos, and other accessories) and ran a drive shaft to the clutch housing at the rear.
Current use
Straight-8s are currently used in luxury coachesCoach (vehicle)
A coach is a large motor vehicle, a type of bus, used for conveying passengers on excursions and on longer distance express coach scheduled transport between cities - or even between countries...
, alongside V12
V12 engine
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
engines. They are generally preferred by coach drivers for their lower fuel consumption and smoother acceleration. Large eight-cylinder inline engines are also commonly used in ships.