The Offenhauser Racing Engine , or Offy , is a racing engine design that dominated American open wheel racing for more than 50 years and is still popular among vintage sprint and midget car racers.
69-451: The Offenhauser engine, familiarly known as the "Offy", was an overhead cam monoblock 4-stroke internal combustion engine developed by Fred Offenhauser and Harry Arminius Miller . Originally, it was sold as a marine engine . In 1930 a four-cylinder 151 cu in (2.47 L) Miller engine installed in a race car set a new international land speed record of 144.895 mph (233.186 km/h). Miller developed this engine into
138-406: A compressor in the turbocharger pressurises the intake air before it enters the inlet manifold . In the case of a turbocharger, the compressor is powered by the kinetic energy of the engine's exhaust gases, which is extracted by the turbocharger's turbine . The main components of the turbocharger are: The turbine section (also called the "hot side" or "exhaust side" of the turbo) is where
207-459: A 15:1 compression ratio and a 4.28125-by-4.375-inch (108.744 mm × 111.125 mm) bore and stroke could produce 420 hp (310 kW) at 6,600 rpm (1.77 hp per cubic inch, 81 kW/L) making it remarkably power-dense. Other variants of the engine produced even higher outputs of 3 hp per cubic inch (137 kW/L), unparalleled for their size and capacity in power-to cubic-inch/cylinder-count ratio. Another reason for
276-456: A DOHC configuration gradually increased after World War II, beginning with sports cars. Iconic DOHC engines of this period include the 1948–1959 Lagonda straight-six engine , the 1949–1992 Jaguar XK straight-six engine and the 1954–1994 Alfa Romeo Twin Cam inline-four engine. The 1966-2000 Fiat Twin Cam inline-four engine was one of the first DOHC engines to use a toothed timing belt instead of
345-454: A famous Formula Libre race, where Rodger Ward shocked the expensive and exotic sports car contingent by beating them on the road course in an Offenhauser powered midget car , which was normally considered competitive on oval tracks only. On the strength of this performance, the car was entered in the Formula 1 1959 US Grand Prix at Sebring, where it was totally uncompetitive, setting
414-557: A flat engine. A V engine or flat engine requires four camshafts to function as a DOHC engine, since having two camshafts in total would result in only a single camshaft per cylinder bank for these engine layouts. Some V engines with four camshafts have been marketed as "quad-cam" engines, however technically "quad-cam" would require four camshafts per cylinder bank (i.e. eight camshafts in total), therefore these engines are merely dual overhead camshaft engines. Many DOHC engines have four valves per cylinder. The camshaft usually operates
483-608: A fully enclosed-drivetrain), the American Liberty L-12 V12 engine, which closely followed the later Mercedes D.IIIa design's partly-exposed SOHC valvetrain design; and the Max Friz -designed; German BMW IIIa straight-six engine. The DOHC Napier Lion W12 engine was built in Great Britain beginning in 1918. Most of these engines used a shaft to transfer drive from the crankshaft up to the camshaft at
552-460: A lower boost threshold, and greater efficiency at higher engine speeds. The benefit of variable-geometry turbochargers is that the optimum aspect ratio at low engine speeds is very different from that at high engine speeds. An electrically-assisted turbocharger combines a traditional exhaust-powered turbine with an electric motor, in order to reduce turbo lag. This differs from an electric supercharger , which solely uses an electric motor to power
621-538: A more complete list. In the 11 World Championship years, the Meyer-Drake Offenhauser engine partnered for at least one race with the following 35 constructors : (excluding the 1950-1960 Indianapolis 500) ( key ) Overhead cam An overhead camshaft ( OHC ) engine is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber . This contrasts with earlier overhead valve engines (OHV), where
690-453: A qualifying time of 3:43.8 compared to the pole time of 3 minutes dead and being the slowest Formula 1 starter at 3:33.4. When Ford came onto the scene in 1963, with much increased competition and sanctioning body rule changes, the Offy began to lose its domination over Indy car racing, although it remained a competitive winner on the circuit including at the 500 through the mid-1970s even with
759-512: A ring of holes or circular grooves allows air to bleed around the compressor blades. Ported shroud designs can have greater resistance to compressor surge and can improve the efficiency of the compressor wheel. The center hub rotating assembly (CHRA) houses the shaft that connects the turbine to the compressor. A lighter shaft can help reduce turbo lag. The CHRA also contains a bearing to allow this shaft to rotate at high speeds with minimal friction. Some CHRAs are water-cooled and have pipes for
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#1732772475398828-415: A timing chain. In the 1980s, the need for increased performance while reducing fuel consumption and exhaust emissions saw increasing use of DOHC engines in mainstream vehicles, beginning with Japanese manufacturers. By the mid-2000s, most automotive engines used a DOHC layout. Turbocharging In an internal combustion engine , a turbocharger (also known as a turbo or a turbosupercharger )
897-637: A turbocharger was in June 1924 when the first heavy duty turbocharger, model VT402, was delivered from the Baden works of Brown, Boveri & Cie , under the supervision of Alfred Büchi, to SLM, Swiss Locomotive and Machine Works in Winterthur. This was followed very closely in 1925, when Alfred Büchi successfully installed turbochargers on ten-cylinder diesel engines, increasing the power output from 1,300 to 1,860 kilowatts (1,750 to 2,500 hp). This engine
966-458: A twin overhead cam, four-cylinder, four-valve-per-cylinder 220 cu in (3.6 L) racing engine. Variations of this design were used in midgets and sprints into the 1960s, with a choice of carburetion or Hilborn fuel injection . When both Miller and the company to whom he had sold much of the equipment and rights went bankrupt in 1933, Offenhauser opened a shop a block away and bought rights to engines, special tooling and drawings at
1035-544: A wide variety of engine displacements. Offenhauser (and Meyer-Drake, in later years) frequently made blocks, pistons, rods, and crankshafts to specific customer requests. However, certain engine sizes were common, and could be considered the "standard" Offenhauser engines: From 1950 to 1960, the Indianapolis 500 was a round of the World Drivers' Championship . See Indianapolis Motor Speedway race results for
1104-443: Is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the engine in order to produce more power for a given displacement . The current categorisation is that a turbocharger is powered by the kinetic energy of the exhaust gases, whereas a supercharger is mechanically powered (usually by a belt from the engine's crankshaft). However, up until
1173-474: Is increasing. The companies which manufacture the most turbochargers in Europe and the U.S. are Garrett Motion (formerly Honeywell), BorgWarner and Mitsubishi Turbocharger . Turbocharger failures and resultant high exhaust temperatures are among the causes of car fires. Failure of the seals will cause oil to leak into the cylinders causing blue-gray smoke. In diesel engines, this can cause an overspeed,
1242-531: Is possible. The first known automotive application of timing belts to drive overhead camshafts was the 1953 Devin-Panhard racing specials built for the SCCA H-modified racing series in the United States. These engines were based on Panhard OHV flat-twin engines, which were converted to SOHC engines using components from Norton motorcycle engines. The first production car to use a timing belt
1311-453: Is too large, the turbo will fail to create boost at low speeds; if the aspect ratio is too small, the turbo will choke the engine at high speeds, leading to high exhaust manifold pressures, high pumping losses, and ultimately lower power output. By altering the geometry of the turbine housing as the engine accelerates, the turbo's aspect ratio can be maintained at its optimum. Because of this, variable-geometry turbochargers often have reduced lag,
1380-441: Is unable to produce significant boost. At low rpm, the exhaust gas flow rate is unable to spin the turbine sufficiently. The boost threshold causes delays in the power delivery at low rpm (since the unboosted engine must accelerate the vehicle to increase the rpm above the boost threshold), while turbo lag causes delay in the power delivery at higher rpm. Some engines use multiple turbochargers, usually to reduce turbo lag, increase
1449-701: The Consolidated B-24 Liberator , Lockheed P-38 Lightning , Republic P-47 Thunderbolt and experimental variants of the Focke-Wulf Fw 190 . The first practical application for trucks was realized by Swiss truck manufacturing company Saurer in the 1930s. BXD and BZD engines were manufactured with optional turbocharging from 1931 onwards. The Swiss industry played a pioneering role with turbocharging engines as witnessed by Sulzer, Saurer and Brown, Boveri & Cie . Automobile manufacturers began research into turbocharged engines during
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#17327724753981518-551: The Duesenberg Model J , which was powered by a DOHC straight-eight engine. The 1931–1935 Stutz DV32 was another early American luxury car to use a DOHC engine. Also in the United States, the DOHC Offenhauser racing engine was introduced in 1933. This inline-four engine dominated North American open-wheel racing from 1934 until the 1970s. Other early SOHC automotive engines were the 1920–1923 Wolseley Ten ,
1587-563: The National Advisory Committee for Aeronautics (NACA) and Sanford Alexander Moss showed that a turbocharger could enable an engine to avoid any power loss (compared with the power produced at sea level) at an altitude of up to 4,250 m (13,944 ft) above sea level. The testing was conducted at Pikes Peak in the United States using the Liberty L-12 aircraft engine. The first commercial application of
1656-413: The crankshaft ) whereas a turbocharger is powered by the kinetic energy of the engine's exhaust gas . A turbocharger does not place a direct mechanical load on the engine, although turbochargers place exhaust back pressure on engines, increasing pumping losses. Supercharged engines are common in applications where throttle response is a key concern, and supercharged engines are less likely to heat soak
1725-505: The pole position in 10 of the 11 years. The Offenhauser shop began to do machine work for Lockheed in 1940, as the arms build-up for anticipated war began. The last prewar engine was shipped on July 17, 1941, and the plant began producing hydraulic systems after the Pearl Harbor attack . Leo Goossen finally became a full-time Offenhauser employee in 1944, and Fred Offenhauser sold the company in 1946. In 1959 Lime Rock Park held
1794-537: The 1903 Marr Auto Car SOHC engine built in the United States. The first DOHC engine was a Peugeot inline-four racing engine which powered the car that won the 1912 French Grand Prix . Another Peugeot with a DOHC engine won the 1913 French Grand Prix , followed by the Mercedes-Benz 18/100 GP with an SOHC engine winning the 1914 French Grand Prix . The Isotta Fraschini Tipo KM — built in Italy from 1910–1914—
1863-427: The 1925-1948 Velocette K series , the 1931-1957 Norton International and the 1947-1962 Norton Manx . In more recent times, the 1950-1974 Ducati Single , 1973-1980 Ducati L-twin engine , 1999-2007 Kawasaki W650 and 2011-2016 Kawasaki W800 motorcycle engines have used bevel shafts. The Crosley four cylinder was the last automotive engine to use the shaft tower design to drive the camshaft, from 1946 to 1952;
1932-417: The 1928-1931 MG 18/80 , the 1926–1935 Singer Junior and the 1928–1929 Alfa Romeo 6C Sport . Early overhead camshaft motorcycles included the 1925–1949 Velocette K Series and the 1927–1939 Norton CS1 . The 1946–1948 Crosley CC Four was arguably the first American mass-produced car to use an SOHC engine. This small mass-production engine powered the winner of the 1950 12 Hours of Sebring . Use of
2001-511: The 1950s, however the problems of "turbo lag" and the bulky size of the turbocharger were not able to be solved at the time. The first turbocharged cars were the short-lived Chevrolet Corvair Monza and the Oldsmobile Jetfire , both introduced in 1962. Greater adoption of turbocharging in passenger cars began in the 1980s, as a way to increase the performance of smaller displacement engines. Like other forced induction devices,
2070-529: The United States. In 1965, Meyer was bought out by Drake, his wife Eve and their son John. From then until Drake's son John sold the shop to Stewart Van Dyne, the Drake family designed and refined the engine until its final race days. One of the keys to the Offenhauser engine's success and popularity was its power. A 251.92 cubic inch (4,128.29 cm³) DOHC naturally-aspirated four-cylinder racing Offy with
2139-738: The advent of turbocharging . A more powerful turbocharged version of the engine was used by Offenhauser in 1968 , and gave Bobby Unser the win that year. The engine made 750 hp (560 kW) @ 9,500 rpm, from a displacement of only 168 cu in (2,750 cc). Outputs over 1,000 bhp (750 kW) could be attained, using around 44.3 psi (3.05 bar) of boost pressure. The final 2.65-litre four-cylinder Offy, restricted to 24.6 psi (1.70 bar) boost, produced 770 bhp (570 kW) at 9,000 rpm. The Offy's final victory came at Trenton in 1978, in Gordon Johncock 's Wildcat. The last time an Offy-powered car raced
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2208-475: The aim of overcoming the power loss experienced by aircraft engines due to the decreased density of air at high altitudes. However, the prototype was not reliable and did not reach production. Another early patent for turbochargers was applied for in 1916 by French steam turbine inventor Auguste Rateau , for their intended use on the Renault engines used by French fighter planes. Separately, testing in 1917 by
2277-455: The bankruptcy auction, and he and other former Miller employees took over production. They and former Miller employee, draftsman Leo Goossen , further developed the Miller engines into the Offenhauser engines. In 1946, the name Offenhauser and engine designs were sold to Louis Meyer and Dale Drake. It was under Meyer and Drake that the engine dominated the Indianapolis 500 and midget racing in
2346-406: The benefits of both small turbines and large turbines. Large diesel engines often use a single-stage axial inflow turbine instead of a radial turbine. A twin-scroll turbocharger uses two separate exhaust gas inlets, to make use of the pulses in the flow of the exhaust gasses from each cylinder. In a standard (single-scroll) turbocharger, the exhaust gas from all cylinders is combined and enters
2415-519: The block, and were known as "tower shafts". An early American overhead camshaft production engine was the SOHC straight-eight engine used in the 1921–1926 Duesenberg Model A luxury car. In 1926, the Sunbeam 3 litre Super Sports became the first production car to use a DOHC engine. In the United States, Duesenberg added DOHC engines (alongside their existing SOHC engines) with the 1928 release of
2484-461: The camshaft (usually a timing chain in modern engines) is more complex in an OHC engine, such as the 4-chain valvetrain of the Audi 3.2 or the 2 meter chain on Ford cammers. Another disadvantage of OHC engines is that during engine repairs where the removal of the cylinder head is required, the camshaft engine timing needs to be reset. In addition, an OHC engine has a large cylinder head to accommodate
2553-408: The camshaft is located below the combustion chamber in the engine block . Single overhead camshaft (SOHC) engines have one camshaft per bank of cylinders . Dual overhead camshaft (DOHC, also known as "twin-cam" ) engines have two camshafts per bank. The first production car to use a DOHC engine was built in 1910. Use of DOHC engines slowly increased from the 1940s, leading to many automobiles by
2622-409: The camshaft is usually transferred to the valves either directly (using a tappet) or indirectly via a rocker arm . A dual overhead cam , double overhead cam , or twin-cam engine has two camshafts over each bank of the cylinder head, one for the intake valves and another for the exhaust valves. Therefore there are two camshafts for a straight engine and a total of four camshafts for a V engine or
2691-510: The camshaft or an extra set of valves to increase the volumetric efficiency , so that with the same displacement as an OHV engine, the OHC engine will end up being the physically larger of the two mostly due to the enlarged cylinder head. The other main advantage of OHC engines is that there is greater flexibility to optimise the size, location and shape of the intake and exhaust ports, since there are no pushrods that need to be avoided. This improves
2760-415: The camshaft. Timing belts are inexpensive, produce minimal noise and have no need for lubrication. A disadvantage of timing belts is the need for regular replacement of the belt; recommended belt life typically varies between approximately 50,000–100,000 km (31,000–62,000 mi). If the timing belt is not replaced in time and fails and the engine is an interference engine , major engine damage
2829-421: The compressor wheel. Large turbines typically require higher exhaust gas flow rates, therefore increasing turbo lag and increasing the boost threshold. Small turbines can produce boost quickly and at lower flow rates, since it has lower rotational inertia, but can be a limiting factor in the peak power produced by the engine. Various technologies, as described in the following sections, are often aimed at combining
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2898-419: The compressor. The compressor draws in outside air through the engine's intake system, pressurises it, then feeds it into the combustion chambers (via the inlet manifold ). The compressor section of the turbocharger consists of an impeller, a diffuser, and a volute housing. The operating characteristics of a compressor are described by the compressor map . Some turbochargers use a "ported shroud", whereby
2967-466: The crankshaft and the camshaft is commonly used in diesel overhead camshaft engines used in heavy trucks. Gear trains are not commonly used in engines for light trucks or automobiles. Several OHC engines up until the 1950s used a shaft with bevel gears to drive the camshaft. Examples include the 1908–1911 Maudslay 25/30 , the Bentley 3 Litre , the 1917-? Liberty L-12 , the 1929-1932 MG Midget ,
3036-443: The early 2000s using DOHC engines. In an OHC engine, the camshaft is located at the top of the engine, above the combustion chamber . This contrasts the earlier overhead valve engine (OHV) and flathead engine configurations, where the camshaft is located down in the engine block . The valves in both OHC and OHV engines are located above the combustion chamber; however an OHV engine requires pushrods and rocker arms to transfer
3105-413: The effective aspect ratio of the turbocharger as operating conditions change. This is done with the use of adjustable vanes located inside the turbine housing between the inlet and turbine, which affect flow of gases towards the turbine. Some variable-geometry turbochargers use a rotary electric actuator to open and close the vanes, while others use a pneumatic actuator . If the turbine's aspect ratio
3174-403: The engine rpm is within the turbocharger's operating range – that occurs between pressing the throttle and the turbocharger spooling up to provide boost pressure. This delay is due to the increasing exhaust gas flow (after the throttle is suddenly opened) taking time to spin up the turbine to speeds where boost is produced. The effect of turbo lag is reduced throttle response , in
3243-559: The engine's coolant to flow through. One reason for water cooling is to protect the turbocharger's lubricating oil from overheating. The simplest type of turbocharger is the free floating turbocharger. This system would be able to achieve maximum boost at maximum engine revs and full throttle, however additional components are needed to produce an engine that is driveable in a range of load and rpm conditions. Additional components that are commonly used in conjunction with turbochargers are: Turbo lag refers to delay – when
3312-491: The engine's success was its reliability. Its monobloc construction made it immune to head gasket or cylinder stud problems, and allowed for higher cylinder pressures . From 1934 through the 1970s, the Offenhauser engine dominated American open-wheel racing , winning the Indianapolis 500 27 times. From 1950 through 1960, Offenhauser-powered cars won the Indianapolis 500 and achieved all three podium positions, winning
3381-482: The exhaust gases, minimizes parasitic back losses and improves responsiveness at low engine speeds. Another common feature of twin-scroll turbochargers is that the two nozzles are different sizes: the smaller nozzle is installed at a steeper angle and is used for low-rpm response, while the larger nozzle is less angled and optimised for times when high outputs are required. Variable-geometry turbochargers (also known as variable-nozzle turbochargers ) are used to alter
3450-404: The form of a delay in the power delivery. Superchargers do not suffer from turbo lag because the compressor mechanism is driven directly by the engine. Methods to reduce turbo lag include: A similar phenomenon that is often mistaken for turbo lag is the boost threshold . This is where the engine speed (rpm) is currently below the operating range of the turbocharger system, therefore the engine
3519-490: The gas flow through the engine, increasing power output and fuel efficiency . The oldest configuration of overhead camshaft engine is the single overhead camshaft (SOHC) design. A SOHC engine has one camshaft per bank of cylinders, therefore a straight engine has a total of one camshaft and a V engine or flat engine has a total of two camshafts (one for each cylinder bank). Most SOHC engines have two valves per cylinder, one intake valve and one exhaust valve. Motion of
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#17327724753983588-405: The gas flow through the turbine section, and the turbine itself can spin at speeds of up to 250,000 rpm. Some turbocharger designs are available with multiple turbine housing options, allowing a housing to be selected to best suit the engine's characteristics and the performance requirements. A turbocharger's performance is closely tied to its size, and the relative sizes of the turbine wheel and
3657-502: The intake air. A combination of an exhaust-driven turbocharger and an engine-driven supercharger can mitigate the weaknesses of both. This technique is called twincharging . Turbochargers have been used in the following applications: In 2017, 27% of vehicles sold in the US were turbocharged. In Europe 67% of all vehicles were turbocharged in 2014. Historically, more than 90% of turbochargers were diesel, however, adoption in petrol engines
3726-431: The mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. Prior to the invention of the turbocharger, forced induction was only possible using mechanically-powered superchargers . Use of superchargers began in 1878, when several supercharged two-stroke gas engines were built using a design by Scottish engineer Dugald Clerk . Then in 1885, Gottlieb Daimler patented
3795-407: The motion from the camshaft up to the valves, whereas an OHC engine has the valves directly actuated by the camshaft. Compared with OHV engines with the same number of valves, there are fewer reciprocating components and less valvetrain inertia in an OHC engine. This reduced inertia in OHC engines results in less valve float at higher engine speeds (RPM). A downside is that the system used to drive
3864-399: The range of rpm where boost is produced, or simplify the layout of the intake/exhaust system. The most common arrangement is twin turbochargers, however triple-turbo or quad-turbo arrangements have been occasionally used in production cars. The key difference between a turbocharger and a supercharger is that a supercharger is mechanically driven by the engine (often through a belt connected to
3933-454: The rights to the Crosley engine format were bought by a few different companies, including General Tire in 1952, followed by Fageol in 1955, Crofton in 1959, Homelite in 1961, and Fisher Pierce in 1966, after Crosley closed the automotive factory doors, and they continued to produce the same engine for several more years. A camshaft drive using three sets of cranks and rods in parallel
4002-436: The rotational force is produced, in order to power the compressor (via a rotating shaft through the center of a turbo). After the exhaust has spun the turbine it continues into the exhaust piping and out of the vehicle. The turbine uses a series of blades to convert kinetic energy from the flow of exhaust gases to mechanical energy of a rotating shaft (which is used to power the compressor section). The turbine housings direct
4071-730: The starting point for both Mercedes' and Rolls-Royce's aircraft engines. Mercedes created a series of six-cylinder engines which culminated in the Mercedes D.III . Rolls-Royce reversed-engineered the Mercedes cylinder head design based on a racing car left in England at the beginning of the war, leading to the Rolls-Royce Eagle V12 engine. Other SOHC designs included the Spanish Hispano-Suiza 8 V8 engine (with
4140-400: The technique of using a gear-driven pump to force air into an internal combustion engine. The 1905 patent by Alfred Büchi , a Swiss engineer working at Sulzer is often considered the birth of the turbocharger. This patent was for a compound radial engine with an exhaust-driven axial flow turbine and compressor mounted on a common shaft. The first prototype was finished in 1915 with
4209-447: The timing between each camshaft and the crankshaft. This affords better fuel economy by allowing a broader torque curve. Although each major manufacturer has their own trade name for their specific system of variable cam phasing systems, overall they are all classified as variable valve timing . The rotation of a camshaft is driven by a crankshaft . Many 21st century engines use a toothed timing belt made from rubber and kevlar to drive
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#17327724753984278-437: The top of the engine. Large aircraft engines— particularly air-cooled engines— experienced considerable thermal expansion, causing the height of the cylinder block to vary during operating conditions. This expansion caused difficulties for pushrod engines, so an overhead camshaft engine using a shaft drive with sliding spline was the easiest way to allow for this expansion. These bevel shafts were usually in an external tube outside
4347-500: The turbocharger via a single intake, which causes the gas pulses from each cylinder to interfere with each other. For a twin-scroll turbocharger, the cylinders are split into two groups in order to maximize the pulses. The exhaust manifold keeps the gases from these two groups of cylinders separated, then they travel through two separate spiral chambers ("scrolls") before entering the turbine housing via two separate nozzles. The scavenging effect of these gas pulses recovers more energy from
4416-414: The valves directly via a bucket tappet . A DOHC design permits a wider angle between intake and exhaust valves than in SOHC engines, which improves the air-fuel mixture's flow through the engine. A further benefit is that the spark plug can be placed at the optimum location, which in turn improves combustion efficiency . Another newer benefit of DOHC engine design is the ability to independently change/phase
4485-460: Was at Pocono in 1982 for the Domino's Pizza Pocono 500 , in an Eagle chassis driven by Jim McElreath , although two Vollstedt chassis with Offenhauser engines failed to qualify for the 1983 Indianapolis 500. Offenhauser produced engine blocks in several sizes. These blocks could be bored out or sleeved to vary the cylinder bore, and could be used with crankshafts of various strokes, resulting in
4554-520: Was one of the first production cars to use an SOHC engine. During World War I, both the Allied and Central Powers ; specifically those of the German Empire 's Luftstreitkräfte air forces, sought to quickly apply the overhead camshaft technology of motor racing engines to military aircraft engines. The SOHC engine from the Mercedes 18/100 GP car (which won the 1914 French Grand Prix) became
4623-472: Was the 1962 Glas 1004 compact coupe. Another camshaft drive method commonly used on modern engines is a timing chain , constructed from one or two rows of metal roller chains . By the early 1960s most production automobile overhead camshaft designs used chains to drive the camshaft(s). Timing chains do not usually require replacement at regular intervals, however the disadvantage is that they are noisier than timing belts. A gear train system between
4692-696: Was used by the German Ministry of Transport for two large passenger ships called the Preussen and Hansestadt Danzig . The design was licensed to several manufacturers and turbochargers began to be used in marine, railcar and large stationary applications. Turbochargers were used on several aircraft engines during World War II, beginning with the Boeing B-17 Flying Fortress in 1938, which used turbochargers produced by General Electric. Other early turbocharged airplanes included
4761-474: Was used in the 1920–1923 Leyland Eight luxury car built in the United Kingdom. A similar system was used in the 1926-1930 Bentley Speed Six and the 1930-1932 Bentley 8 Litre . A two-rod system with counterweights at both ends was used by many models of the 1958-1973 NSU Prinz . Among the first overhead camshaft engines were the 1902 Maudslay SOHC engine built in the United Kingdom and
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