A straight-four engine (also referred to as an inline-four engine ) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft.
89-450: The Lotus-Ford Twin Cam is an inline-four petrol engine developed by Lotus for the 1962 Lotus Elan . A few early examples displaced 1.5 litres, but the majority were 1.55-litre (1557cc) engines. It used a Ford 116E iron cylinder block and a new aluminium cylinder head with dual overhead camshafts . The Twin Cam was used in a variety of vehicles until Lotus stopped production in 1973. It
178-400: A secondary imbalance . This is caused by the acceleration/deceleration of the pistons during the top half of the crankshaft rotation being greater than that of the pistons in the bottom half of the crankshaft rotation (because the connecting rods are not infinitely long). As a result, two pistons are always accelerating faster in one direction, while the other two are accelerating more slowly in
267-420: A "giant killer" often beating cars in larger classes, but the limited road adhesion due to the narrow tyre width became apparent as the shortcoming in running with the larger cars. The 23C was developed using much wider Formula Two tyres mounted on wider 6-stud, six-spoke magnesium wheels front and rear. The body received wing-extensions to cover the wider tyres, with the characteristic 23/23B rear wings (covering
356-676: A 600 cc (36.6 cu in) inline-four engine made by Honda based on the CBR600RR with a maximum power output of 110 kW (150 hp). Starting in 2019 , the engines were replaced by a Triumph 765 cc (46.7 cu in) triple engine . Inline-four engines are also used in light duty commercial vehicles such as Karsan Jest and Mercedes-Benz Sprinter . Lotus 23 748cc Coventry Climax FWMB 997cc Cosworth Mk.III 1098cc Cosworth Mk.IV 1340cc Cosworth Mk.VI 1475cc Cosworth Mk.VII 1498cc Cosworth Mk.X 23B & 23C: Hewland Mk.IV The Lotus 23
445-558: A BRM name plate on a specially cast 'BRM' cam cover, but the actual assembly of these high performance 'BRM' road engines was carried out by Rubery Owen & Co. Ltd. , an affiliated company of BRM through its ownership, not by BRM itself. The Special Equipment ('S/E') engines had 26/66/66/26 cam timing. Originally applied to tuned Elans and Lotus Cortinas, the term "Special Equipment" was later used by Lotus to designate those Series 2 and later Elans with higher output motors, and are referred to as Elan S/Es. In 1968 Sanville began building
534-599: A French publication, suggesting the Ferrari 246SP and 268SP had the same ground clearance issue, but were allowed to race unrectified after the Ferrari team threatened to withdraw the entire team) present as the interpreter in the meeting, Chapman suggested a figure which was too large for the officials to swallow. Upon being rejected, Chapman vowed "We will never race again at Le Mans!", a promise that Lotus kept until 1997, long after Chapman's death in 1982. Chapman believed
623-463: A Lotus 23 replica in 1996 with a wider track than the original to allow for the use of wider tyres. With a lower level of adherence to the original design than the Xanthos, it proved successful in racing, with over 60 cars produced using either Lotus TwinCam or Renault V6 engines. Noble's version continued in production, first by Auriga Design using an Alfa Romeo engine and transaxle, and then as
712-666: A Twin Cam was a left hand drive Ford Anglia, and the engine was installed on 18 January 1962. This Anglia is reported to have overtaken a Jaguar at well over 100 mph (160 km/h) in the hands of Jim Clark on his way home to Scotland from Goodwood . In May 1962 Ford announced the 116E engine. This engine first appeared in the Consul Capri in August 1962, and then in the Cortina Super in January 1963. The 116E had
801-451: A cylinder on its power stroke, unlike engines with fewer cylinders where there is no power stroke occurring at certain times. Compared with a V4 engine or a flat-four engine , a straight-four engine only has one cylinder head , which reduces complexity and production cost. Petrol straight-four engines used in modern production cars typically have a displacement of 1.3–2.5 L (79–153 cu in), but larger engines have been used in
890-600: A displacement of 1.5–2.5 L (92–153 cu in). The smallest automotive straight-four engine was used in the 1963–1967 Honda T360 kei truck and has a displacement of 356 cc (21.7 cu in), while the largest mass-produced straight-four car engine is the 1999–2019 Mitsubishi 4M41 diesel engine which was used in the Mitsubishi Pajero and has a displacement of 3.2 L (195 cu in). Significant straight-four car engines include: Many early racing cars used straight-four engines, however
979-441: A measurable increase in power. The majority of the power gain comes from modifying the size and shape of the intake runners (porting) and fitting uprated camshafts. Different sources report different, sometimes conflicting information with regard to naming, power outputs, and other items. Some of these are listed below. Cosworth founders Keith Duckworth and Mike Costin were both former employees of Lotus. Their new company developed
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#17327879165761068-508: A reflection of strength requirement in the original design, so the 4 stud configuration was deemed unsafe. This is a rare "picture" . of Les Leston Lotus 23 with tall windscreen and 4 stud rear hub. The scrutineers and the ACO did not change this position even after Mike Costin , the Lotus engineer on site, offered to go over structural analysis calculations showing the difference falls within
1157-758: A series of Twin Cams using a new camshaft called the Super Special Equipment cam, or D-Type, that was based on the Coventry Climax FWA 3060 cam. Heads used in SSE engines were shaved by 0.04 in (1.0 mm), boosting the compression ratio to 10.3:1. The ignition was advanced slightly, and larger chokes and different jets were fitted to the Weber carburettors. Power was estimated to be 124–126 bhp (92.5–94.0 kW), fully three years prior to
1246-437: A spare tyre is for the purpose of changing a flat, which is not satisfied by the 23 in the case of a flat occurring on one of the rear tyres. So the Lotus factory had a 4 stud rear hubs drafted and machined over-night, and had a person carry them and flown to Le Mans the next day. After being presented with the 23s with 4 stud rears installed, the scrutineers rejected again on the grounds that the 6 stud configuration must have been
1335-416: A taller deck height than the earlier Kent engines, and with a bore and stroke of 3 + 3 ⁄ 16 in × 2.864 in (80.96 mm × 72.75 mm), capacity was 1.5 L; 91.4 cu in (1,498 cc). The 116E's crankshaft was carried on five main-bearings. Power output was about 60 bhp (45 kW) at 4600 rpm. As soon as a block could be obtained work began to convert
1424-591: A testament. In 1964 Le Mans , Alpine won the Index of Thermal Efficiency with the M64 while setting a new distance record for the 1150cc Prototype class, with a M63B in the second place. Alpine went on to become the Le Mans overall winner in 1978 . Beginning in the early 1980s a small group of enthusiasts began to make it possible to restore original Lotus 23 by remanufacturing parts. These parts are now easily available. It
1513-401: A time when regulations dictated a maximum displacement of 550 cc; the maximum size is currently at 660 cc. Straight-four engines with the preferred crankshaft configuration have perfect primary balance . This is because the pistons are moving in pairs, and one pair of pistons is always moving up at the same time as the other pair is moving down. However, straight-four engines have
1602-500: A windshield wiper, a horn, pairs of headlights and tail lights, rear center licence plate light, a cable-operated hand brake , and a mounting space for one spare tire under the front body. The 23 used a wider version of the Lotus 22 space frame , clothed in a fiberglass body. It was originally intended for engines of 750 cc to 1300 cc (45-80ci) with a Renault 4-speed transaxle, but had a 5-speed Hewland Mk.III in production, which used
1691-517: Is particularly beneficial in the higher rpm range, and " big-bang firing order " theory says the irregular delivery of torque to the rear tire makes sliding in the corners at racing speeds easier to control. Inline-four engines are also used in MotoGP by the Suzuki (since 2015 ) and Yamaha (since 2002 ) teams. In 2010 , when the four-stroke Moto2 class was introduced, the engines for the class were
1780-470: The Maserati 4CL and various English Racing Automobiles (ERA) models. These were resurrected after the war, and formed the foundation of what was later to become Formula One , although the straight-eight supercharged Alfettas would dominate the early years of F1. Another engine that played an important role in racing history is the straight-four Ferrari engine designed by Aurelio Lampredi . This engine
1869-666: The Mk.XVI , a version of the Mk.XIII for the 1.5 Liter Class. Cosworth designed its own aluminium reverse-flow 2-valve gear-driven SOHC cylinder head for the same Ford 116E block. This head shared many basic design attributes with the Coventry Climax FWE head and was used with a short-stroke forged steel crank for a 1 Liter Formula 2 engine named the SCA in 1964. This was followed by a gear-driven DOHC 4-valve cross-flow aluminium head on
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#17327879165761958-533: The 1920s and early 1930s. The Miller engine evolved into the Offenhauser engine which had a highly successful spanning from the 1933 until 1981, including five straight victories at the Indianapolis 500 from 1971 to 1976. Many cars produced for the pre-WWII voiturette Grand Prix motor racing category used inline-four engine designs. 1.5 L supercharged engines found their way into cars such as
2047-441: The 1970s. Since then, the inline-four has become one of the most common engine configurations in street bikes. Outside of the cruiser category, the inline-four is the most common configuration because of its relatively high performance-to-cost ratio. All major Japanese motorcycle manufacturers offer motorcycles with inline-four engines, as do MV Agusta and BMW . BMW's earlier inline-four motorcycles were mounted horizontally along
2136-408: The 1L Sportscar class with the 8th overall result, beating the winners of 3L Prototype class ( Maserati Tipo 61 CDM) and 1L Prototype class (Midship DOHC engine René Bonnet Djet III ) by 3 laps. It also beat a 3L Sportscar class Ferrari 250 Testa Rossa , 2L Prototype class Alfa Romeo Giulietta SZ and a 4L Prototype class Jaguar E-Type . With the sensational Nürburgring debut well publicised in
2225-469: The 2.4 litre Citroën DS engine, the 2.6 litre Austin-Healey 100 engine, the 3.3 L Ford Model A (1927) engine and the 2.5 L GM Iron Duke engine . Soviet/Russian GAZ Volga and UAZ engines with displacements of up to 2.9 litres were produced without balance shafts from the 1950s to the 1990s, however these were relatively low-revving engines which reduces the need for a balance shaft system. Most modern straight-four engines used in cars have
2314-709: The Cortina-Lotus to the Ford Cortina Mark II -based Cortina Twin Cam in 1967, Ford began to call the engine the "Lotus-Ford Twin Cam". The engine is also known informally as the "Lotus TC" or the "Twink". Although the Twin Cam's displacement is usually listed as 1,558 cc (1.6 L), its bore and stroke are 82.55 mm × 72.75 mm ( 3 + 1 ⁄ 4 in × 2.864 in) respectively, for an actual displacement of 1,557.46 cc (1.6 L; 95.0 cu in). This allowed
2403-675: The Cosworth Mk.XVI form during the 1 + 1 ⁄ 2 -litre (92 cu in) formula that ran from 1961-65. Its first appearance was at the 1963 South African Grand Prix in a Brabham BT6 driven by David Prophet . The engine appeared in two cars in the 1964 British Grand Prix , one being the Gerard Racing Cooper T73 driven by John Taylor and the other the John Willment Automobiles Brabham BT10 . The only recorded finish
2492-481: The DOHC cam sprockets were driven by a long front-mounted, single-row 3 ⁄ 8 -inch (9.5 mm) Reynolds roller timing chain . Early Lotus blocks were simply standard Ford production line items selected for having the thickest cylinder walls, and were identified by an "A" stamped into the timing cover mating face. Later blocks were specially cast with Twin Cam production in mind and identified by an "L" cast into
2581-549: The Formula classes. Roger Barr won the 1968 US Formula B National Championship using a Twin Cam, with numerous modifications made to both it and the Crossle chassis. Inline-four engine The majority of automotive four-cylinder engines use a straight-four layout (with the exceptions of the flat-four engines produced by Subaru and Porsche) and the layout is also very common in motorcycles and other machinery. Therefore
2670-513: The Lotus cylinder head to the 116E block. Duckworth assembled the first two production-specification engines, one of which powered a Lotus 23 on its racing debut at the Nürburgring . After building a limited number of 1.5 L Twin Cams, the bore was increased to 82.55 mm ( 3 + 1 ⁄ 4 in), raising the capacity to 1.56 L. Assembly of the first 50 engines was contracted out to J.A.Prestwich . Prestwich also machined
2759-422: The Mk.IV and Mk.V transaxles had GKN ( Ford Zephyr ) differential gears and a forward-facing selector rod on the right side in a bespoke (Hewland made) tail casing. The intake funnels on the Weber carburetors on 23B (and the 23C) were housed in a "cold air box" which received fresh air from two oval holes cut out on the top side of the rear body behind the driver. The 23B proved to be very successful in being
Lotus-Ford Twin Cam - Misplaced Pages Continue
2848-515: The Peugeot engine which won the 1913 Indianapolis 500 was a highly influential engine. Designed by Ernest Henry , this engine had double overhead camshafts (DOHC) with four valves per cylinder, a layout that would become the standard until today for racing inline-four engines. Amongst the engines inspired by the Peugeot design was the Miller engine , which was a successful racing engine through
2937-425: The Twin Cam for competition use under Cosworth Project Code TA , with specific versions designated with an 'Mk.' prefix. One of the initial batch became the experimental Cosworth Mk.X in 1962. This was followed in 1963 by the dry-sump Mk.XII with racing camshafts designated the 'CPL2' (26/66/66/26) and high compression Cosworth pistons, used actively by Team Lotus in Lotus 20B , 22 , 23 and 23B . The Mk.XII
3026-455: The Twin Cam to be over-bored by up to 1 mm (0.04 in) and still remain below the 1600 cc class limit permitted by FIA regulations. The displacement error goes back to 27 May 1963 when the FIA homologation papers were submitted on 1962-model (Series 1) Lotus Elan by Lotus Cars Ltd. and accepted by Royal Automobile Club for FIA. The papers listed the engine capacity as 1558 cc with
3115-657: The United States, Nimbus in Denmark, Windhoff in Germany, and Wilkinson in the United Kingdom. The first across-the-frame 4-cylinder motorcycle was the 1939 racer Gilera 500 Rondine , it also had double-over-head camshafts, forced-inducting supercharger and was liquid-cooled . Modern inline-four motorcycle engines first became popular with Honda 's SOHC CB750 introduced in 1969, and others followed in
3204-399: The basis of this new engine. The 105E displaced 1.0 L; 60.8 cu in (997 cc) and had a cast iron block produced with Ford's thin-wall casting process, resulting in a relatively light part. While the 105E block only provided three main bearings for the crankshaft , the oversquare design kept piston speeds down and gave room for larger valves in the new cylinder head. When
3293-419: The block under the engine mount. Twin Cam blocks came from 6 basic casting versions. Prior to 1968 the first 4 digits were often ground off the block and "3020" was stamped in its place. Early engines used a crankshaft, connecting rods and pistons from Lotus. The crank was cast iron, and the pistons had a slight crown and were fly-cut to clear the valves. A revised Twin Cam was released in 1966. In this version
3382-494: The bodywork, a following driver with good eyesight could tell when the 23 with Hewland Mk.III shifted gears. The front suspension was a typical double wishbone arms with outboard coil/damper unit using the Triumph upright made by Alford & Alder , Triumph Herald rack and pinion steering, and outboard Girling non-ventilated disc brake. The rear had the top link with lower reversed wishbone, top and bottom radius arms with
3471-488: The cam cover above each camshaft. Later engines had a raised border across the front of the cam cover with the word "Lotus" cast in raised text set within it. The portion of the cover over the cams was smooth. Lotus began to offer more highly tuned Special Equipment engines as options in their cars. The parts for these engines could also be bought from Lotus Components Ltd. At first, these were Cosworth developed and assembled engines with cast cranks and Cosworth name plates on
3560-554: The cam cover. Duckworth was responsible for the design of the Special Equipment cams. Cosworth later distanced themselves from this business, and Lotus started selling ' equivalents. BRM Phase I consisted of BRM camshafts and high compression cast pistons, and BRM Phase II added Mahle forged pistons, BRM forged conrods, small-end bushes and big-end bolts to the Phase I. When offered in assembled form, these engines carried
3649-597: The coolant circuit in sprint races, and displayed a very stable water/oil temperature in endurance racing. The 23B in 1963 had the original center gear shifter relocated to the right side of the driver, and the radiator and oil cooler were combined into a single unit, with the lower 1/5 or so acting as the oil cooler. The frame received additional structural tubes to take the torque of Lotus TwinCam -based 1.6 litre Cosworth Mk.XII and Mk.XIII , mated to "high torque spec" 5-speed Hewland Mk.V transaxle. Smaller displacement engines were mated to 5-speed Hewland Mk.IV . Both
Lotus-Ford Twin Cam - Misplaced Pages Continue
3738-519: The correct bore and stroke sizes. Ironically, the over-bore limit of 1 mm is also stated in the paper with the correct resultant displacement of 1,595 cc (83.55 mm x 72.75 mm, 1,595.42 cc). The cylinder head has hemispherical combustion chambers (correct statement would have been "pear shaped chambers" since this has implications on the angle of the valves). Valve sizes are 1.53 in (39 mm) diameter inlet and 1.325 in (33.7 mm) diameter exhaust on all engines except
3827-479: The cover over the camshafts had raised ribs cast in. Big Valve engines had the same 26/66/66/26 timing as the S/E engines but with 0.360 in (9.1 mm) lift. "Special" spec engines had 26/66/66/26 timing with 0.362 in (9.2 mm) lift. The larger inlet valves are compatible with earlier non Big Valve cylinder heads with very little modification, however increasing intake valve size by itself will not produce
3916-401: The engine and support contract attached, on a strict condition imposed by Chapman to keep the 4 stud configuration for longer than one racing season. The French driver/buyer, Bernard Consten [ fr ] , not only obliged but won Clermont-Ferrand 6 Hours and 1000 km of Montlhery that year with this 23 without breaking the studs, the hub, or the wheel. Team Lotus remained on
4005-406: The engine front cover as its housing, making water pump replacement difficult. The intake manifold was a series of short tubular stubs cast as an integral part of the cylinder head. The heads for 175CD Zenith - Stromberg carburettor had two siamesed stubs (part of the head casting), making them not interchangeable with earlier heads using Dell'Orto DHLA40 or 40DCOE Weber carburetors , whose intake
4094-524: The entire Volkswagen magnesium alloy transaxle case in upside-down configuration, housing bespoke straight-cut gears with dog-rings, and the Volkswagen differential gear set. Unlike the later Mk.IV/V, the Mk.III had the shifter rod at the end of the VW nose casing, so the shifting rod (pipe) from the centre shifter knob location extended to the tail end of the chassis. As this part was not completely covered by
4183-411: The extended top end of cast alloy upright. The tie-rod end, front top and bottom wishbone outside joints were ball joints , and the rear lower wishbone inside joints were Rose joint . The rest of the suspension joints were rubber joint, with joint-mounting pipes welded onto the ends of suspension arms. While most of the suspension arms were in common with Lotus 22, the angle of the rear radius arms on
4272-595: The failure-prone original on the 1.6-litre inline four Pont-à-Mousson engine used in the Facellia . Financial problems at Facel kept either engine from reaching production, but when Chapman found out about the smaller engine he commissioned Mundy to adapt the Facellia design to the Ford engine block. Mundy's design for Lotus comprised an aluminium cylinder head and an aluminium front cover and its back plate assembly containing
4361-467: The fiasco was caused by the French contender for Index of Thermal Efficiency award, René Bonnet . Gérard Crombac knew of a competitor to Bonnet, Jean Rédélé , who had a strong ambition to beat the then-dominant Automobiles René Bonnet in thermal efficiency at Le Mans , and gave the idea of helping Alpine instead of subsequent direct participation to Chapman. As a result, a 2-seater racing prototype
4450-400: The fly-cuts were smaller, and the con-rods were Ford 125E parts. The flywheel was also attached to the crankshaft by six bolts, an increase of two over the previous model. The Twin Cam had a problem with oil surge, and the attachment of the starter motor was subject to flexing when trying to spin the high-compression engine. Early engines had the word "Lotus" in script cast in raised letters on
4539-471: The frame, but all current four-cylinder BMW motorcycles have transverse engines . The modern Triumph company has offered inline-four-powered motorcycles, though they were discontinued in favour of triples . The 2009 Yamaha R1 has an inline-four engine that does not fire at even intervals of 180°. Instead, it uses a crossplane crankshaft that prevents the pistons from simultaneously reaching top dead centre. This results in better secondary balance , which
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#17327879165764628-448: The head joint. Keith Duckworth , who had already left Lotus for Cosworth Engineering , was brought back to look at the new cylinder head. Duckworth made several design changes, reshaping the ports and adding structure to the head. The first Lotus Twin Cam engine was fired up on a test bench on October 10, 1961. This engine broke a crankshaft during testing; a failure blamed on the three main-bearing block. The first test vehicle to receive
4717-567: The large 2,495 cc FPF that won the Formula One championship in Cooper 's chassis in 1959 and 1960. In Formula One, the 1980s were dominated by the 1,500 cc turbocharged cars. The BMW M12/13 engine was notable for the era for its high boost pressures and performance. The cast iron block was based on a standard road car block and powered the F1 cars of Brabham, Arrows and Benetton and won
4806-471: The larger 1.3 L; 81.7 cu in (1,339 cc) 109E for the Ford Consul Classic was released, it became the platform for most of the development of the new Lotus engine. Engine designer Harry Mundy had been working on two projects for Jean Daninos ' Facel S.A. One design was an all-new quad-cam V6 displacing under 3.0 litres. The other was a new DOHC cylinder head to replace
4895-536: The larger valves and installed Super Special Equipment D-type camshafts. Power was increased 20% over the regular engine's 105 to 126 hp (78.3 to 94.0 kW). Big Valve engines were offered in the Elan Sprint, Elan +2 130, and Lotus Europa Twin Cam Special models. Cam covers for Big Valve engines had the words "Lotus" and "Big Valve" cast in raised letters across the front of the cam cover. The portion of
4984-624: The later "Big Valve" engines. The valve stem axis is inclined 27° from vertical on both intake and exhaust. Initial cam timing was 15/53/53/15 with the same cam profile as the ET418 Coventry Climax FWE cam, which resulted in 100 bhp (75 kW; 101 PS) at 5700 rpm for the 1,498cc engine with a 9.5:1 compression ratio. 1,557cc production engines had 22/62/62/22 cam timing with 0.349 in (8.9 mm) lift (developed by Cosworth as 'CPL1' -Cosworth Production Lotus) with 9.8:1 compression ratio. The water pump used
5073-602: The now-viable engineering firm to reduce its previous near-total dependence on Lotus. The proliferation of the Mk.XIII triggered the establishment of new European-style racing-engine builders in the US performing rebuilding and maintenance work needed on the Mk.XIII while also contributing to Cosworth's revenue. Other Cosworth engines based on the Lotus-Ford Twin Cam include the Mk.XV for the Lotus 26R and Lotus Cortina (almost all for Team Lotus and affiliated teams) and
5162-730: The oil pump drive cam to keep the interchangeability with the wet-sump Mk.XV. The Mk.XIII became a big seller in 1965 when the SCCA created the Formula B category in America. The dominance of the Mk.XIII in Formula B was nearly absolute against its main rivals the Satta / Hruska -designed Alfa Romeo 105/115 1.6 L (1,570 cc) DOHC unit, and the Alex von Falkenhausen-designed SOHC 1.6 L (1,573 cc) BMW M116 engine. This in turn allowed
5251-420: The other direction, which leads to a secondary dynamic imbalance that causes an up-and-down vibration at twice crankshaft speed. This imbalance is common among all piston engines, but the effect is particularly strong on four-stroke inline-four because of the two pistons always moving together. The strength of this imbalance is determined by the reciprocating mass, the ratio of connecting rod length to stroke, and
5340-756: The past, for example the 1927–1931 Bentley 4½ Litre . Diesel engines have been produced in larger displacements, such as a 3.2 L turbocharged Mitsubishi engine (used the Pajero/Shogun/Montero SUV) and a 3.0 L Toyota engine. European and Asian trucks with a gross vehicle weight rating between 7.5 and 18 tonnes typically use inline four-cylinder diesel engines with displacements around 5 litres. Larger displacements are found in locomotive, marine and stationary engines. Displacement can also be very small, as found in kei cars sold in Japan. Several of these engines had four cylinders at
5429-405: The peak piston velocity. Therefore, small displacement engines with light pistons show little effect, and racing engines use long connecting rods. However, the effect grows quadratically with engine speed (rpm). Four-stroke engines with five or more cylinders are able to have at least one cylinder performing its power stroke at any given point in time. However, four-cylinder engines have gaps in
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#17327879165765518-424: The plan view was different from the narrower-frame Lotus 22, so they were not interchangeable with the 22. On the frame structure, the lower side pipes and the width-wise lower pipe behind the cockpit were rectangle tubes, with most of the other frame pipes being round steel tubes in various diameter. The upper left round pipe was used as the water feed pipe (the use of anti-freeze chemicals was prohibited by most of
5607-399: The power delivery, since each cylinder completes its power stroke before the next piston starts a new power stroke. This pulsating delivery of power results in more vibrations than engines with more than four cylinders. A balance shaft system is sometimes used to reduce the vibrations created by a straight-four engine, most often in engines with larger displacements. The balance shaft system
5696-568: The press, two 23s were entered at Le Mans in June 1962. One with a 742 cc (45.3 cu in) aluminium-block DOHC Coventry Climax FWMC with drivers Les Leston / Tony Shelly , and another with one litre Iron block pushrod Cosworth Mk.III with drivers Jim Clark / Trevor Taylor . The 23s failed to pass the scrutineering on several technical grounds, including an insufficient windscreen height, fuel tank capacity being too large, turning circle too large, ground clearance too small, and
5785-450: The race organisers at the time for the danger of making the tarmac slippery) for the radiator up front, and the lower right side pipe and a half of the width-wise lower rear cockpit pipe were used as the return path. Likewise, the upper right side pipe was the oil feed to the oil cooler, and the lower left tube was the return. This frame was mostly made by Arch Motors, carrying 'AM' serial number. This water/oil-bearing frame configuration
5874-536: The raw cylinder head castings (cast by William Mills) on these early twin cam engines. The Twin Cam had its official debut at the Earls Court Motor Show in October 1962. Total production of the engine was approximately 34,000 units, in 24 different varieties. Chapman named the engine the "Lotus Twin-Cam" at its introduction in 1962 and Lotus continued to use that name. When production switched from
5963-541: The release of the Big Valve engine. Some SSE engines are said to have left the factory in Super Weber S/E Elans. The Big Valve Twin Cam was a project of Lotus' Engineering Director Tony Rudd. Rudd reduced the deck height by 0.04 in (1.0 mm) to raise the compression ratio to 10.5:1, increased the diameter of the inlet valves to 1.565 in (39.8 mm), modified the inlet runners' shape for
6052-403: The safety margin built in the design to accommodate more powerful 1,098 cc (67.0 cu in) Cosworth Mk.IV and 1,475 cc (90.0 cu in) Cosworth Mk.VII engines. One of the two Lotus 23s with 4 stud rears, with Cosworth Mk.III 997 cc (60.8 cu in) engine, was sold off sans engine on the spot to the 1 litre class winning driver of the event, with a lease on
6141-648: The same block with a Mk.XIII forged crank for a new 1.6 Liter Formula 2 engine named the FVA in 1966. This is when Cosworth's involvement in the development of the Lotus TwinCam ended. The Twin Cam made its racing debut in May 1962 as a Cosworth Mk.X in a Lotus 23 driven by Jim Clark at the Nürburgring . Clark led the field until being overcome by exhaust fumes. Twin Cam made several appearances in Formula 1 in
6230-582: The same frame design as the 1960s original. Powered by Lotus-Ford Twin Cam or its Cosworth derivatives mostly mated to Hewland Mk.8 or Mk.9, it was built by Xanthos Sports Cars in Liverpool, a UK company owned by Lotus specialist Kelvin Jones. Xanthos cars is now based in Niagara falls Canada, and can still supply turn key cars and parts Following the success of his Ultima GTR project, Lee Noble created
6319-406: The scene for the entire 1962 event supporting and winning the 1.3 litre GT class and the Index of Performance prize by a Lotus Elite driven by David Hobbs and Frank Gardner . ACO officials then made the situation worse in admitting a mistake, offering a financial compensation for the 23 entries after the race. With pro-Lotus motoring journalist Gérard Crombac (who reported the entire fiasco in
6408-420: The spare tyre requirement not met. Fitted with a makeshift tall wind screen, all but the spare tyre issue was rectified almost immediately. The original 23 and the later 23B had 4 stud front and 6 stud rear wobbly-web wheels , and carried the narrower and lighter front wheel with its tyre mounted as the spare. (23C had wider 6 stud front and rear wheels.) The French scrutineers argued the requirement to carry
6497-493: The term "four-cylinder engine" is usually synonymous with straight-four engines. When a straight-four engine is installed at an inclined angle (instead of with the cylinders oriented vertically), it is sometimes called a slant-four . Between 2005 and 2008, the proportion of new vehicles sold in the United States with four-cylinder engines rose from 30% to 47%. By the 2020 model year, the share for light-duty vehicles had risen to 59%. A four-stroke straight-four engine always has
6586-413: The top arm at the height of the halfshaft, combined with the outboard disc brakes and coil/damper unit. Unlike the arrangement for Lotus 20 suspension, the halfshafts had Metalastic rubber 'doughnuts' on the inside, carrying no cornering (side) forces. The side forces are carried by the lower wishbone, together with the top 'I' arm link, which connects the tail end of the upper side tube in the frame with
6675-512: The top half of the wheels on the outside) cut-out to expose the entire tyre/wheel in the side view. Lotus 23 proved a competitive, durable, and popular race car. These cars are still a mainstay of vintage racing in Europe and the United States today. Including the 23B and 23C, about 130 examples were made in period, but the popularity of the model led to many additional cars assembled from replacement and reproduction parts. The current estimate on
6764-616: The total number ranges between 200 and 400 excluding Xanthos and Noble . The debut of the 23 was at the Nordschleife on 27 May in the 1962 1000km of Nürburgring . The tiny 100 bhp (70 kW) Lotus 23 with the newly developed Cosworth Mk.X 1.5 litre based on the Lotus TwinCam engine shot away from the field of Aston Martin DBR1 , Ferrari 330LM/GTO , Ferrari Dino 246SP , Porsche 718WRS and others with Jim Clark at
6853-412: The water pump and the camshaft drive chain . After the initial design was finished, outside consultant Richard Ansdale produced detailed drawings of the new cylinder head. Lotus employee Steve Sanville headed the production engineering team that included Mike Costin , Neil Francis and Bob Dance. Harry Weslake conducted a flow bench analysis on the early head. Early Twin Cam prototypes had problems at
6942-517: The wheel in the rain. Even though some cars had almost four times the power of the Lotus, Clark was 27 seconds ahead of Dan Gurney 's Porsche 718GTR after the first lap in the wet. Extending his lead on each lap until the track dried, Clark was overcome by exhaust fumes from a damaged exhaust manifold on lap 12 and crashed out in the 44 lap race. Another 23 with a 997cc pushrod Cosworth Mk.III driven by Peter Ashdown and Bruce Johnstone also attended this race, entered by Ian Walker Racing , and won
7031-484: The world championship in 1983. The 1986 version of the engine was said to produce about 1,300 hp (969 kW) in qualifying trim. Belgian arms manufacturer FN Herstal , which had been making motorcycles since 1901, began producing the first motorcycles with inline-fours in 1905. The FN Four had its engine mounted upright with the crankshaft longitudinal . Other manufacturers that used this layout included Pierce , Henderson , Ace , Cleveland , and Indian in
7120-616: Was at about this time that a Register was established for the Lotus 23. That Register is now part of the Historic Lotus Register of the UK. Some race organizers and the Historic Motor Sports Association began in 2007 to take steps to restrict race participation by replica cars. There are several sources of replicas of Lotus 23 cars. The Xanthos 23 (1999) is an exact reproduction of the 23B using
7209-456: Was designed by Colin Chapman as a small-displacement sports racing car . Nominally a two-seater, it was purpose-built for FIA Group 4 racing in 1962–1963. Unlike its predecessors Lotus 15 and 17 , the engine was mounted amidship behind the driver in the similar configuration developed on Lotus 19 . To comply with FIA rules, it had a regulation trunk space to the right-rear of the driver,
7298-582: Was designed by a team of Lotus employees, Len Terry , Bob Dance and Keith Duckworth , based on Lotus 23. This design was found to be non-compliant to the 1963 Le Mans regulations, so the frame structure was changed to a steel backbone design familiar to Rédélé 's team at Alpine, and became the Alpine M63 . M64 of 1964 had the original frame designed by Terry, and the French Alpine M63 and M64 could fit British 6-stud Wobbly Web wheels as
7387-418: Was developed into the Mk.XIII for Formula racing with the addition of a Cosworth 12-bolt forged steel crankshaft, Cosworth forged conrods, wilder camshafts and 45DCOE Weber carburetors . The use of the original Ford camshaft as jackshaft is abolished and Cosworth-made jackshaft was installed. Although all Mk.XIII was dry-sump requiring externally-driven scavenge/pressure pumps, this bespoke jackshaft retained
7476-417: Was four individual tubes (also part of the head casting). Exhaust gases were handled either by a cast-iron manifold or a fabricated tubular header, depending on application. The original in-block camshaft was retained and, as in the original 116E, drove the side-mounted distributor and nearby external oil pump/filter assembly, minimizing modifications to the mass-produced iron block. The original cam along with
7565-437: Was invented in 1911 and consists of two shafts carrying identical eccentric weights that rotate in opposite directions at twice the crankshaft's speed. This system was patented by Mitsubishi Motors in the 1970s and has since been used under licence by several other companies. Not all large displacement straight-four engines have used balance shafts, however. Examples of relatively large engines without balance shafts include
7654-688: Was ninth place at the 1965 South African Grand Prix , again in the Willment Brabham. Cosworth Mk.XV powered the Elan 26R of the Willment Team and driver John Miles to 15 seasonal wins and the 1966 Autosport Championship title. Third-party engine builders continued development after 1966 for the Elan and Cortina as well as for Formula 2, 3 and other classes. Early tuners included Holbay , Vegantune, and Novamotor, joined later by Brian Hart , Richardson, Wilcox and others who focused mainly on
7743-515: Was originally designed as a 2 L Formula 2 engine for the Ferrari 500, but evolved to 2.5 L to compete in Formula One in the Ferrari 625. For sports car racing, capacity was increased up to 3.4 L for the Ferrari 860 Monza. The Coventry Climax straight-four engine was also a very successful racing engine, which began life as a 1.5 litre Formula 2 engine. Enlarged to 2.0 litres for Formula One in 1958, it evolved into
7832-404: Was shared with Lotus 22 and other later Lotus formula cars, but the combination of a wider and thus larger radiator, wider and bulkier steel frame acting as a cooling device, and the small displacement engines resulted in more than ample cooling capacity. Atypical of the contemporary racing cars, Lotus 23 models sometimes experienced an over-cooling problem when the thermostat was not installed in
7921-566: Was succeeded by the Lotus 907 engine. For the Lotus Elan , Lotus founder Colin Chapman wanted to find a less expensive engine than the costly all-alloy Coventry Climax FWE used in the original Lotus Elite . He felt that basing his new power-plant on an engine built in large volumes would keep costs down. Chapman initially chose the Ford 105E inline four used in the Ford Anglia as
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