Interesting engines we forgot all about

Some – like the Chevrolet smallblock, the Ford Kent and the Porsche flat six – will probably remain in the public memory for a long time, but others are known today only to people with a particular interest in cars.

Here are 30 examples of the ones gradually being lost to time, listed in alphabetical order. While we’re sure you will know about some of them, congratulations are due if you were already aware of the full set.

It would be easy to mistake this for a Chrysler engine, because it was used long after Chrysler took over the American Motors Corporation in 1987, but it was definitely the work of AMC. The original brief was to produce a unit which would power off-road vehicles, so durability and strong performance were design priorities right from the start.

The 2.5-litre straight four made its debut in Jeeps and the AMC Eagle (pictured) in 1983, and was still being used in the Wrangler SUV and the Dodge Dakota pickup in the early 21st century.

Hardly any British motorists of the 1920s and 1930s – and indeed very few pedestrians – would have been unaware of the Austin Seven, which at one point even had a song written about it. The little car was exceptionally popular, and its four-cylinder engine (usually though not always measuring 747cc) was both economical in its standard form and capable of being tuned to produce remarkable amounts of power, especially when supercharged.

More than 80 years after the Seven was discontinued, there’s very little reason why a non-enthusiast should know about it, but there are plenty of these cars and their derivatives still around if you know where to look.

If it had a more evocative name than M10, this engine might be much better known than it is. Available in capacities from 1.5 to 2.0 litres, it was first used in the New Class saloons in 1962, and was still around more than a quarter of a century later.

In its most extreme form, it powered the celebrated BMW 2002 Turbo (pictured), and was also the basis of the S14 used in the first-generation BMW M3 and the turbocharged 1.5-litre M12 Formula 1 engine which, with the boost turned up in qualifying sessions, was estimated to produce around 1400bhp.

While it’s probably best known for its fours and sixes, BMW has also ventured into V8 and V12 territory. Its earliest V8 is also the only one described as overhead-valve (meaning that the valves are above the pistons but the camshaft is alongside them), and the reason you probably aren’t aware of it is that it hasn’t been used since 1965.

It had made its debut in 2.6-litre form 11 years earlier in the 502 saloon (pictured), and would later be expanded to 3.2 litres. Among other vehicles, it powered the fabulous, but also very unsuccessful, 507 sports car of the mid to late 1950s.

‘90-degree’ refers to the angle between the two banks of cylinders in this engine. It’s not ideal for a V6 (60 or 120 degrees would be more suitable) and therefore seems an odd choice for Chevrolet to make, until you discover that the engine was actually an abbreviated version of the smallblock V8.

The smallblock was already more than 20 years old when the V6 made its debut in 1978. It was fitted to a wide variety of GM vehicles, from pickup trucks to the Chevy Camaro. In turbocharged 4.3-litre form, it also powered the very fast, and now quite rare, high-performance GMC Typhoon SUV (pictured) and Syclone pickup.

‘Poly’ here refers to the polyspheric shape of this V8’s combustion chambers, as opposed to the hemispheric ones in what would become known as the first-generation Chrysler Hemi. Introduced in 1955, this engine, available in capacities from 4.0 to 5.8 litres, was less efficient than the Hemi but much cheaper to build, which made it a reasonable choice for the low-cost Plymouth brand.

Chryslers would later receive the Poly too, but the engine was soon superseded by one known simply as the A, and was never fitted to anything after 1958.

(PICTURE: 1956 Plymouth Belvedere convertible)

This straight six engine is said to have been canted over at an angle of 30 degrees so that it would fit under the bonnet of the 1960 Valiant (later branded as a Plymouth), and was never mounted upright in anything else due to the cost of conversion.

Measuring 2.8, 3.2 or 3.7 litres, it was used in many Chrysler, Dodges and Plymouths into the 1980s without ever causing much excitement, except when fitted with the option Hyper Pak which improved its performance greatly.

(PICTURE: 1966 Plymouth Valiant)

The Citroën 2CV and its various derivatives were famously powered by an air-cooled flat twin engine, but it’s less well remembered that the company also produced a similar but larger flat four. Available in capacities from 1.0 to 1.3 litres, it was used in the ingenious GS introduced in 1970 (pictured), and later renamed GSA, and in the Ami Super.

These cars do not figure highly in motoring life today, but they are probably better remembered in most countries than the Romanian Oitcit Club, which had the same engine.

It’s a strange quirk of Citroën history that two of its most innovative models had engines which hardly anyone talks about. The Traction Avant of 1934 was usually fitted a with a four-cylinder motor, measuring up to 1.9 litres, but that fact tends to get swamped in discussion about its low-slung body and the then radical feature of front-wheel drive.

The same engine was later reworked for the brilliant DS (pictured) and its lower-budget equivalent, the ID, but people inevitably prefer to discuss its remarkable aerodynamics, fantastic appearance and hydropneumatic suspension rather than the bit that makes the noise.

The engine derived by Rover from a Buick design is easily the longest-lived and most common smallblock British V8, and has completely eclipsed the slightly earlier unit of the same layout produced by Daimler.

This was used from 1959 in the SP250 sports car, but far more frequently in the 2.5 V8 saloon, a version of the six-cylinder Mk2 produced by Daimler’s then owner, Jaguar. Like the same brand’s 4.5-litre V8 of the same period, it was canned when Jaguar, and therefore also Daimler, became part of the new British Leyland Motor Corporation in 1968.Unfair, as it was a smooth and sweet unit that deserved a longer life.

By reducing the cylinder bore of its 2.9-litre Dino V8 engine, Ferrari brought the capacity down to just under 2.0 litres in 1975. Performance naturally suffered, but with this engine installed the Dino GT4 became much cheaper to tax in Italy, and therefore more appealing to less wealthy Ferrari aspirants.

The same engine was used for the same reason in the 208 GTB and GTS from 1980. Two years later, it was turbocharged, leading to a substantial increase in power from the previous 153bhp to 217bhp.

If ever an engine was hidden in plain sight, it was the 100 Series. The little four-cylinder unit – so unassuming that you might never have been aware of it until now – made its debut in the Fiat 600 in 1955, and went on to be used, in capacities from 0.6 to 1.0 litres, in a quite staggering number of other small Fiats, as well as in Autobianchis, Lancias, Seats and Yugos.

Strictly speaking, it was replaced in 1985 by the Fully Integrated Robotised Engine (FIRE), but it continued to be churned out for many years after that.

The term Ford sidevalve applies to two engines of very similar design measuring 933cc and 1172cc respectively, and introduced, in that order, in the 1932 Model Y (pictured) and the 1934 Model C. It was still appearing in British Fords in the early 1960s, and was also used in cars produced by the then separate Ford of Germany.

The larger version was the basis of the 1172 Formula racing class, and powered a great many specialist sports and competition cars.

Including the one fitted to the Model K in 1906, the Thriftpower was the fourth of Ford’s straight six engines. Like the Fiat 100 Series, it doesn’t have a particularly special place in motoring history, but it was certainly used widely.

Initially appearing in the 1960 Falcon (hence its alternative name, Falcon six), it was available in capacities ranging from 2.4 to 4.1 litres and survived into the early 1980s, having on several occasions even served as a much less exciting alternative to V8s of one kind or another in the Mustang.

You get two engines for the price of one here, because both Ford of Britain and Ford of Germany produced V4 engines (a layout now no longer used in any car) in the 1960s and 1970s. The German one (pictured inset), known either as Taunus or Cologne, was the smaller of the two, with capacities from 1.2 to 1.7 litres, and was fitted in many locally-built Fords, as well as in several Saabs, the Matra 530 sports car and, oddly enough, the Mustang I concept of 1962.

The Essex V4, measuring either 1.7 or 2.0 litres, first appeared in the Corsair (pictured) and the Transit van in 1965, and would later be used in the Capri and Granada.

A relatively short production life of 10 years means that the Y-Block is one of the less famous of the classic Ford V8 engines. The replacement for the Flathead was introduced in 1954, and was used in many cars and trucks – including the first-generation Thunderbird (pictured) – with capacities ranging from 3.9 to 5.1 litres.

The second of those figures seemed increasingly inadequate for an American V8 as the years went on, and that partly explains why Ford developed the smallblock Windsor and the big block FE, both of which could be made significantly larger.

Ford’s involvement with V4 engines was far shorter than that of Lancia, which persevered with the now largely abandoned layout for more than half a century. There were many Lancia V4s over the years, but they were all characterised by a remarkably narrow angle between the two banks of cylinders.

The last Lancia V4 was used in the Fulvia Coupe, one of the most successful rally cars in the world in the late 1960s and early 1970s.

Wankel rotary engines have occasionally had just a single rotor, but more often two. Even experts in the subject may need reminding that Mazda (by far the manufacturer most loyal to this ingenious but problematic type of engine) once created a road car which had three rotors.

It was branded not as a Mazda but as the Eunos Cosmo. Produced from 1990 to 1996, this premium coupe was also well ahead of the game due to its built-in satellite navigation system, but that additional piece of trivia seems to have been largely forgotten too.

Not greatly celebrated even when it was in production (because, to be fair, it didn’t need to be), the M111 was the ‘bread and butter’ Mercedes four-cylinder petrol engine for most of the 1990s and into the early 21st century. Measuring anything from 1.8 to 2.3 litres, it was used in most Mercedes models from the C-Class upwards, and also in several South Korean SsangYongs.

The M111 was at its most interesting when supercharged, as it was in cars whose names included the letter K, standing for Kompressor.

CIH stands for ‘cam in head’, a reference to the fact that although the camshaft was mounted above the cylinders rather alongside them, it was still operated by pushrods. The CIH family included both four- and six-cylinder engines, and first appeared in the Opel Rekord in 1965.

The most memorable CIH units were the 2.4-litre four used in the Ascona 400 and Manta 400 homologation specials, which were successful in rallying, and the twin-turbo 3.6-litre six which contributed so positively to the reputation of the car known in the UK as the Vauxhall Lotus Carlton (pictured) and in other markets as the Opel Lotus Omega.

Asked to name a French air-cooled flat twin engine, most motoring enthusiasts would probably think first of the one used in the Citroën 2CV. Hardly anyone’s mind would jump immediately to Panhard, but this much smaller, and now long gone, company specialised in exactly that type of motor from 1945 until its absorption into – strangely enough – Citroën in 1967.

The same basic engine was used first in the very quirky Panhard Dyna X and finally in the far more elegant Panhard 24 (pictured), and measured between 610cc and 851cc depending on which model it was fitted to.

The 2.0-litre B engine was Saab’s 1972 redesign of the Triumph slant four, which had been fitted to the Saab 99 saloon since 1968. It was redesigned again to become the H in 1981, but throughout the 1970s it was Saab’s premier engine, powering the 99 and larger 900 while the 96 made do with the V4 unit imported from Ford.

The most famous B, and probably the one best remembered today, was the forced-induction version which, as fitted to the 99 Turbo, was largely responsible for bringing the terms ‘turbocharger’ and, less happily, ‘turbo lag’ into everyday conversation.

Most people who know about Saab’s history are aware that the Swedish company bought in the German Ford V4 engine to replace its own three-cylinder two-stroke in 1967.

Less well remembered is that the latter was actually Saab’s second engine, the first being a two-cylinder unit used only in the 92, which went into production in 1949.

The twin had a capacity of 764cc and was therefore slightly larger than the first version of the triple, which measured just 748cc. The situation was reversed when the triple was expanded to 841cc during the lifetime of the 96.

Named after the French town where Simca had a factory (and Stellantis still does), the Poissy was a small four-cylinder engine which first appeared in 1961, mounted in the rear of the Simca 1000 (pictured). It went on to be used in many other vehicles, including the Simca 1100 and Simca 1307, the latter known in the UK as the Chrysler Alpine.

The 1307/Alpine was launched after Simca had become part of Chrysler Europe. This was taken over by Peugeot in 1978, which led to the Poissy being used in some Peugeot models up to around 1990.

Between the two World Wars, the British Trojan company produced thousands of cars and trucks powered by one of the strangest engines ever invented. The horizontal four-cylinder two-stroke unit was mounted underneath the seats, and could work only if the conrods flexed during operation, something which would normally lead to immediate disappointment. Very little power was produced, but the engine was almost unburstable, as savage destruction tests are reputed to have shown.

The engine was also so economical that Trojan was able to claim in its ads that driving one of its cars for 200 miles would be cheaper than walking the same distance. Despite this splendid piece of marketing, the rest of the motor industry completed ignored the design, and has not come up with anything remotely like it.

In 1908, the year he turned 25, Laurence Pomeroy (1883-1941) took advantage of the fact that his boss was on holiday in Egypt and single-handedly designed a brilliant 3.0-litre four-cylinder engine. Astonishingly powerful for its size and time, it was first used in the Vauxhall A-Type, and was reworked for later models including the famous 30-98.

It’s now largely forgotten simply because it was created so long ago, but that doesn’t alter the fact that Vauxhall and its young engineer once produced an absolute marvel.

The cylinders in this engine were inclined 45 degrees from the vertical, partly to reduce height and partly because of plans to double it up into a V8 version, which in fact never made production. Even in its original form, though, the slant four performed well in a large number of vehicles, starting with the 1967 Vauxhall Victor (pictured) and including the Bedford CF van.

The most famous version was the 2.3-litre twin-cam used in the Chevette HS and HSR, both of which performed well in international rallying in the late 1970s and early 1980s.

A small number of fourth-generation Volkswagen Passats were fitted with a very unusual W8 engine. This was created by mounting two narrow-angle V4 engines on a common crankcase, producing a unit which, though wide, was very short, and therefore easy to fit if mounted longitudinally.

The Passat W8 was produced from 2001 to 2004. The next-generation model had its engine mounted transversely, which made the W8 completely unsuitable. Volkswagen, having been the first manufacturer to attempt the layout, has not returned to it since then, and nobody else has tried it either.

The 1.8-litre B18 launched in 1961 and its slightly later 2.0-litre B20 derivative were exceptionally strong, though otherwise unremarkable, engines which simply got on with the job they were supposed to do without fuss, in a very Volvo-like way.

As a result, they are not well remembered today, but one example of the B18 is, ironically, one of the most famous engines in the world. It was fitted to the Volvo 1800S which schoolteacher Irv Gordon (1941-2018, pictured) drove for 3.2 million miles, a world record for a privately owned car.