Why car firms use other people's engines - and does it matter?

It sounded terrible and had serious early reliability issues. Ever since, Lotus has sensibly relied on OPE.

It is quite remarkable what can be done with engines sourced from elsewhere. Drive a Lotus Evora 400 and you might struggle to associate the growling monster in the engine bay with a motor that started life in a Toyota Camry. If you were lucky enough to grab a ride in the Noble M600, you might find it even more fanciful that the 600bhp motor and its ability to apparently puncture time itself was more usually found under the bonnet of an old Volvo XC90 SUV. It’s not what you’ve got, it’s what you do with it that counts.

Years back, a few of us spent a weekend building a Caterham Seven for a feature, powered by the well-known ‘red top’ 2.0-litre Vauxhall engine designed for Cavaliers and Calibras. But installed in a car weighing the same as a tube of toothpaste, with a pair of 45mm Weber carbs strapped to one side as close to a straight-through exhaust as was possible on the other, it turned into a rampaging maniac of a motor without the smallest modification required inside. 

Of course, sometimes the OPE approach can go too far. In 1998, Jaguar showed the XJ220 supercar, powered by its own V12 engine topped by four-valve heads. People made wealthy by the hard-charging bull market of the era formed an orderly queue. Spool forward four years to 1992, when the production version arrived, and the world was in a far less rosy economic place. And the V12? It appeared to have halved in size. In fact, the new 3.5-litre V6 engine had been sourced from a Metro. Yes, it was quite a special Metro – the 6R4 rally car – and had already done great work powering Jaguar’s own Group C cars, but those looking to bail out of a commitment made in different times used the engine swap as an ideal excuse to do exactly that. Acrimony was to follow. 

But then there are times when the other thing happens, when a completely unremarkable car gets transformed by another person’s engine. The best example I can think of is the Lancia Thema 8.32, which was built on the same platform as the Fiat Croma and Saab 9000 but powered by an engine from Ferrari. Actually, it was better even than that: to make it more suited to a saloon application, Ferrari fitted a crankshaft that fired at 90deg rather than 180deg intervals, so it sounded like it could have been designed in Detroit. It is, to date, the only Ferrari V8 configured in this traditional way rather than as, in effect, two four-cylinder engines on a common crank. 

Yet of all OPEs, and talking of Detroit, the Americans have made more than everyone else put together. Without the Ford V8, there would have been no AC Cobra, nor any De Tomasos. Bristol and Jensen were entirely dependent on Chrysler motors, and more start-up supercar companies relied on General Motors’ big and small-block powertrains than all the others put together. Powerful, affordable, reliable and available, the ubiquitous ‘Chevy V8’ is the ultimate example of the OPE. 

What’s more, we should expect the use of other people’s engines to increase. Such are the emissions regulations these days that it is now more difficult and expensive to design a brand-new engine today than ever before. It is to its eternal credit that Ferrari still does, but this is a brand defined in large part by its engines. For almost every other low-volume producer, OPEs aren't just convenient; they are life-saving. 

The greatest racing OPE

The Ford Cosworth DFV reigns supreme and this year celebrates its 50th anniversary. Best known for its Formula 1 applications, where it won 12 out of 15 drivers' titles between 1968 and 1982 and at its mid-1970s peak powered often every single car on the grid save a pair of Ferraris, the engine and its derivations were far more successful even than that.

 In turbocharged guise, it won 10 Indy 500s and crowned nine Indy champions, it won Le Mans twice in the back of sportscars and, as recently as 2001, helped Bentley back to Le Mans by powering the development prototype before Audi engines were available. Once, it even powered a Transit van, as those who recall Supervan 2 from the 1980s will recall. 

The weirdest uses of OPEs

1. Aircraft engines have been used in all sorts of cars – but very rarely in road cars. One of the more notable exceptions was ‘The Beast’, created by John Dodd in the 1970s and powered by a 27-litre Rolls-Royce Merlin engine. Credited with a 1000bhp output and capable of just 2mpg, it was listed by the Guinness Book of Records as the most powerful road car in existence.