Lotus 43: F1’s only 16-cylinder race-winner

2015 Goodwood Festival of Speed

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Today’s V6 hybrid turbos are rubbish, right? The V8s were much better.

Actually, no, the V8s were a bit pants. Now the V10s which preceded them, those were the real deal.

Taking this flawed logic to extreme, the ultimate in Formula One car technology might well be this: the only car to win a round of the world championship using a 16-cylinder engine.

Strange, you might think, to dedicate an entry to a car which only appeared in five Grands Prix.

Unusual too, that what makes this Lotus particularly interesting is not some technical wizardry pioneered by Colin Chapman, but its engine.

The Lotus 43 was the car that gave BRM’s unorthodox Type 75 H16 engine its only Grand Prix victory, in Jim Clark’s hands in the 1966 United States Grand Prix.

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The 16-cylinder beast was conceived in 1966 as a means of producing an power plant for F1’s new engine rules. After the 1965 season engine capacities were doubled from one-and-a-half litres to three.

BRM’s notionally simple solution was to bolt together the cylinder banks from two of its successful 1.5-litre V8 engines in an H-pattern to create a single 3-litre unit. The engine, designed by Tony Rudd, was raced by their factory team using its P83 chassis in 1966, and was also supplied to Lotus.

The Lotus 43 was based on the 38 which Clark had used to win the Indianapolis 500 the year before. The front portion of the car was much the same, behind which the H16 was bolted directly to the chassis and the rear suspension fixed to the engine.

This was an early example of an engine being used as a stressed member in an F1 car. It pre-dated the use of the engine this way in Colin Chapman’s Lotus 49, which is often credited with being the car which pioneered this approach with its Cosworth DFV engine*.

The enormous dimensions of the H16 practically forced Lotus 43 designer Maurice Philippe incorporate it as part of the chassis.

With two pairs of engine banks stacked on top of each other, the lower banks requiring exhausts that exited beneath them, the engine was cursed with an unappealling combination of high weight, a poor power-to-weight ratio, and a high centre of gravity.

Taken together the engine, gearbox and clutch tipped the scales at a whopping 305kg. This was the antithesis of the Chapman mantra: ‘simplify and add lightness’.

It did, however, produce one of the most dramatic and distinctive engine notes ever to wail from the back of an F1 car.

BRM and Lotus struggled with dire unreliability to begin with in 1966. So much so that the engine was not seen for a few races mid-season while work was done to improve the transmission.

At its return Clark showed a flash of promise in the Italian Grand Prix, running quickly when all 16 cylinders were firing properly, until the gearbox died ten laps from home.

At Watkins Glen the car ran well in practice and Clark took second on the grid. But his engine failed late in practice, prompting BRM to give Lotus their spare. The work to reattach engine to car went on up until the final moments before the start was given. Meanwhile Clark prepared to jump into the team’s spare car, with its Coventry-Climax two-litre V8, if the work wasn’t finished.

Clark ran in fourth place in the early stages. For all its weight and complexity the H16 was estimated to be producing little more than 375bhp. But for once it was his rivals who hit trouble.

John Surtees tangled with Peter Arudell while lapping the Lotus driver. Next Lorenzo Bandini’s Ferrari and Jack Brabham, driving his own car, suffered engine trouble.

That promoted Clark into the lead. Against expectations, the glorious cacophony from his 16 cylinders never faded, and after 108 laps he crossed the line to score a historic win.

This was the one and only time Lotus’s H16-engined car finished a race. It appeared twice more: in the season finale in Mexico, and at the first race of 1967 in South Africa. After that it was replaced by a car and engine with half as many cylinders which enjoyed vastly more success: the Lotus 49 with its Ford-Cosworth DFV V8.

The best BRM managed to do with their own engine was second place for Jackie Stewart at Spa later that year.

Though it had become a race-winner, BRM’s H16 engine was not the future of F1 engine power. But the 16-cylinder monster deserves its place in F1 history as a tremendous and idiosyncratic creation, though one that probably would never have won a race without the genius and mechanical sympathy of Clark.

Pictures: Lotus 43-BRM H16 at the 2015 Goodwood Festival of Speed

*There were other, earlier F1 cars which also used the engine in this way, not least BRM’s P83 mentioned above.

According to automotive historian Karl Ludvigsen (in his books Colin Chapman: Inside the Innovator and Ferrari: 60 Years of Technological Innovation), the first team to do this in F1 were Ferrari, with their 158 V8 which made its debut in 1964, with which Ferrari won the constructors’ championship.

Ferrari developed the concept after seeing how Vittorio Jano’s Lancia D50 incorporated the engine as a partly-stressed member, when they took over the cars and raced them from 1955.

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Keith Collantine
Lifelong motor sport fan Keith set up RaceFans in 2005 - when it was originally called F1 Fanatic. Having previously worked as a motoring...

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6 comments on “Lotus 43: F1’s only 16-cylinder race-winner”

  1. Ok, I wasn’t jealous until now. Not every day you get to hear the H16 in the flesh :)

  2. Keith Crossley
    28th June 2015, 15:54

    Thanks for bringing some memories (almost 50 years!) back with this.

    Have you ever tried to sleep the night in a bugeye Sprite; my brother and I tried that at the Glen the night before USGP 1966. I’d been a big Clark fan since 1962 but didn’t have a lot of hope considering how the season was going for Brabham. Obviously we were delighted when Jim inherited the lead and won!

  3. I think at that race that Clark’s car was being topped up by oil pretty much up to the point where today everyone leaves the grid.. while Surtees made up a lap after losing many berating Arundell in the pits and Clark got the car to the finish!

  4. I love the heroic complexity of the engine and the beautiful simplicity of chassis, form absolutely following function, an air intake just big enough to cool the engine, bodywork tapering up to a cockpit just big enough for the driver, no wings, no widgets, and the mechanicals on display for all to see. Truly a “Golden age”.

    1. well said, and while a touch to the nostalgic, it does point to a good thing many would like to see more of @hohum – i.e. show off more of what is going on “under the hood” hiding less in uncompromisable acronyms and behind bodywork and garage doors.
      It also is the opposite of “gimmicks” because this car truly was a compromise of just how to fit the needed bits together (engine – bolted, exhausts – present, inlet – yes, its there, driver – put him in between) and make it work enough to make it to the line in the hands of a great driver paired with a good dose of some luck.

  5. Yes, this engine, together with how it came to be there belongs firmly in the sport’s history.

    A great engine for it shows how the engineers came to this solution: hey, we can go 2 x as big, so lets bolt 2 blocks together. The other way has been used many times too off course (cutting off cylinder banks to go from V10 to V8 etc, halving the engine from V12 to V6+Turbo etc). It also nicely shows the shortcomings of that approach compared to making a new unit that is designed to fit (the Cosworth DFV V8).

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