How BRM’s engine overreach hindered a pioneering F1 Lotus

In the pantheon of great Lotus racing cars – and there were plenty of them – there is no pedestal reserved for the 43, despite its status as a grand prix winner. Indeed, earlier this year GP Racing’s sister magazine Autosport placed it third in a list of the 10 worst GP-winning racers. Rather a harsh judgement on a car which had so much in common with its successor, the seminal 49, including the then-radical use of the engine as a stressed element of the chassis – it’s just that there’s no getting past the reputation of that engine.

PLUS: Track testing the legendary Lotus 49

There’s a popular dictum among engineers that there’s no such thing as a problem, merely a solution waiting to be found. When Formula 1 made its much-vaunted ‘return to power’ in 1966 it left teams and manufacturers scrambling for any answer within reach – and BRM’s proposition arrived with a container load of further solutions required. But Lotus, freshly in receipt of the 1965 drivers’ and constructors’ championships, desperately needed an engine for the new 3-litre era.

You might wonder why the team which finished second in the 1965 constructors’ standings (and actually outscored Lotus, but only the best six results counted for the championship) should contemplate supplying a direct competitor. The answer lies in the complicated and rapidly changing picture of engine politics in the mid-1960s.

F1 wasn’t the globe-straddling mega-category it is today – sportscar racing was arguably more lucrative in terms of prize money. Aside from Ferrari, BRM and the recently arrived Honda, the only engines competitive at this level came from the workshops of Coventry Climax – and it had already signalled its intention to get out of the motor racing business even before its acquisition by Jaguar in late 1965.

Lotus founder Colin Chapman spent much of 1965 chasing options for the following season. Bob King’s Racing Preparations Ltd – later to make junior single-seaters under the Royale name – acquired Coventry Climax’s spares inventory, intellectual property and some of the tooling but the venerable FPF four-pot couldn’t be stretched to three litres. Supercharging the 1.5-litre FWMV was too risky from a financial point of view.

Coventry Climax had abandoned development of a 1.5-litre flat-16 which might also have been responsive to supercharging. Chapman went looking elsewhere, reached a landmark agreement with Walter Hayes and the Ford Motor Company to underwrite development of a new naturally aspirated, Cosworth-designed 3-litre V8, but this wouldn’t be ready until 1967 at the earliest. 

Photo by: James Mann

Joining forces with BRM was understandable given the options Chapman faced, but proved a mistake

Meanwhile in Bourne, BRM had come close to breaking even on racing activities in 1965 thanks to supplier deals in F1 and F2. Parent group Rubery Owen was feeling the pinch as the British car industry it supplied slid towards the doldrums; company proprietor Sir Alfred Owen sniffed an opportunity to actually turn a profit with BRM.

In his autobiography It Was Fun, chief engineer Tony Rudd described a meeting in which Chapman silkily charmed Sir Alfred, who closed proceedings sure in the knowledge that BRM’s new engine must be best-in-class if the great Chapman was so desperate to bolt it into one of his serial championship-winning cars – and, indeed, would like an even bigger one with which to compete at Indianapolis.

But even great engineers have their particular follies and the H16 would prove to be one of the highly respected Rudd’s
least successful projects. Bedevilled by development obstacles and cost over-runs, it never achieved the two key parameters set out for it. As racing historian Karl Ludvigsen put it in his book Classic Racing Engines, “Estimates were that it would weigh 380lbs and produce 500bhp – figures which, in the event, were destined to be interchanged.”

Posterity enshrines this as yet another over-reach by a team with a reputation for mingling buccaneering engineering with occasionally slapdash organisation

Rather than scaling up BRM’s existing 1.5-litre V8 architecture, Rudd believed more potential could be unlocked – and a higher rev ceiling achieved – with a 16-cylinder engine. Since this would have been too long as a ‘vee’, he arrived at the ‘H’ format: in effect two of the 1.5-litre V8s with the vee flattened out, one on top of the other, with their crankshafts geared together and sharing a common case.

Posterity enshrines this as yet another over-reach by a team with a reputation for mingling buccaneering engineering with occasionally slapdash organisation (in 1960s, drivers Graham Hill and Dan Gurney had threatened to go on strike unless Rudd was given more authority over team operations).

But in the context of the era it was an exciting new example of the aeronautical influence sweeping through motor racing, a phenomenon which had elevated grand prix cars from crude ladder-frame chassis with bolt-on bodywork to stressed-skin, aero-bodied missiles. In World War II, Napier & Sons had developed the H24 Sabre engine for use in Hawker Tempest and Typhoon fighters so this configuration wasn’t without precedent – though Rudd could perhaps have done more due diligence on the Sabre’s troubled journey to production…

Although its cylinder banks were horizontally opposed,
the H24 wasn’t a ’boxer’ engine in which the opposing pistons
have individual crankpins and move inwards and outwards
at the same time; it remained, essentially, like two flattened
out vee engines uneasily cohabiting with shared facilities.
The vibrations were immense, the gearing fragile.

Photo by: James Mann

The overweight and unreliable engine rendered the 43 an ineffective car

When parts broke under duress during development, they were replaced with stronger (and, therefore, heavier) equivalents until they stopped breaking. The plan to have three camshafts on each side, with the central one actuating the inlet valves of both cylinder banks, had to be shelved when the port angles this set-up required were sub-optimal for combustion.

Moving to twin-cam heads added weight, complexity and internal friction as well as raising the centre of gravity – and incurring a delay of several months while BRM optimised design and materials. As a result, the weight of the new engine ballooned far beyond initial estimates.

As Rudd recalled, “We delivered an engine and gearbox to Lotus which nearly destroyed the small van they sent to fetch it. They were absolutely thunderstruck by its weight. With all the modifications the engine weighed 555lbs [252kg] plus 118lb [53.5kg] of gearbox and clutch.” Cosworth’s V8, when it was ready, came in at 166kg.

Maurice Phillippe, recently installed as Lotus chief designer after Len Terry’s departure, was horrified. But among the H16’s mitigating features was the facility to use that much-strengthened block as a structural element of the chassis, with the rear suspension bearing off it and the gearbox. Popular F1 history anoints Phillippe’s Lotus 49 as the first GP car to use the engine as a fully stressed element of the chassis but his 43 design predated this by a year; in any case Ferrari’s Mauro Forghieri had got there first, with his 12-cylinder 1512 in 1964.

The Type 43 monocoque was based on Terry’s Type 38 Indycar design, a fully enclosed shape rather than a ‘bathtub’ type which would typically feature cosmetic body panels on top, trading stiffness for ease of access. Suspension followed similar layout and geometry to the Lotus 33 Clark had campaigned with such success in the 1.5-litre era. Concerned by the effect of turbulence induced by the rear wheels, Chapman and Phillippe installed small fairings on each side of the engine to encourage cleaner airflow to the H16’s induction trumpets.

Peter Arundell, returning to action after a long injury lay-off, was the guinea pig at Lotus as Jim Clark began the season in a Type 33 powered by a Coventry Climax V8 Chapman had persuaded the company to extend to two litres. At the first round, in Monaco, Arundell was a late withdrawal because the H16 didn’t arrive; BRM had one for works drivers Graham Hill and Jackie Stewart to evaluate in practice but it was deemed too new to race.

Clark set pole, while Stewart won in his 1965 car fitted with a 2-litre engine, but the rest of the season would be dominated by Jack Brabham’s team with its Repco-fettled V8, the only competitive 3-litre in 1966. Budget constraints prompted Ferrari to run a sportscar-derived V12 which enraged John Surtees and set him on a path to walking out mid-season.

PLUS: How Surtees became an unappreciated Ferrari great

Photo by: David Phipps

Arundell was Lotus's guinea pig with the three litre BRM H16 engine which scuppered his season

In Belgium Arundell didn’t even get as far as practicing in his 43, when a distributor drive gear sheared on his way out of the paddock. Three weeks later, in early July, at the final French GP to be held at Reims, Arundell burned his clutch out after taking off in the wrong gear during practice, and qualified at the back of the grid. In the race he managed three laps with the car continuously jumping out of gear before retiring. 

The works BRM drivers had also been troubled by the truculent six-speed ’box. Chapman identified the problem as a design fault which caused the hydraulically operated clutch to accelerate rather than slowing down during shifts, damaging the gear engagement mechanism.

Two more months and three championship grands prix would pass while BRM redesigned its gearbox and political pressure built within the company to get the 3-litre engine out there again as soon as possible, since Brabham – now an OBE – was clearing up in the title race. On the weekend Brabham’s gong was announced, Stewart joked that he and Hill deserved a similar honour for persisting with the H16. 

Only after an all-nighter and working well into the day did the Lotus mechanics finish the engine change - with minutes remaining until Clark had to take his place in second on the grid

For the Italian GP at the beginning of September, BRM arrived with a gearbox fix and introduced a new engine into the works pool with a revised timing mechanism enabling it to fire cylinders individually rather than two at once. But neither of the factory entries got as far into the race as Clark, racing the 43 for the first time (and somewhat grudgingly, having spent some of practice lapping in the Climax-engined Lotus entered for Italian pay driver Giacomo ‘Geki’ Russo).

From third on the grid Clark made a slow getaway,
distracted at the crucial moment by a jittery fuel pressure reading. As Clark began a spectacular fight back towards the leaders, Hill’s engine – the new one – failed on the opening lap. Clark reached fifth before vibrations from a partially deflated rear tyre sent him into the pits. Battery issues stymied him thereafter and, after another pitstop to examine the electrics, he stopped for good at the end of the 58th lap, the car stuck in gear. Still it was 53 more laps than Stewart, who halted with a fuel leak.

At the end of September the grand prix field reassembled in upstate New York for the US GP at Watkins Glen, where the promoter had instituted a new prize system in the hope of capturing the general public’s imagination. Rather than the customary system of individually negotiating ‘starting money’ with teams – in effect an appearance fee based on box office value – the Watkins Glen Grand Prix Corporation was offering a prize purse totalling more than $100,000, on a sliding scale with the winner taking $20,000. Chicken feed by modern standards but, in period, a veritable jackpot.

Chapman initially entered Arundell in the 43 but Clark drove it briefly in practice before reverting to his own Climax-engined car – which was frustratingly slow before it stuck in gear. The stars aligned: Clark got back in the 43 and squeezed it for a lap time a tenth off polesitter Brabham. Chapman was overjoyed – until Clark reappeared from his slow-down lap with oil leaking from one exhaust bank. The engine had eaten itself again.

Photo by: Rainer W. Schlegelmilch / Motorsport Images

Clark was reluctant to race the 43 with its hefty BRM engine and his concerns were underlined at Monza

For PR purposes BRM ‘lent’ Lotus a spare H16 lump which had already seen plenty of action (according to Ludvigsen, the block was patched with metal plates and epoxy resin). Only after an all-nighter and working well into the day did the Lotus mechanics, led by Dick Scammell, finish the engine change – with minutes remaining until Clark had to take his place in second on the grid. Even then Scammell had to twiddle the spanners quickly once more to rectify an oil leak.

A substantial crowd – boosted by interest in John Frankenheimer’s Grand Prix movie, which had been filming throughout the season – watched enthralled as Ferrari’s Lorenzo Bandini vaulted into an immediate lead, chased by Clark and Brabham. Surtees, now in a Cooper after his Ferrari uncoupling, pipped Clark for third but came unstuck as the leaders came up to lap Arundell in the Climax-engined Lotus.

Brabham, now in the lead, got by, as did Bandini, but Arundell was less accommodating with Surtees and the pair ended up gyrating across the grass in the Esses. Both drivers pulled into the pits and stopped in Lotus’s area: ‘Big John’ was on a mission to remonstrate with the Lotus number two.

Had Surtees not succumbed to the red mist he might conceivably have won the race, for he restarted in 13th and fought back to third at the flag, gaining a lap back on Clark in the process. Brabham and Bandini had both dropped out with engine failure around half distance, leaving a surprised Clark not only in the lead, but also in a position to baby the H16 to the flag as second-placed Jochen Rindt ran out of fuel.

PLUS: Jim Clark's top 10 best drives

Normal service was resumed in Mexico when the Glen-winning engine underwent what modern engineers call ‘rapid unexpected disassembly’ during practice. A crankshaft balance weight punched through the block, showering Clark with hot fluids and metal. From second on the grid he was running competitively when the replacement engine blew after 18 laps.

Chapman concluded that the H16 was good for no more than 300 miles between rebuilds and, accordingly, rationed mileage for the team’s final grand prix outing with the car, the 1967 season-opener in South Africa. Nevertheless Clark’s engine blew after 22 laps while new team-mate Hill crashed out.

That concluded Lotus’s relationship with an engine Stewart reckoned would have been better used as a boat anchor. While the 43 informed the design of the much more successful 49, a bald reading of the statistics – five starts, one finish – appears to confirm the 43’s undeserving reputation as a turkey.

Photo by: Motorsport Images

Clark remarkably won the only race he finished in the 43 at Watkins Glen in 1966

Still, that finish was also a win. Both 43 chassis were sold to Robs Lamplough, who converted them for use in hillclimbs (with different engines); Clark’s Watkins Glen winner went to Scottish racer Jock Russell and spent many years ‘in storage’
in a furniture truck before saloon car racer and Clark fan
Andy Middlehurst acquired and restored it with help from Team Lotus mechanic Bob Dance.

It will never race again, but this unlikely grand prix winner’s current owner remains happy to fire it up – carefully now – at selected events so fans can enjoy the singular blare of that bizarre, quixotic, ridiculous, unique engine.

Race record

Starts: 5     
Wins: 1    
Poles: 0     
Fastest laps: 0     
Podiums: 0    
Championship points: 9

Specification

Chassis: Steel monocoque   
Suspension: Rocker arms, lower wishbones, inboard coil springs/dampers (f); reversed lower wishbones, twin radius arms, outboard coil springs/dampers (r) 
Engine: Naturally aspirated BRM P75 H16 
Engine capacity: 2966cc      
Power: 650bhp @ 13000 rpm     
Gearbox: Six-speed manual 
Brakes: Steel discs front and rear      
Tyres: Firestone 
Weight: 564kg     
Notable drivers: Jim Clark, Graham Hill, Peter Arundell 

Photo by: James Mann

The 43 is not remembered well by history but did at least win a grand prix