Cosworth’s DFV transformed Formula One, dominating the sport during the seventies and kick-starting the ‘kit car’ era. But BRM rarely took the easy way out. Keith Howard tells the story of their V12 — a story of what might have been
For once-embattled BRM, F1’s 1.5-litre era had been the occasion of long postponed fulfilment. The grand enterprise had finally come good, winning the drivers’ and constructors’ titles in 1962 and coming second in both through ’63-65. As Bourne pondered the arrival of the 3-litre formula in ’66, it’s understandable that some in the organisation were keen to build on established know-how by carrying over the cylinder dimensions of the little V8. That meant 16 cylinders — an unlucky number for BRM — but the logic seemed persuasive.
Harry Weslake, whose Rye-based engine firm was part-owned by the Owen Organisation, had different ideas. Aubrey Woods, co-designer of the 1.5-litre V8, had been seconded to Weslake with Peter Berthon to research 3-litre options, one of which was a four-valve V12. This was Weslake’s personal favourite and he did his utmost to promote it, but the 16-cylinder proposal eventually won out in the form of Tony Rudd’s infamous H16.
An Institution of Mechanical Engineers paper quoted the key statistics for the two prototype engines: the H16 was 20lb heavier at 380, but was 6in shorter than the 30in V12 and was reckoned to be 25bhp up on its rival with 500. In other words, the H16’s superior packaging and power potential won out. In the event, of course, the H16 would never deliver anything like 500bhp.
‘Serious consideration’ had also been given to a V8, according to the text, but Bourne’s engineers doubted they could reliably attain the 10,000rpm-plus that would be necessary to keep it competitive by 1970. As events were to prove, it wasn’t a notably well-informed piece of soothsaying.
The V12 had lost the battle but it would win the war. While the H16 went on to disgrace itself, reviving dark memories of previous dalliances with 16 cylinders, the V12 concept lived on. Weslake — having bought out the Owen interest in 1965 — developed the four-valve to power Dan Gurney’s Eagle, while Bourne’s chief engine designer Geoff Johnson was instructed to develop a V12 customer engine, a task he began in July 1966.
Although both power plants were classic 60-degree V12s with seven main bearings rather than five, in other respects they were quite different: Johnson’s engine (BRM Type 101) was a two-valve, had different cylinder dimensions (74.6 x 57.2mm as opposed to the Weslake’s 72.8 x 60) and used simplex chain to drive the camshafts rather than gears — a first for BRM — to help keep the cost down. The drawings were completed by early 1967 and the first prototype ran on 26 July. Johnson recalls it gave 360bhp immediately before any experimentation with ignition and valve timing.
Initially intended for sportscar racing — John Wyer had expressed interest in a Le Mans engine — the first customer V12 found its way into the back of Bruce McLaren’s M5A for the last four GPs of 1967, where it quickly caused the struggling H16 added embarrassment. On its first outing, at Mosport Park, McLaren finished seventh, two places adrift of Mike Spence’s BRM, but would have won had he not suffered a flat battery as a result of leaving off the alternator. Second time out at Monza, McLaren qualified third — only 0.8sec off Jim Clark’s pole in the Lotus 49 and four places ahead of Stewart’s BRM P115 — but retired with engine trouble.
When Sir Alfred Owen finally lost patience with the H16 — it appeared for the last time at Kyalami in the opening race of ’68 — the simplest solution was for BRM to revert to Plan B, the V12.
Keith Duckworth at Cosworth had meanwhile decided that a V8 was the way to go, and in 1967 had demonstrated the perspicacity of his decision in spectacular fashion. To be fair, Bourne wasn’t alone in thinking 12 cylinders superior. Ferrari had rekindled its old love affair with 12s, flat or vee — and others tried V12s too: Honda, Maserati, Matra.
The choice between V8 and V12 was a complex one: each had its advantages. A V8 was shorter (the DFV was just 21.6in long, albeit 26.5in wide), lighter and stiffer, the last making it better as a stressed chassis member. A V12, because of its larger piston area, promised more power, but only if it didn’t squander it in increased frictional and other losses. Extra length and weight made it potentially harder to package, and torsional stiffness was poorer.
After a modest showing in 1968— by which time the V12 was delivering a consistent 400bhp — it was decided that, to be fully competitive, the engine needed four valves per cylinder like the Cosworth. Prior to the H16 being abandoned, it had been destined to have a four-valve head — in fact the castings had been made — so that design was carried over.
Unusual features were a valve included angle of only 13 degrees — a consequence of the H16’s restricted space—and exhaust ports outletting into the vee. As before, the inlet ports were located between the cams, which gave an almost straight flow of air into the cylinder — though this and the valve angle would change more than once in subsequent variants.
When the new Type 142 posted 444bhp during its first power test on 13 February 1969, everyone was delighted. It was way more than had ever been achieved by the H16. Three days later, Rudd recalls, the V12 made 464bhp at 10,000rpm — ample power to take on the DFV, which even a year later was only rated at 430/440bhp at 10,000rpm. Downsides were a narrower, but still usable, power band and a 10kg increase, caused by the extra valves, springs, followers and cam lobes. The V12 now looked a match for the DFV and more.
Major personnel changes occurred at Bourne later that year. First Rudd, tired of the friction with John Surtees, left to join Lotus. Six months later, Johnson departed to become chief engineer of diesel and petrol engines at Austin Rover. Woods, who’d returned to Bourne when Anglo-American Racers closed its doors at the end of ’68, took over the V12, and another AAR refugee, Tony Southgate, set about designing a chassis to do it justice.
Southgate’s P153 certainly looked the business, but didn’t really deliver in 1970, despite Pedro Rodriguez winning at Spa and coming second at Watkins Glen. By common consent its successor, the P160, was a championship contender, but in the event could only secure Jo Siffert joint fourth in the drivers’ championship and BRM second in the constructors’. Despite changes to the induction and exhaust systems, the development of a short-stroke version that revved to 11,500rpm, and further changes to camshaft profiles etc, the V12’s power remained much the same.
Power wasn’t the problem, though: it was poor reliability, coupled with the V12’s appetite for fuel. Southgate recalls: “We had 12 engines and there wasn’t one that didn’t have a repaired block. A conrod would come out the side and we’d just weld the hole up. The engine was very light, very compact — a nice design — but to keep it short they’d made the crank and rod bearings too small. It needed bearings 20 per cent bigger, which would have made the engine a couple of inches longer. Plus we’d start races with at least eight gallons more fuel than a Cosworth car.”
When Woods left in 1972 to work for Matra, Peter Windsor-Smith, ex-chief designer at Coventry-Climax, took over development of the engine, with his previous employer Walter Hassan acting as a consultant at Louis Stanley’s request. The pace of change was not exactly electric. In his book Climax in Coventry, Hassan wrote: “I soon found, at BRM, that the problems of administration and getting delivery of a small quantity of special parts had become even more difficult. I am not trying to make excuses, either for myself or for BRM, when I say that changes agreed in 1972 were still not fitted to the grand prix cars at the start of the 1975 season.” With such stifling inertia, BRM fell rapidly behind.
Reliability continued to be a headache. Jean-Pierre Beltoise, who notched 20 retirements in 1972-74, is clear where the weaknesses lay: “We had a lot of mechanical problems. I was made very welcome in the BRM team but in fact, for the time, it was not a very professional team. Tony Southgate was a good engineer, it was only a question of the engine — and [Firestone] tyres too — but the main problem was the engine.”
Woods returned to Bourne in 1974 and, finding little changed in the V12’s output, set in train the modifications that would define the final BRM V12, Type 200. Echoing work he’d done on an abortive V12 for Hesketh, he designed a new crankcase with six separate compartments and external scavenge and pressure pumps to reduce the chumage and windage — power losses that Duckworth had been alert to from the outset with the DFV. By 1978, Type 200 would deliver a rousing 510bhp — 10bhp more than the DFV ever mustered. But it was too late. BRM was spent and F1’s turbo era was imminent.
It might all have been different had the H16 never happened. A 390hp 2-valve V12 would have given the 360hp Repco-Brabhams a good run in 1966. It might even have been strong enough to challenge the Cosworths of ’67 — and Graham Hill and Jackie Stewart might have stayed. An earlier-emerging V12 might have sneaked BRM another world title or two ahead of Northampton’s hegemony.