Tales of the unexpected
There were V8s, V12s and simple four-pots on the F1 grid 50 years ago, but BRM banked on an H16…
Fifty years ago – in the early weeks of 1966 – BRM was struggling against the clock to complete its prototype 3-litre Formula 1 car for the new season. It wasn’t just a new season: 1966 would also have a new 3-litre Formula 1 – and the Bourne team’s new car was the BRM P83, with its startlingly sophisticated new coupled-crankshaft H16-cylinder engine.
BRM’s finest were then struggling with similar pressures to those presently confronting their successors. The people right now finalising 2016’s crop of Mercedes-Benz, Ferrari, Renault and Honda power units for Formula 1 will probably sympathise with the travails of their predecessors. The pressures and problems are very similar, even if the technologies (and budgets) are stratospherically different.
Back then the concept behind BRM’s programme was quite easy to understand. During the old 1½-litre Formula BRM had developed into one of the strongest teams. It had won the World Championship for Constructors in 1962, then placed second in each of the following three seasons. Like Ferrari, Porsche, Maserati, Mercedes-Benz and Vanwall beforehand, it had tackled Formula 1 as a genuine constructor – making its own chassis, engine and transmission – the whole caboodle.
In Formula 1 terms the only way it could fail to qualify as what came to be known by Mr Ferrari as a grande costruttore was because BRM didn’t produce road cars. Never mind, without the BRM-owning Owen Organisation’s components supply, the wider British motor industry would have seized up overnight. So BRM represented a most substantial player.
New 3-litre Formula 1 was being promoted into 1966 as ‘The Return of Power’. By the end of 1965, Coventry Climax’s 32-valve V8s offered 212-215bhp. BRM’s 16-valve centre-exhaust P56 V8s about 220-plus bhp and Ferrari’s 1512 flat-12 was also right up there.
BRM chief engineer Tony Rudd foresaw 500bhp as the 3-litre F1 target, while the most compact packaging could minimise mass to compensate for an inevitably higher fuel consumption and heavier fuel loads.
Of course BRM had previous form where 16-cylinder Formula 1 engines were concerned. Its original supercharged BRM V16 of 1950-55 had been pretty much an over-hyped, under-developed, contentious, costly and sobering failure. But now Tony could visualise a truly modern and compact new 16-cylinder, reflecting all the experience gained from the V8s. The many cylinders of proven proportion promised high revs and exceptionally high power. The H-layout offered the minimum cross-section and was well suited to double duty as an integral part of the chassis.
Such aero engines as the wondrous wartime Napier Sabre had been similarly packaged H16s. Tony’s competitive juices as an engineer had been stirred by his main rival Walter Hassan at Coventry Climax building an exotic 1½-litre flat-16 for 1965. Tony judged its eight-cylinder length – as against the four-cylinder length of the V8s – too great for adequate installation, and so it proved. The H-layout solved such problems. It too would be only four cylinders long, and if Climax could confront 16-cylinder complexity, so surely could BRM?
Coupling the H-engine’s two crankshafts would pose some problems, but Tony had his own past experience of coupled cranks, from his Rolls-Royce days in the 1940s when he helped his friend Bill Harker rebuild his pre-war Harker Special. It comprised a Lombard chassis powered by a parallel-eight engine with two four-cylinder blocks mounted in a 20-degree vee upon a common crankcase housing two individual crankshafts, side-by-side and geared together. So into the winter of 1965-66, the first BRM P75 H16 engine came together at Bourne, while the car-build team completed the prototype P83 chassis to use it.
In autumn 1965, Tony wrote to his boss, Sir Alfred Owen “We have had a considerable setback on the 3-litre engine, due to the difficulties in casting the main crankcase. The net effect is to put the entire engine back five weeks, as the other castings are waiting their turn in the development department of Aeroplane & Motor” (the supplying foundry firm). Such long-lead items still dictate the pace of new F1 developments today.
Tony’s letter continued, “Since we have enquiries for 30 engines, it would be worthwhile tooling up to a greater extent than we did for the 1½-litre (V8).” Just imagine that, 30 H16s in battle…
By October 31, “Both halves of 3-litre crankcase bolted together. No problems.” By November 2 another batch of primary crankcases had been received at Bourne. On November 9 the first head was brought to Bourne and sectioned to check waterway formation. It was found to be “exceptionally good… and the patterns were cleared for production”. Heads were delivered and machining commenced in late November – but on November 30, “Information received from Aeroplane & Motor that second set of 3-litre heads have burst on casting.”
The Bourne machine shop hummed with prototype H16 manufacture through December, and on December 22 Tony noted to Owen: “Assembly of first 3-litre crankcase, complete with connecting rods and pistons, completed. First 3-litre car removed from jig for final riveting.”
Long lead times, supply problems, painstaking rig testing, gas-flowing; everything ate days. January 15: “Camshafts being fitted to 3-litre engine, which is in final stages of assembly… delays caused by rectification of water leaks, and difficulty in removing camshaft gears for timing.” On January 20 the engine was taken to BRM’s dyno test house on Folkingham aerodrome. Next day, “Test bed oil, water and electrical systems completed on 3-litre engine.”
On Sunday January 23, 1966, Tony reported: “As 25lb oil pressure is satisfactory, it was decided to start the engine and check the oil flows. The engine started at the first attempt, although it was noted that it did not fire until it was turning at more than 400rpm. After a few minutes light running, the engine was put on load at 3000rpm to commence running in. All instrument readings appeared satisfactory.
“The engine was opened up to 3500rpm for a few seconds before shutting down for lunch; and it was noted that the test bed propeller shaft steady bearing was showing signs of overheating… a series of oilways drilled, to permit positive lubrication of this bearing instead of relying on splash. Some difficulty was experienced restarting the engine, and it was necessary to crank it over at 500rpm before it fired. This resulted in the engine running away to 6000rpm before the test bed controlled it.
“The engine did not settle down very well to run at 3500rpm so it was stopped and checked; signs were found of loss of compression, so the engine was removed from the test bed and returned to Bourne and stripped – when it was found that the opening inlet valves had touched the closing exhaust valves on both upper banks…”
The engine was run again at the end of that week, when “Just before shutting down the engine was taken up to 6000rpm and a power reading taken, which was 2 per cent in excess of the design figure. Shortly after this the 9/16 bank cut out, and it was found that the 12/16 (sic) inlet camshaft had broken adjacent to the gear. The engine was removed from the test bed for investigation. All exhaust valves on both upper banks had touched pistons, indicating there is a timing lag.”
Through February the test team laboured – running the engine, having it fail, rebuilding it, scarce new parts rapidly depleting – to maintain testing pace. On February 14: “7501 bench-tested, with increased valve to piston clearance. Upper inlet camshaft failure again occurred – it was found that both upper camshafts had broken… Fortunately one camshaft came to rest in a position with all the valves closed – there was no sign of the valves having touched the piston and it is, therefore, established that the trouble is camshaft failure and was not brought about by direct timing variations…”
Tuesday March 9, Tony reported, “Engine 7501 bench-tested; tests terminated after two hours, due to distributor timing disc coming adrift, through the driveshaft breaking. This appeared to be due to the lightening hole down the centre of the shaft being too deep and eccentric. The engine was running between 6000-9000rpm at full throttle throughout this test, and was giving 205hp at 6000 and 364hp at 9000, which is slightly better than estimated.”
The engine was repaired overnight and next day: “7501 again run with replacement distributor shaft with dimensionally correct lightening hole. The shaft again failed at the same place at 8100rpm – the engine had been running for approximately 20 minutes at full throttle when the failure occurred.” Immediate vibration investigation suggested “Resonance occurs between 8000-9000 revs”, breaking the shaft. The fix was to be “a stronger distributor shaft in a different material”. The first race date was looming, May 14, in Monaco.
March 15 – the rebuilt 7501 was tested again: “Centre output gear stripped – running at full power at 10,000rpm. Fortunately the engine was not severely damaged.” That output gear proved to have been incorrectly heat-treated. Under-pressure suppliers were making mistakes. On March 19, gear and vibration specialists were called in, one declaring the output gears “not strong enough” – the other “believing there was no fundamental vibration problem”.
Into April the engine was built into the prototype chassis, car 8301, and starter motor problems intruded. On April 21 – Monaco just three weeks ahead – “Engine started by towing. Brakes extremely spongy; throttle pedal very heavy but smoother in operation. Gearchange far too springy and flexible. Car appears to have good traction, but lifts nose violently under acceleration… Engine requires cranking to 200rpm to fire – starter motor can only turn at 170rpm although it is designed by Lucas to turn at 245…”
Next day at Bourne, BRM’s best were all smiles, radiating pride as they showed us – the eager press – their jaw-dropping new baby. Would it prove successful? No – not really. Was that because of any lack of perspiration by its creators? No way! BRM’s eventual conqueror simply adopted a more sensible solution to winning races in ’66. Today, 50 years later, the objective is totally unchanged…
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