BRM P75
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The BRM P75 was a 3- litre (183 cu. in.) H engine, H16 motor racing internal combustion engine, engine, developed by British Racing Motors, BRM. The engine was relatively competitive but highly unreliable, and was used in Formula One from to .


Background


Regulation changes

In 1965, the Fédération Internationale de l'Automobile, that administered Formula One racing, agreed to raise the series' maximum engine capacity from to from 1966. Up until that point, BRM was challenging at the top with Team Lotus, Lotus, Cooper Car Company, Cooper and Scuderia Ferrari, Ferrari.


Development

BRM decided to hedge their bets by developing their existing 16 valve 1.5 litre V8 into a 32 valve 3 litre H16 (effectively two flat 8s, one on top of the other and geared together) while also developing a new 48 valve 3 litre V12 in partnership with Weslake, Harry Weslake and opt for whichever turned out to be the better powerplant. After much debate, Sir Alfred Owen decided BRM would go with the H16 and Weslake bought out BRM's involvement in the V12 and produced the engine that went on to power the Eagle Mk1, Eagle T1G. The H16's development was complicated by BRM's involvement in two further V12 designs and a 4.2 litre version of the H16 for Team Lotus, Lotus to use at the 1966 Indianapolis 500.


Reliability

Various crankshaft vibration problems dogged the engine from the start, and to compound matters quick-fix balancing weights attached to the crankshafts developed the unfortunate habit of detaching themselves and flying off within the engines causing several catastrophic engine failures. Each side of the engine had to have its own water radiator, fuel metering unit, distributor and water pump, with a common oil radiator. The first sign of trouble with the H16 came when the new engine arrived at the Team Lotus factory in Hethel, Norfolk and it required four men to lift it from the BRM truck to get into the Lotus factory. The sheer complexity of the engine led to a truly terrible record of unreliability with engine, transmission and related problems caused 27 of the powerplant's 30 retirements from 40 races.Stewart, Jackie, ''Winning Is Not Enough'', Headline Publishing Group, 2007, Page 176. The initial 32 valve engine produced at 10,250 RPM, with a later 64 valve variant raising this to at 10,500 RPM. While these constituted reasonable figures compared to the Ferrari, Honda and Weslake V12s and the Cosworth V8 of 1967, the H16 had an extremely narrow power band and was by some distance the heaviest engine on the grid, starting out weighing when introduced in 1966 with the final lightweight version lowering this to .


Formula One World Championship results

(:Template:Motorsport driver results legend, key) (Races in bold indicate pole position) (Races in ''italics'' indicate fastest lap)


References

{{BRM Formula One engines