BRM P75


The BRM P75 was a H16 engine developed by BRM, the engine was used in Formula One from 1966 to 1968.

Background

Rules 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 Lotus, Cooper and 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 while also developing a new 48 valve 3 litre V12 in partnership with 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 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 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.
The initial 32 valve engine produced 395hp at 10,250 RPM, with a later 64 valve variant raising this to 420hp 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 555lb when introduced in 1966 with the final lightweight version lowering this to 398lb.

Formula One World Championship results

YearEntrantChassisTyreDrivers123456789101112PointsWCC
Owen Racing OrganisationBRM P83MONBELFRAGBRNEDGERITAUSAMEX224th
Owen Racing OrganisationBRM P83Jackie StewartPOPORetRetRet224th
Owen Racing OrganisationBRM P83Graham HillPOPORetRetRet224th
Team LotusLotus 43Peter ArundellDNSRet135th
Team LotusLotus 43Jim ClarkRet1Ret135th
Owen Racing OrganisationBRM P83RSAMONNEDBELFRAGBRGERCANITAUSAMEX176th
Owen Racing OrganisationBRM P83Mike SpenceRet685RetRetRet55Ret5176th
Owen Racing OrganisationBRM P83Jackie StewartRetRet2Ret176th
Owen Racing OrganisationBRM P115Jackie StewartRetRetRetRetRet176th
Reg Parnell RacingBRM P83Chris Irwin5PO9RetRetRetRet-176th
Team LotusLotus 43Jim ClarkRet68th
Team LotusLotus 43Graham HillRet68th
1968Owen Racing OrganisationBRM P115RSAESPMONBELNEDFRAGBRGERITACANUSAMEX285th
1968Owen Racing OrganisationBRM P115Mike SpenceRet285th