[ Main ] [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ]

Before leaving the subject of combustion chamber design those of the race engines produced by Broadspeed and TWR cannot be ignored because they were different again. The Broadspeed engines of the mid 1970s had shallow chambers formed in the cylinder head to various shapes, the most effective being yet another due to Cosworth, originally used on their F3 MAE engine of the 1960s, resembling an opened out version of the classic BMC / Weslake heart shape. TWR used flat head engines with chambers formed in the piston crown from deep valve pockets merging into a central bowl almost exactly like the Cosworth SCA Formula 2 engine of a couple of decades or so earlier which had caused Keith Duckworth so much frustration. Like the SCA they were not ideal but were good enough to win races and it will be no surprise to learn that Cosworth played a significant part in their creation. TWR also built some 4 valve V12s but fuel consumption regulations put them at a disadvantage and the added weight at the top of the engine caused handling problems which negated the extra power, so they were never used in anger.