‘ At 12,000rpm, you have no option; you have to have a lightweight valve train so it’ s four per cylinder.’
‘ At 12,000rpm, you have no option; you have to have a lightweight valve train so it’ s four per cylinder.’
Soon after, Swindon announced a direct retro fit fourvalve-per-cylinder upgrade with the ability to rev up to 12,000rpm, plus extract more power from 964 and 993 air-cooled engines. Now, just two years later, it has shipped over 100 sets to builders and specialists such as Thornley Kelham, which had uses the heads on its European RS model. Revs don’ t just make power, they create drama and wonder.‘ Make a classic 911 air-cooled engine rev above 10,000rpm.’ That was the brief.‘ We went for 12,000rpm.’
‘ Why did we go for 12,000rpm? Because we didn’ t know what we were doing.’ Raphaël jokes.‘ Not quite true. We had good experience with high-revving 11,000rpm valve train systems. We had developed such a conversion for a Lancia Stratos.’
In his characteristically casual manner, with a sarcastic glint in his eye, Raphaël dismisses the difficulties of the Porsche motor,‘ To develop a powertrain that would reach that RPM in an old 911, all we had to do was to cool that with air instead of water …’ Gulp. Back to being serious.‘ That’ s been a lot of
Two cams and an input drive shaft occupy the same space as the original M64 engine’ s one cam
36 The Engine Rebuilder
Issue 04