Those are also far, far, far lower displacement. 19,000rpm, sure, but with 250cc displacement. In 1999, Formula 1 engine displacement was mandated to 2400cc a

Those are also far, far, far lower displacement. 19,000rpm, sure, but with 250cc displacement. In 1999, Formula 1 engine displacement was mandated to 2400cc and engine speeds were limited to 18,000 rpm to help keep costs in check -- they could still maintain 19,000rpm despite an order of magnitude higher engine displacement (and the far higher forces involved). Heck, remote control car nitromethane engines have operated in the 35000rpm - 40000 rpm range decades ago. But with minuscule displacements (~3cc). If valve springs worked at those speeds and 2000+ cc displacements, trust me, Formula 1 wouldn't have abandoned them several decades ago.