Why are 'Top Fuel' drag racing engines so unreliable?

The engines in a top fueler are put under extreme pressures. They are burning huge amounts of nitro-methane and methanol to produce that kind of horsepower (around 6000-7000 hp). The nitro needs less oxygen to burn so they can put more into the cyl and it burns much hotter. After every race the mechanics need to tear down the motor and replace pistons and other parts. The connecting rods are good for about thirty passes on a alcohol car and about half that for a top fueler for example. One misfire and they are cleaning engine parts off the track. Its what makes that form of racing a challenge and exciting.

Well let me say this I love drag racing as well and when I found this out it was a dissapointment. My friend races you may have seen him on t.v its the wheeler machinery car, anyway those engines they build are usually only good for two or three passes down the track. But if you think about the engine when it has that much power and being pushed to its max for a 1/4 mile thats amazing it lasts that long.

It's the difference in the pressures in the combustion chamber.Top fuel is running a whole lot higher pressure,these engine are only meet to run for one day then be completely torn down and rebuilt.