They’re pretty rare these days, but clutch explosions have always been an extremely dangerous side effect of too much horsepower, too much rpm or a significant parts failure. Sometimes it isn’t the clutch that causes the problem–it can also be an issue with the flywheel or pressure plate or the bolts that attach them. Regardless of the origin of the problem, it’s catastrophic to say the least.
I’ve personally seen one clutch explosion in my life, and I’d be ok if I never saw another one. My experience involved a home-built hot rod at I-40 Dragway during a nostalgia drag event in 2010. As the car passed the 330-foot mark, I heard a series of thuds, and looked up to see the car bouncing down the track, with shrapnel sprinkling the swap meet area. As the car went out of my sightline, it veered off the track, into the grass alongside the shutdown area. The pressure plate came apart, which blew through the bell housing instantly and shattered the master cylinder, leaving the driver with no brakes. A scary moment, but he escaped without injury.
My dad has seen a few but one that sticks out is Ronnie Devault’s Henry J. He’s told me about this one numerous times, but I still enjoy hearing the story. To set this up, the car always ran a small block Chevy. He built engines for himself, and my dad tells me he twisted them to 10 grand on a regular basis. Devault raced at all the local tracks, and drove the car on the street regularly. Even drove it to Chattanooga…with 6.13 gears in the rear end. Anyway, he worked up a grudge race with Ronnie and Tommy Clayton, also based out of Dayton. This race would be held at Buffalo Valley Drag Strip, which is essentially in the middle of no where…my dad says Devault told him, “I’d blow my car up before I let the Clayton brothers win”. As it turns out, a blown engine would’ve been a minor mishap compared to what happened.
My dad’s view from the starting line didn’t provide a detailed perspective, but he says it made an awful lot of noise, and the amount of dust and smoke looked like a bomb went off. As my dad and the other on lookers ran down the track to help Devault, there were thousands of tiny parts scattered across the track, oil everywhere and still no sign that Devault was ok. When they got to the car Devault was fine, but very shaken. The flywheel had separated, zinging through the aluminum bell housing and creating all sorts of havoc. It sliced through the boxed frame rail and the driver side header and exited out of the roof. With the extreme engine setback, Devault actually sat in the original Henry J back seat, which is good because if he sat any farther forward, his legs would’ve been in serious jeopardy.
I guess the moral of this story is to always have a blow proof bell housing on any type of performance car with a manual transmission. I have one in the Corvette, and it definitely helps ease the mind, even though my car doesn’t make tons of power. Obviously clutch, pressure plate and flywheel technology has come a long way, but you never know when something could fly apart.