Unless you’re into drag racing, road course work or very high performance engines the likely hood of you actually witnessing an engine grenade is very slim. For the guys that build these mills and then test them though, well, they’ve probably seen more of these babies go “pop” then they’d care to discuss. Keep in mind that the tight tolerances used to build today’s engines are so precise that if the specs are off by just a few millimeters bad things can happen. Take this big turbo diesel for example. Once the dyno testing ensues and some considerable boost is fed in, this thing goes BOOM in a very big way. Now just imagine yourself driving down the road and this happening, it may in fact put a serious damper on your day. Oh and for those of you DIY’er’s out there, it’s going to take more then some JB Weld and duct tape to put this sucker back together.