Automotive Engine explodes during dyno test

[ElliotSmith]

A high-performance diesel engine explodes into pieces while being run on a dyno test.

 

[Dr.D]

This is why such tests are conducted in specially designed test cells, rather than in someone's garage!

 

[Ranger Mike]

Crank case and crank remains attached to the dyno stand and the case separates. you use the connecting rods whipping around with some pistons attached. i would check out how the split engine case is bolted togeather for starters.. a very cool but expensive video

 

[jim hardy]

you get only so many horsepower-hours out of an engine. I prefer to not ask for them all at once.

 

[ElliotSmith]

Here's another crazy engine explosion.

 

[sandy stone]

Probably not a good idea to run alongside one of these tractors during a run.

I was once working at a plant where the bearings failed on a large, powerful centrifugal pump. The impeller left the case and was found a couple of hundred yards away.

 

[berkeman]

Here's another crazy engine explosion.

Wow, that guy running alongside dodged a bullet! Literally!

 

[ElliotSmith]

Probably not a good idea to run alongside one of these tractors during a run.

I was once working at a plant where the bearings failed on a large, powerful centrifugal pump. The impeller left the case and was found a couple of hundred yards away.

Literal engine explosions in tractor pulling are actually very common.

 

[Ketch22]

Literal engine explosions in tractor pulling are actually very common.

Many years ago I worked on a Blown fuel Nitro funny car pit crew. The owner also ran a speed shop where we built high performance engines. A customer came to us with a tractor pulling motor concept. I remember him telling the customer " We will build what you have drawn, but I do not want to even try to start it in my shop, you will need to take it home and do your own tuning."
That says a lot coming from a funny car driver, lol.

 

[trainman2001]

Like the human body, every mechanism if putting our more energy then it's designed for, it will break down. Life span is directly related to designed power output. Modern auto engines with their computer assembly systems, over head cams, direct fuel injection, turbo charging and computer controlled high voltage ignition, put out significantly more HP than their counterparts in the "Muscle Car" era of the 1960s. My Acura TL-s Type does 0-60 in 1 full second less with a 3.5 L V-6 than my "Hot rod" 1966 Ford Fairlane GT-A did with a 6.5L V-8. And the new engines run 100,000 miles without major maintenance. But every engine has it's breaking point when you try to derive more power out of it than it's weakest link.

Top Fuel dragsters today are pulling close to 10,000 hp out of what was basically a passenger car design. But the engine lasts about 1 minute total running time with the race lasting less than 4 seconds. In that four seconds, the spark plugs burn off with the engine running on compression ignition, and often one or more cylinders are dead at crossing the finish line. Between races the engines are completely rebuilt.

When on a plane flight many years ago I was sitting next to the GM of GE's aircraft engine maintenance and asked him why the Soviets were able to build jets with much higher thrust than our engines. His answer was "Ours are designed to run 2,000 hours between major overhauls, while their premise was to create high power without such long service intervals. We could design engines that could put out much higher thrust, but they would break down more frequently." When a Russian defected with a Foxbat Mig 25 to Japan we were able to see just how crudely designed the plane was and that the engines, while being powerful, were not sophisticated. We now have fighter engines that put out 40,000 lbs of thrust AND do it with the 2,000 overhaul life (F-35).

Diesel engines have another characteristic. They can run away with uncontrolled acceleration. Since they do not have an electrical ignition system as long as there's a source of fuel and air the engine will run. If the source of fuel is uncontrolled and can increase with RPM, the engine will get into a positive reinforcement loop and continue to accelerate until it destroys itself. The alternative source of fuel is often engine oil and this can get in from valve seals, turbochargers, etc. When this happens, the only way to shut the engine off is to interrupt its ability to get air. Most diesels have a flapper in the air intake line which can be shut for an emergency stop.

In my college training, one of my favorite professors was the retired engineering chief aboard a number of capital ships. On one, he was on deck and felt a vibration indicating that the engine was running away. Shutting of the fuel didn't stop it. Finally, he went up top and shoved a mattress into the air intake trunk shutting it off before it self-destructed. It doesn't matter how big the engine is... take it past the limits and something will break.

 

[Tom Kunich]

A high-performance diesel engine explodes into pieces while being run on a dyno test.

It would have been preferable for a slow motion of that explosion. You will note that the crank and rods remain with the lower case. This means that the combustion chambers were overpressured. This could have occurred in many ways - too much supercharging pressure? Was the timing belt rubber? This could have failed and left the chambers closed. As the piston started back up it would try to compress the expanded mixture.

That it failed at the rear of the motor would probably give you a clue if you had a drawing of the motor. Could it have been increasing friction at the interface between the motor and the dyno? That the crank continued to spin afterwards with no power output doesn't answer that question. Without the dyno absorbing power the connection isn't being distorted. The dyno can hold the motor back enough that the pistons will not move down fast enough after the detonation of the fuel/air mixture.

 

[ElliotSmith]

Here's what I think is a connecting rod violently shooting out the side of a Boss 429 during a dyno run.