I have an unpleasant example of what can happen if the injector installation is not carried out properly. The truck was brought to me.
According to the owner, the engine knocked and then stopped and could no longer be turned over with the starter motor.
As you can see in the video, the copper washers under the injectors are almost completely missing. The question I have is: where can the fragments escape to?

 

Man that is pitiful! Sure makes a person wonder what the story is for sure. The copper washers can oxidize when improperly torqued to begin with (exposure to heat and combustion gasses). I haven't ever really looked it up, but cylinder gas temps can probably get to within only a few hundred degrees from the copper melting point.

 

Diesel gas temperatures can reach about 3,000ƒ, while the surfaces are much, much lower. I think pistons are around 500ƒ. Copper is at 1984ƒ, which is easy to remember due to the book by Orwell.

 

Good memory aide there on 1984. The possibility of the combustion gas (a lot higher than Exhaust Gas Temps in the manifolds) getting that high is a real reminder of just how important proper injector hold down torque is, and also the need to clean the cup surface before injector installation!

And we know what CAN happen when a cylinder "over fuels"!