It does, I’ve never seen it on a DIESEL, like I said, and I’ve only seen it from NOS getting too hot. If the piston gets too hot and the rings have nowhere to go well it’s going to pop off a bit of the piston when it expands upwards in the least plain of resistance, at those temps it could weld its self on. I think it happened like this.
Engine got oil starved, see all that scoring, that’s oil starved.
Piston got too hot causing a lock up scenario.
Once OP shifted it stopped rotating and that piston was near or at TDC when it stopped moving.
The buildup of heat from heat soak finished it off, was shredded from ring damaged and when it rotated again it broke off.
a chip off like that was defiantly due to ring damage gap closure but I don’t think it came off when running as I see no damage to the top of the head or the piston top from impact when running.
As for the tensioner, it defiantly failed at the time of incident and possibly after it seized. There are no wear marks where it’s making contact and where the belt is. So it could not have rotated at all with this damage. This means it was forced over like that when the belt got enough tension on it from the locked up piston situation.
http://www.superchevy.com/how-to/148-0303-small-block-nitrous-blow-up/
http://garage.grumpysperformance.com/index.php?threads/detonation-damage.2883/
https://www.youtube.com/watch?v=AScojLj139A&t=996s
Jump to 15:20 for the carnage and a good explanation of why gas engines need more ring gap for high levels of NOS. The thing with a diesel is you dont need the gap for NOS it cools down the fuel burning and does not heat up the engine as much as a gas, too much NOS in a diesel will put out the flame so to say.
Now this happened in this video from too much heat from NOS but i suspect, from the scoring that this was oil starved cause.
I would say this looks the same 100% as OP's damage.
Caused by ring gap damage from too much heat. BUT WHY? thats the issue here. OP needs to take the lower half apart and inspect the oil pump and squirts, piston pins and crank. I highly suspect carnage to be evident in the oil pump and on the wrist pin