I think in its oem un fooled around with design most diesels are safe in that regards. I have seen a youtube video where an old diesel seeked an alternative fuel source (ether and crank case oil) it ran away and spun a few bearings til someone choked it off, but as a newbie I cant post it here.
Its my understanding most engines have a sweet spot and really the lower of an rpms you can dial it in the more power and efficiency you will have. I heard back on my shop days inthe mid90s that it took 75 hp alone to spin a tradational v8 push rod lifter/cam shaft over 5000 rpms.