Thanks for the input guys. This is why I started with my "experimental" injectors before I mess with the ones I need to fix, now all I gotta do is figure out a good way to clean that hole without damaging it, and I'll be set for redoing the "good" ones. Got a new can of carby cleaner parts dip sitting on the shelf in the shop, might be able to make that work, dip it for an hour or so....

I noticed on D.G.'s injector repair notes it was mentioned something about heat shield/sealing washers, are those on all the 617 & 616 engines? I noticed there were none in that old 616 I pulled apart.

I am curious now too, I tried to use compressed air in the hole to "blow" the prechambers out after removing the ring nut above it (yes I removed the glow plugs first, and blocked the holes shut). Has anyone found a good way to remove them without pulling the head?

The reason I am getting into all of this is, aside from already mentioned unknown history and having sat, I am still having issues getting it to run correctly, and it varies by trip. One day was just dead on power & no smoke, the next trip it had better power but you could see nothing in the rearview it was smoking so bad, had a dead miss after warmed up. Next trip it ran like it had never run, set you back in the seat, no smoke, but had that dead miss again after heating up. It has what feels like a miss also around the 1000 rpm area whether cold or hot. Right now I am just trying to establish known engine condition and eliminate variables, I suspect a bad injector or weak cylinder due to the missing. It has all brand new filters, a new thermostat, and the tank/screen has been inspected. I plan to check compression when I get into it as well. The engine I'm trying to save is a 617, no turbo, unknown year, stabbed into an '80 240D. I will post the engine number tomorrow and hopefully someone will recognize the vintage.
-Chris