I had stuck (BOY I mean STUKKKKK!) glow plugs in a 2.5 N/A 15J, and ended up drilling and tapping the last two and made a mini slide hammer to hoick them out.
Luckily the engine was sitting on the floor at the time.
The 4th one dropped the tip of the plug inside! AAAAAAAaaarrrggghhhhhh !!!!
I had been careful for each plug to have that piston at TDC ... I was VERY grateful about that when the tip fell off.
So I very carefully took out the injector, and leaned the engine way over so the right side was almost down, and I applied the air line to the glowplug hole, and instantly the tip of the plug was blown clean out. HOORAY!!!!
Lucky me ....
New plugs and heaps of copper grease and not too tight.
CharlesY