Here's the skinny.

Bought a running 6.5NA to put in another truck. Pulled the motor, and while checking glow plugs, one came out with a broken off tip.
Took out the injector and couldn't see the broken off tip. Blew compressed air thru the glow plug hole and still no broken off tip. Remaining glow plug piece has significant carbon on the broken part which leads me to belive that it broke off awhile ago. Turned engine over by hand 4 revolutions and there was no contact in that cylinder which means there is no tip present....right?

The tips probably embedded in the piston if its not floating around in the combustion chamber. Pull the head on that side to check before you put the motor back into service.

If the end has carbon on it, the damage, if any was done long ago. Dont sweat it, I've seen alot of them like that(mostly on fords though), never been a problem. The problem is when there swelled on the end and you have to change them, there fun to get out sometimes(patience is your friend with these).

Good chance that tip blew out the exhaust long time ago. I wouldn't worry about it. Not a bad idea pullings the heads and checking it out while the engine is out. Good time for head gasket replacement.

could be imbedded, could have bent a valve...could be in the soot trapp....

I checked with the previous owner. He had the engine completely rebuilt about 20000kms ago. He said that he had never done anything with the glowplugs, but that it smoked on cold startup ever since it was rebuilt. I'd bet that the mechanic just stuck a broken off plug in it!

eeeee....i hate butchers....at least thats good news on the rebuild

The tips probably embedded in the piston if its not floating around in the combustion chamber. Pull the head on that side to check before you put the motor back into service.


X2--

Did you hear it run? If no abnormal noise, I see nothing to be gained by pulling the head, except for a lighter wallet. The mechanic might not have even pulled the plugs, he might have just surfaced them and stuck them back on. With only 20,000kms the head gaskets should still be fine.

I had a plug break off and embed in the top of the piston on my old truck. Made a horrible knocking noise and I was scared to drive it. Pulled the head off and dug it out and its been fine ever since.

The clearance is so small between the top of the piston and the head on these motors that I can't see any way you could have a glow plug tip fully embedded so far in the piston that it wouldn't touch the head. I think to do that you would have to bend a rod.

So I wouldn't bother pulling the head if you are confident there is no contact. My guess is when the piece broke off the previous owner got lucky and it blew out the exhaust instead of getting stuck in the piston.

Rent or borrow a " Bore Scope " pull the glow plug or injector and have a look. Fiber optic models (stand alone) are at harbor freight and were at radio shack, for $ 40.00 to 60.00. Electronic for ~$ 200 to $300 that will plug into a TV monitor or a laptop.

The engine runs like a top, so I don't see any point in pulling the head. Hopefully I won't regret it.

I was going to suggest trying to find someone with a boroscope, but tigert beat me to it. Even if it cost a few bucks, it is an easy way to check out the cylinder and piston.

and it is correctly called a boroscope....those things are awesome...i want one!!!