Glow plug change-out "disaster"...

[mikev]

So last month finally got to my 1986 M1009 "tan" I acquired from Illinois last year.

Bought it with the radiator stolen, all battery cables cut and stolen, batteries stolen and a few broke out windows.

Get it rewired and was hard to start, but started after years of sitting in the PO's lot.

I go to change out the glow plugs and all 8 had swollen tips (Autolite brand - AVOID...!!!).

Did not have the glow plug extractor tool and had to break off two of them on the passenger side. I've done plenty of change-outs and always got the broke off tips by bending them and pulling from the injector port with forceps. I bent #2 glow plug tip (I "thought") and went to fish it out. I could not find it. Go to #6 tip, push it into the pre-combustion chamber and extract it (thinking "maybe I don't really need to bend them to extract"...). Look under the CUCV, around it and inside #2 injector port - still can't find the tip...

I think, "naw, it didn't fall into the cylinder - or did it?" I put a ratchet on the crankshaft pulley bolt and sure enough the engine "stopped" during rotation. Damn...!!! Reverse direction a bit and try again - engine stopped at same location...

At this point and not owning a bore scope, I determined that the head had to come off...

So off with the cylinder head it goes and laying on top of the piston was the broken tip... I was p#ssed, but glad I didn't try to start it to "blow" it out the exhaust like I read on the 'net... I don't think the starter would have overcame the obstructing tip and would have either embedded itself into the piston or got lodged in a valve if it did start...

I learned some valuable lessons:

1. A glow plug tip CAN fall into the cylinder even if "swollen"... (there's actually enough opening for two tips side by side as the picture shows).

2. Before breaking off a tip, put cotton, toilet paper, paper towel, something below the glow plug tip to cover that damn
pre-combustion slot so nothing falls thru it...

3. Buy the swollen tip removal tool...

Hope this helps someone in the future...!!!

 

[87cr250r]

I'm curious what head gasket you have with the red silicone. I wasn't super excited about running stock because the fire rings trash the top deck of the block. I had to take 0.011" off the 6.5 I installed in my truck. I found some Cometic MLS gaskets with the exact thickness needed but they're probably leaking due to my poor specification of head finish (block shop had the deck almost mirror finish).

There is a user here that says the engine will digest the glow plug tip fine. My 6.2 ingested a star washer. It scored a cylinder a bit but I knew nothing about it until I had to tear down the engine for other reasons. A star washer is much harder than a glow plug tip. This user knows what he is doing. He's like getting relationship advice from your parents. You think you can do better but he's been there and knows what he's doing.

 

[mikev]

That "red" head gasket was from before I acquired the M1009.

I used a Fel-Pro head gasket 8726PT.

I read the same about an "already running" diesel "spitting out" a glow plug tip (not from here), but I was afraid of bending a rod, cracking a piston, etc if I tried to start it - so it sucked pulling a head because I was careless and didn't think a tip could slip thru that slot... now I know!!!

 

[nyoffroad]

Well it sure sucked that you had to go thru all that. I've had swollen GPs before but never broken any, after unscrewing them I spray them with penetrating oil (Castle Thrust is my fav.) and let sit while I do the others. After soaking awhile use vise-grips and pull straight out while twisting, some come out fairly easy, others not so much.
I did have a plug break while going up a steep hill towing a camper and all of a sudden it started knocking and pounding. I had nowhere to pull over so I let up on the throttle a bit and continued on, then just as suddenly as it started it quit knocking. When I got home I pulled some of the GP's and found one missing about half. Still have the engine and should pull the head and see what it did That was about 20 years ago.

 

[mikev]

You just proved that an engine can "survive" if the tip breaks off while running - my case was different with the engine "off"...

I was able to pull out the other six with lube and vice grips like you did, just those two would not come out... (even removed the firewall side battery tray to get better leverage)...

I even taped a small hose to the end of a shop vac to "suck out" the missing tip on #2 cylinder, but did not work...

Also, some suggested (on other threads) to use a magnetic pickup tool - news flash: glow plug tips are NOT magnetic (I tried that on a couple of brands - none were magnetic at the tip)...

So the "take-away" from my disaster is to stuff something over the slot below the tip before trying to remove a broke off tip...

 

[87cr250r]

If you put the cylinder at TDC the piston is almost touching the head so the glow plug can't fall in. If you remove the fuel injector you can push the broken plug into the pre-chamber and then remove the broken piece with pliers.

 

[mikev]

If you put the cylinder at TDC the piston is almost touching the head so the glow plug can't fall in. If you remove the fuel injector you can push the broken plug into the pre-chamber and then remove the broken piece with pliers.

Good point and another way to "skin the cat"...

I lieu of that, next time I'll stuff cotton balls or paper towel in the bottom of the pre-chamber and carefully extract the broken tip...

I really did not believe that tip fell in the cylinder - one in a million and I should start playing the Lotto...

 

[MarkM]

If you have not dropped the tip into the precup I put a cotton ball in the bottom of the precup via the fuel injector hole to catch the tip. With the aid of some custom modified needle nose pliers I was able to remove the tip with great effort. The hardest one I found was the drivers rear due to the lack of workable space. Use copper never seize on the threads of the new glow plugs. Always use an extractor when a plug is fighting you. Hope this helps.

Mark