GLOW PLUGS - M1008/6.2 Detroit

[KAISERM715]

So I picked up a 1986 M1008 and figured I'd do a bit of maintenance on it before driving it too much and not knowing whats going on under the hood.

I pulled the glow plugs out last night and all looked ok with no swelling except the 3rd in on the driver side and the 3rd in on the passenger side, half the tip was missing. They did not snap off when I pulled them out as they were pretty carboned up and judging from the other 6 there was no swelling. I have heard stories about "catastrophic engine failures" due to broken tips getting caught up in the cylinder/exhaust port and fishing out parts and pieces via compressed air, magnets and pliers via the GP hole and injector port. Unfortunately I think I'm a bit late.


The people I purchased the truck off did a compression test and they were 320-340 straight across the board and they obviously re-installed these 2 GPs after the test unless this happened after they did the compression test. I have about 2 hours on the truck since I purchased it with no issues except hard starting. 2 broken plugs and 2 with no conductivity.

So .... what's going on in there and do you think I'm safe to keep on driving it without taking the head off and looking at the piston tops. With all the reading I have done, some say they will get exhausted and that this is fairly normal, and others think possible the worst could happen. If it hasn't happened yet, could particles that have been embedded in the top of the piston be released? I have also read that the composition of the steel in the glow plugs is thus that it will not effect the piston as the pistons are a harder steel/alloy and they will be spit out after chewed up through the exhaust port.

I think they were AC Delco, in which I have new Champion ones on my bench ready to go in. I know Champion does not seem to be a very popular replacement, but I have already bought them and installed 6.


I will try and upload the 3 pics I have taken.


Any help or past experience anyone has had with a similar situation would be fantastic.


Cheers!!

 

[KAISERM715]

 

[Monkeyboyarmy]

The broken part may still be in the combustion chamber and not made it into the cylinder....yet. I would pull the injector out and have a looksie.

 

[KAISERM715]

I guess best way is to cut the 2 injector hoses and re-clamp after checking assuming those are pressure fittings and will not just pull off the injector.

When you say have a look see, do you mean dredge a magnet around in there?? They are quite a ways in. Couldn't I just pick up a small magnet and see if it picks up anything through the GP port??

A bit of a guessing game I suppose.

 

[Warthog]

The glowplug opening is too small to fish anything out of. But it is worth a try.

You can remove the injector and it will give you a better view inside the pre-cup area. The glow plugs are located in this pre-cup area inside the head. The opening to the cylinder is small and it takes some work for a broken tip to find its way into the cylinder.

The inspection view cameras are getting cheaper and many people have one in their tool sets. You may be able to borrow one. I bought one at Harbor Freight for~$70. While I would not use it on a dialy basis it does come in handy for an occasional use (reason is the screen is too small and it makes it hard to see some things)

 

[KAISERM715]

I guess the main question is can the Detroit 6.2 process dirty old burnt up glow plug tips if they are years old, seen lots of use and could possibly be disintegrating to the point the engine could process them via the exhaust port. Assuming there may be injector failures in those 2 cilinders that may be part of the issue causing heat issues. Just to avoid a few hours of work I suppose and parts. Do you know if you can just replace 2 injectors or do us need to do the whole lot? My 2007 cummins they told me I should change them all (yeah no way) but I just did 1 and OAK. I would assume with the older detroits you can do them as needed if you can prove a failure.

Thanks again for any assistance

 

[cucvrus]

Past experience with broken glow plugs was. I was driving along 60-65 mph I heard a loud tapping sound from the engine. I slowed down and the tapping sound went away and never came back. I was far from home I assumed it was a dry nozzle knock I heard. I had that happen 3-4 times in 25 years of driving a CUCV. When I got home i parked it and it ran fine the whole time. Next morning I went to start it it would not start. This was summer time. So i pulled the glow plugs and one was completely gone from the threads down. I replaced all 8 with AC Delco 13 G glow plugs and have been driving it ever since. Hind sight is that loud tapping sound the day previous was the glow plug being digested and expelle by the engine. That was in 2010. I have been driving the truck ever since with out any adverse conditions related to that incident. I lso have taken them out that they are like you have them pictured and never heard a thing . I just removed them as a measure to diagnose hard starting. I think they disintegrated over a long period of time. And I also think they just eroded away over time a little here and there. You will not find anything in the ore chambers. It was in there it got beat to ash and was expelled already. I hope that helps. Don't worry if it was in there you can get it out without pulling the head/s. I would just put glow plugs in and run it. That is my opinion and my help on the matter. I hope it is helpful to someone.

 

[Warthog]

I agree with cucvrus. Install new ones and see how it runs.

Here is a glow plug issue that Stonpicker1 had back in 2010. He wasn't so lucky.

http://www.steelsoldiers.com/showthread.php?60982-New-6-5L-ate-a-glow-plug

 

[KAISERM715]

Well I hate to say it but this is the answer I was hoping to get. I honestly have read a few posts on the Internet on other various sites and from people who have exclusively worked on these vehicles for many years. One fellow said he has changed hundreds of sets of glow plugs on hundreds of these M1008s and he said every time there were GPs with tips missing for whatever reason. Almost every time! Also one would think with the design engineered for these Detroits that with commercial use there would be GP failures.

 

[Hasdrubal]

changed hundreds of sets of glow plugs on hundreds of these M1008s and he said every time there were GPs with tips missing for whatever reason. Almost every time!

Back in 2006, I switched to AC60G's. Since then I've never had a missing tip or swollen end in 100,000 miles. On my third set now.