I thought your set screw was placed to plug up the glow plug hole where the flare was. Didn't even consider placing it through the prechamber into the head. How long do you expect that to last? I wouldn't even consider it. Wasted effort IMO.

Sorry, didn't mean to beat him up. It was to understand why he did what he did, learn from other's mistakes.

If I were to do such a job, I'd have a good glow plug on the bench before starting so I can take measurements in order to choose the correct drills and taps.

This pic is a direct injection engine. The 606 is indirect injection with pre combustion chamber. Totally different design.

The ONLY way I'd attempt this drill job is with guides designed for this specific job. No freaking way I'd attempt it by hand!

I had the socket on there and it wouldn't budge. I sprayed PB blaster, let sit, try again, move it ever so slightly, spray more, try to go ever so slightly the other way. Rinse, wash, repeat. On one of the attempts, the nut just broke loose while threads were still in head.

thank you for that un necessary and redundant comment... since I stated in the quoted text that I could not find an image of a 606 cutaway...:rolleyes:

Man, I wish I saw this thread last week. Great write up. Knowing what I know, I bet the removal of the injectors is the biggest key in that process. Getting the PB Blaster in there from that side it the only way to loosen the carbon build up. Which is what causes these to get stuck.

Now I am really upset knowing there was another trick I overlooked.

Isn't it FACTUALLY CORRECT as per the picture that the injector is over the GP?

It took a lot of effort for the PO to drill through the pre-chamber plus the aluminum head, and a looong drill. The head is toasted. What was done was done, move on. It may be possible to remove the pre chamber and plug the hole with a set screw. But with no dis-respect to the PO, I would leave it to the professional.

Then a 617.xxx pic would have been better than pic of a direct injection engine, where if you drilled through the glow plug, it would go into the piston (if at TDC), not into the head's coolant jacket. Equally bad in destroying an engine.

Still feel my comment unnecessary and redundant?:confused:

I take no disrespect at all. I am a weekend warrior. From now on oil changes and brakes jobs is about it for me.

Yes. Lots of effort and stupidity. Once the GP broke, I should have stepped back, taken a break, done more research and re evaluate. Instead I went ultra aggressive with the drill.

Unfortunately, Yes :(

Yup... because the 602 pic shows the closest water jacket is the other side of the head from the gp... and my pic shows how close a water jacket could be to a glow plug... especially one that's close to 6" long like the 606 plug is...

The part that was factually incorrect is: "injectors always spray fuel onto the GP ( when hot ) to fire the engine."

I agree the engine is toast.

To control drill depth you can buy different size drill stops with set screws. I don't like them and prefer a stiff tube over the drill bit as a stop. Ball point pen, nylon tubing etc cut to length works much better. I would not rely on tape as a depth marker on the drill bit because when the drill punches through the hole, you can not stop it.

I had an inspiration today in the shower for an innovative GP puller for the OM606. I think I'll design it when I get a few projects off the list. I just need a car with a OM606 in it now...anyone want to give me one?

:D:D:D

It is a quiet day at work so I am posting more than I usually do. I post necessary comment and is never redundant or off topic. I am getting out of here.

Good luck.

I still would try to repair the head rather than sell the car for $500 or so.

Check this out:
http://www.peachparts.com/shopforum/diesel-discussion/305254-innovative-new-twist-om606-glowplug-removal.html

This would probably easily pull (push, really) the broken plug in your head.

But he drilled straight through the glow plug, through the other side of the pre chamber. Your pic does not even have a pre chamber.

Not necessarily. That was my first guess.

The threaded plug might work well enough. If you can get the glow plug remains extracted first. May actually not be that difficult.

Mike,

Experience is the best teacher. You've learned a very hard lesson, don't let that go to waste. Keep wrenching! I started out twisting off rusted studs on air cooled VW engines, taking apart snowmobiles, killing various poor machines along the way, but keeping more alive than I killed.

There is a huge amount of information about any work that you care to attempt on any MB diesel from the 70's through the 90's. Take advantage of that, and I'll be you could even change out the head on your car.

Redeem yourself by replacing the head. You'll have a blast.

OM606 Head Cross Section View
 

...can be found in the MB "Model Year 1995 Model 124.131 Introduction into Service". A great resource for the OM606 NA and other changes to the 124 for
1995 model year. I think I got this book from MBNA for about $20 or $30?

Unfortunately I cannot post a scan of the appropriate page now, will do when I get home.

The picture shows what appears to be a cooling passage just below the glow plug, so if Mike angled down just a little too much, that passage could be breached.

MaxBumpo. That would be great to see. Thank you. If anything I think I angled slightly "down and to the left". By the way I never mentioned.... This is the GP to the front most of the car.

We'll get this thing fixed. I say try to salvage the head and then just watch the coolant level, unless you use the car for long trips. If it's just a commuter, then no worries if you have to admit the fix didn't work and start over with the decision to sell the car or replace the head.

Nothing to lose if the head would have to be replaced anyway!

Not if the plug is still stuck in the pre-chamber. That method works if the plug doesn't break off, but you can unscrew it all the way until the threads are out, but the carbon packing around the body makes it really hard to fully extract. If the glow plug tip is still sticking into the prechamber, when you try to pull out the pre-chamber you will probably damage both the prechamber and the head, as the glow plug tip gets sheared off.

I am sure the 606 is quite different than the 601-605. The 606 being a four valve per cyl head with the injectors in the middle of the combustion chamber, everything is laid out differently. With four valves, a prechamber, and a glow plug, there is very little space in there left for a water jacket. I can see how it would be easy to drill a little sideways and drill into a coolant passage.

Can't upload the OM606 head cross section
 

I get a "file failed to upload". I've tried various file types and sizes, same error.

Ok guys. Here are some photos and depth measurements. I took some shots from different angles so certain ones appear off center, which they probably are. And yes, I know I broke the heat exchanger. That's the least of my worries right now. It's a $100 part I will deal with when and if needed.

First we have a wide shot which is somewhat straight on:

http://i194.photobucket.com/albums/z...0210E18C7F.jpg


Next is one zoomed in a bit taken slightly from the left looking right. Note in this one the "cavity/black hole" area to the right. This is not where the coolant came from. I believe this is actually where the GP should seat, because if I probe around in there with the tip of a drill bit it comes out with carbon. The coolant started spewing from the neat smaller hole made with a 13/64 drill bit to the left.

http://i194.photobucket.com/albums/z...D2E2A043BC.jpg

Next is a picture with a drill bit in place so you can see the depth. In this pic the bit is bottomed out beyond the 13/64 hole. I measured that at about 2-7/8 inches from the face of the head. Yikes!

http://i194.photobucket.com/albums/z...CED9BEE408.jpg


Next measurement I took was drill bit in place, but not going through the 13/64 hole. I rested the bit at the level above that which measured about 2" from the face of the head, So in other words, the hole in the water jacket is 7/8" deep (hope that makes sense). I don't have a pic with the bit level a little higher. But the measurement is accurate that I am giving you.

Lastly I will just throw in some more pics from different angles where the light picked it up differently:

http://i194.photobucket.com/albums/z...7BD144F301.jpg

http://i194.photobucket.com/albums/z...5B63F1F350.jpg

http://i194.photobucket.com/albums/z...A137E9B9A4.jpg

http://i194.photobucket.com/albums/z...D9269100A8.jpg

http://i194.photobucket.com/albums/z...6D33C0CBA1.jpg

And lastly and excellent cross section photo provided by Maxbumpo.

It appears the are indeed angled slightly "down". I don't know where the hell I drilled. But take a look. Tell me what you think.

http://i194.photobucket.com/albums/z...AE850.png.jpeg

Not sure where the coolant passages are in the diagram. Maybe Maxbumpo can point them out? I assume it is the 2 non shaded areas under the glow plug (all white) that are the coolant passages. The small drill bit looks not centered and on the bottom of the hole. Is that true or an optical illusion? If so and if angled downwards could have drilled into the coolant passages depending where they are.

If you have a glow plug on the bench, you should be able to roughly determine how far and where you drilled into the head.

Looks like you cut into the coolant passage below the glow plug...so at this point, if the remnants of the glow plug could be removed, then this would have to be reconstructed somehow.

1st order of business is getting the glow plug out if you want to mess with this car. Then deal with plugging it. Good news is that there (seems) to be no damage done to the prechamber/piston/etc.

If you want to keep the car, we can keep the ideas flowing.

Nope not an optical illusion. I definitely drilled low. Now that I am really inspecting these pic I am wondering. Do you thing the center of the glow plug is the circle at about 10 o'clock to the drill bit? I am thinking yes.

I could not see this with the naked eye. But with these pics nice and zoomed in, I am thinking that is the GP.

http://i194.photobucket.com/albums/z...af67f82de7.jpg

If you have a long straight rod that fit in the small hole snugly, you should be able to "sight" where the drill bit was aimed

Hell ya! Keep em coming. This may turn into a multi month project. But now I want to see where this journey can lead. The knowledge here on this forum is great. You guys are amazing.

The early bickering aside. Every post was VERY worthy. I am a very visual person and even though the two cross sections provided earlier were not of the 606, they both gave me an idea of what the innards could look like. Please don't knock one another. I am the idiot here. Everyone's input is welcome as long as it is a well thought out thesis.

No one is going to agree on one method. That's okay. Remember, if everyone is thinking alike, then no one is thinking.

Start by drilling in the center of that circle and tapping the plug and removing with the threaded rod method detailed all over the interwebs.

Then we can see about cleaning it up and fixing the first inch or so that is FUBAR.

This thread is officially better than TV for sure.

Sent from my SGH-T889 using Tapatalk

From the photos it looks like there is a breach of the coolant passage to the right and also below the drilled hole. It also appears that the large hole (the first 3/4 of an inch) is much larger than the threads of a glow plug. The large hole also appears to be drilled low and to the left (already stated). I think if the hole was not drilled so big, there would not have been a problem. However, that is water (coolant in this case) under the bridge. I would agree with others that the head is not repairable, but that it may be able to be patched (plugged) so no coolant gets in the cylinder or out of the glow plug hole. Running it with 5 glow plugs is not the worst thing that can happen. I would say that if any more drilling or attempt to remove the remaining part of the glow plug will set you backwards more than plugging the hole and driving the car till all the plugs go bad so it will not start. As far as the fuel heater, I would just abandon it and bypass it for now. No sense spending the $ on a part that should not affect the engine's ability to start or run.

Seven eighth inch casting thickness is really good if I have that right.

Also not running a normal tap through totally might present a good thread interference point in the hole for a plug. . Trial and error to get it right but not hard. Others will have ideals.

Do you guys agree with me that the Glow Plug is that perfect circle above and to the left of the drill bit? (10-11 o'clock position?) If that is the case, my large entrance hole is so off center that it would not only involve tapping the center of the GP and still trying an extraction, but I would have to enlarge the opening even more. It is already 1/2" wide (much larger than a GP thread.)

I can carve out the upper left side of the hole with a carbide tip on a Dremmel to create more room to pull out the GP, but then I would be left with an oblong hole which would make it impossible to ever install a Helicoil or Time Sert.

So here's the suggestions so far:

1. (renaissanceman) - Continue to extract the GP, then worry later about a possible way to patch the coolant breech. Issue here is IF I can get the GP out and IF I can actually patch the cavity, I will be left with the issue of a FUBAR entrance hole to install a Helicoil.

2. (ROLLGUY) - Leave remainder of stuck GP in there as to continue to "plug" the prechamber. Install a Helicoil in existing opening and screw in a threaded "Plug". (maybe in the form of a 1/2" set screw). The coolant cavity I created will still be open behind the plug I install, but from the looks of things as is, coolant won't have any way of entering the prechamber. Downside - I am committed to only run on 5 GP's, but at least I MAY be able to run?

3. (mostly everyone else) Find a refurbished head and spend lots of money replacing or use the wise tutelage of this forum to get me through doing it myself.

Does this sound about right?

Yes those sound like your only choices to me. The other choice is to pull the head and weld up the cavity and machine it to factory specs. That is probably more costly than just replacing the head, so that makes it not a worthwhile option.

ROLLGUY - I can live with your idea. I guess the million dollar question(s) is(are):

Will a Helicoil and a set screw plug hold?

From my photos, can we be sure the coolant is not breaching any vital parts of the engine? Do I understand correct that as long as the Glow plug body is jammed in there, coolant cannot get into the prechamber and/or cylinder, pistons, etc?

If you need me to do another test of some sort to confirm, or more pics, lemme know.

If I was in the same situation as you, I would feel fine with plugging the hole and driving it. If the tip of the glow plug was stuck bad enough to break in the head, I doubt it will not seal out the coolant. As far as the plug, I would use a pipe plug and Teflon tape.

Maybe slather some jbweld in there first in case the coolant slowly washes out the carbon then one day *boom* catastrophic failure.

Sent from my SGH-T889 using Tapatalk

You need to ascertain where you have drilled into first. It is not possible for us to tell from looking at photos. Have you pulled the injector to see if you drilled through the glow plug and through the pre chamber? Is there coolant in the pre chamber? If you have not breached the pre chamber, that may make plugging that cylinder more feasible. It will lower the compression of that cylinder though since you will no longer have a glow plug tip extending into the pre chamber, which will lower the compression ratio thus the compression. Not sure what that will do to the engine.... more smoke, more vibration, lower mpg?

I have not pulled the injector yet. Will this just be a visual inspection? i.e looking for coolant or breakage below the injector? If the tip of the GP is still intact, will I see it? It is my understanding if I try to pull the prechamber out as well, that insures breakage of the tip. Sorry, I just don't know what I am expected to see down there.

Also, no one has commented yet on if that circle next to the drill bit IS the Glow Plug. The reason I keep harping on that is because if it is, it looks pretty intact to me.

If you look at the nice cutaway head diagram Maxbumpo posted, you can see that after pulling the injector, you should be able to see the glow plug tip as well as the ball pin. A normal pre chamber should be dry, covered in a light coating of carbon. DO NOT attempt to pull the pre chamber since the glow plug is still in there, you will cause more damage.

It is hard to tell by photos. You need to have a glow plug in your hand and probe what you have drilled to determine how far you have drilled.

I agree. I think I see an inner circle (glow element) and outer circle (body).

Idea: Remove the fuel thermostat, see what kind of access you have to the INSIDE of the cooling passage. Long shot, but maybe there will be a way to get to the backside of the hole?

The issue you'll need to solve is keeping the remains of the glow plug from moving backward into the cavity. Maybe pack with JBWeld before you put in the plug?

Thanks for sticking with me guys. Bare with me. I work an hour and a half from where I live. So I chat with you guys during the day and then look under the hood when I get home, access what we discuss, and then report back the next day. Please stay subscribed to this thread and I will update when I can.

Will try and get some more details tonight. But it's the weekends that I really have time to roll up the sleeves.

Since you've already breached a gallery, I say cap it up. this engine will start fine with 5 maybe 4 glowplugs.

You'll prob need to put resistors on the electrical lines to prevent codes and lights in the cabin.


If I was certain of where I was drilling and had a good feeling about getting directly into the tip of the Gp, then I would go for it. It will be harder to seal up thou if you do.

I am with Rollguy. tap it. and bolt it up.