OM 606 Drilled too deep trying to extract a stuck Glow Plug - Page 4 - PeachParts Mercedes-Benz Forum

Maxbumpo · #46 04-12-2016, 01:55 PM

The best option for repair is installing a used head, or a complete running engine.

Mike: Out of morbid curiosity, how did you get to the point that you broke the glow plug off?

Maxbumpo · #47 04-12-2016, 01:57 PM

For next time (or next person attempting OM606 glow plug R&R):

OM606 Glow Plug removal Tips and Tricks

jay_bob · #48 04-12-2016, 01:59 PM

That picture is of a OM602 or 603 single overhead cam. The 602/603 have the intake and exhaust valves on the right side and the pre chamber and glow plug on the left. The injectors are on the left so they can spray into the pre chamber. They are in different locations based on the head casting (different between a #14 and a #22). If you look at the inside of the head (top of the combustion chamber) on a 602 or 603 it will not be symmetrical. The 602/603 glow plugs are short and stubby - the total length of the element plus threads is on the order of a couple inches - since the pre chamber is pretty close to the left side of the head. This is similar to the legacy 616/617 engines btw.

On the 606 the dual overhead cams and 4 valves per cylinder make the top of the combustion chamber symmetrical. The pre chamber is dead center and the injectors point straight down with respect to the centerline of the piston. The glow plug now has to reach past the valve train on the left side to get into the pre chamber that is now dead center over the piston. This means the glow plug is now on the order of 6 inches long and the bore walls have coolant and oil passages on the other side.

This explains why the 606 GPs are prone to get stuck - you have about a 4 inch shaft past the threads in order for the GP to be long enough to extend into the centered pre chamber. Carbon builds up between the shaft and the bore walls, and it cools and hardens because of the relatively cool environment especially since there is oil and coolant on the other side.

The OM642 is worse - the GPs on that engine are nearly a foot long...same reason. No pre chamber on a CDI but it still has to get the business end where the action is.

vstech · #49 04-12-2016, 02:02 PM

best I can understand, you drilled off center, and went into an adjacent water jacket, and it's running out the hole you drilled in the glow hole...

I wish I could find an image of an actual 606 head cutaway... but I can't this claims to be, but obviously it's not.

mach4 · #50 04-12-2016, 02:14 PM

Quote:

Originally Posted by vstech

[IMG]

I wish I could find an image of an actual 606 head cutaway... but I can't this claims to be, but obviously it's not.

I spent a bunch of time yesterday looking for a cutaway....no joy. Lots of 617 images but no 606s.

If it turns out that the OPs head is trash, it would be fun to put it on a band saw and see what's actually going on. Might save someone else a problem.

funola · #51 04-12-2016, 02:16 PM

Quote:

Originally Posted by renaissanceman

Two cases I see:

1.) he drilled all the way through the GP, opposite side of the prechamber and through the AL wall of the head into the coolant jacket. A set screw would not cause hydrolock -- it would plug the hole on the opposite side of the prechamber.

2.) The drilled hole was off axis enough to start cutting into the head before reaching the tip of the GP, and cut into the water jacket. If this is the case, there should be little or no coolant in the prechamber or cylinder. This may be able to be patched up too. I'm hoping Mike will post photos from the borescope so we can see/help.

Probably that he was tired and frustrated and thought hewas doing what he should do. Don't beat him up more than he already is doing to himself.

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.

funola · #52 04-12-2016, 02:22 PM

Quote:

Originally Posted by vstech

best I can understand, you drilled off center, and went into an adjacent water jacket, and it's running out the hole you drilled in the glow hole...

I wish I could find an image of an actual 606 head cutaway... but I can't this claims to be, but obviously it's not.

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

vstech · #53 04-12-2016, 02:26 PM

Quote:

Originally Posted by funola

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 as 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.

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!

mikemass1221 · #54 04-12-2016, 02:28 PM

Quote:

Originally Posted by Maxbumpo

Mike: Out of morbid curiosity, how did you get to the point that you broke the glow plug off?

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.

vstech · #55 04-12-2016, 02:50 PM

Quote:

Originally Posted by funola

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

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...

mikemass1221 · #56 04-12-2016, 02:50 PM

Quote:

Originally Posted by Maxbumpo

For next time (or next person attempting OM606 glow plug R&R):

OM606 Glow Plug removal Tips and Tricks

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.

ah-kay · #57 04-12-2016, 03:02 PM

Quote:

Originally Posted by funola

This prechamber diagram is from a 190D and may resemble your 606 prechamber. Per Kartek, you would have had to drill through the glow plug then through the opposite side of the pre chamber into the aluminum head casting for coolant to leak into the pre chamber. In that case, the set screw is not going to help....it will hydro lock.

Can you measure how deep you actually drilled? It would be useful information for others attempting the same job in the future. You shouldn't have drilled more than 1/2" before tapping ( where most of the meat on the glow plug was). The glow plug gets smaller in diameter the further in you go. What were you thinking?

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.

funola · #58 04-12-2016, 03:06 PM

Quote:

Originally Posted by vstech

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...

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?

mikemass1221 · #59 04-12-2016, 03:07 PM

Quote:

Originally Posted by ah-kay

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.

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.

ah-kay · #60 04-12-2016, 03:15 PM

Quote:

Originally Posted by funola

Still feel my comment unnecessary and redundant?

Unfortunately, Yes