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

mikemass1221 · #1 04-12-2016, 09:24 AM

Well thanks to all for the input. You guys that understand the anatomy of the 606 head all nailed it. It is indeed coolant I drilled into. I feel like an idiot thinking it was fuel. But I guess the odor of fuel was already so strong (I had to remove a few fuel lines to gain better access when drilling) that I just convinced myself I was looking at diesel fuel.

I still like renaissanceman's suggestion of trying to plug the hole with a set screw. I think what I will try and do is list it for sale as a part's/project car. If someone comes along that wants to attempt this I will sell it and be done with it. In the meantime while waiting for a buyer I will tinker with it when I have spare time on weekends in the coming months, trying out his suggestion.

mikemass1221 · #2 04-12-2016, 01:29 PM

Scenario #2 above may be a real possibility.

I wish someone here could produce the same type of cross sectional diagram of the 606. I am sure it is similar to above. I have searched and searched but can find one. I would like to see exactly what the anatomy is. As you all know, the GP's in the 606 are significantly longer than other engines.

Yes, wasn't thinking correctly, nor did I plan proper. I should have held drill bit next to an intact GP and taped the bit at which point to stop.

Tired and Beyond Frustrated is more like it.

ROLLGUY · #3 04-12-2016, 06:53 PM

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.

vstech · #4 04-14-2016, 07:55 AM

Quote:

Originally Posted by ROLLGUY

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.

actually, the 604, and 605 are identical to the 606... in valve and Glow plug layout... just fewer cylinders...

601to 603 use two valves per cylinder, and a short glow plug.

Maxbumpo · #5 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?

mikemass1221 · #6 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.

Maxbumpo · #7 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

mikemass1221 · #8 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.

jay_bob · #9 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 · #10 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 · #11 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 · #12 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 · #13 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...

funola · #14 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?

ah-kay · #15 04-12-2016, 03:15 PM

Quote:

Originally Posted by funola

Still feel my comment unnecessary and redundant?

Unfortunately, Yes