603 #14 head job

[h2odiesel]

Ok so I've been here before, but I'd like to share the pain with my
list brothers. If I can find my old digital camera, (wifey has nice
new one at #2 daughters competition), where would the list like me to
put a few pictures of suspected #14 crackage? I've got a yahoo picture
spot, would y'all look there or is there something better?


Bob DuPuy
Parrish, FL


PS Please excuse the grammar, I seem to slip into full redneck grease
monkey speach patterns while performing shade tree mechanics.

[h2odiesel]

I threw a few pics on Yahoo Until someone expresses another opinion. I
can clearly see one crack between an exhaut valve and a prechamber in
the corresponding cylinder you can see some water stains but no "steam
cleaning". The car suddenly exhibited high cold pressure and a
cumbustion gas check showed positive in the resivour. No sign of oil
in the coolant or visa versa. No overheat while I've owned this
engine. (It is a transplant with aroung 160,000 mi)

I've got a # 17 head from a 350SDL on the original motor but if you
look around in the yahoo album you can see it has some errosion
issues. Opinions please.


Bob DuPuy
Parrish, Fl

http://pg.photos.yahoo.com/ph/h2odiesel/my_photos

[Diesel Giant]

Just attatch them when you post. You do it below where this typing shows up.

[h2odiesel]

Here is a couple shots. I think you can still make the crack out.

[BenzDiesel]

When I first started dealing with my cracked OM603 head, I took it to a machine shop that said they could repair aluminum heads for about $300.00. The guy worked on the head and repaired the crack. I installed the head and the car ran ok for a short while, about 6,000 miles; I think. Then it began to run bad again. I tried the stop leak stuff and advise no one to ever use the stuff, unless you are just trying to make it to the house and don't care if the car blows up, as long as it will make it back to the house. Then I say use the stop leak stuff. Anyway, I later found that the valves weren't properly cut to the 45 degree angle and showed the guy, but he told me he cut all his valves like that (narrow contact point between the valve face and seat). The guy had put this "temp gadget" on the back of the head that will fall off if the engine overheats or reach a certain temp, which then voids any warranty, which became a lose, lose situation for me, since improper valve cutting on an exhaust valve, "could have caused overheating", but overheating VOIDED any warranty, thus a lose, lose for me the customer. Nevertheless, I had the guy cut the valves to the 45 degree angles, eventually, but that is all he would do and basically said it was my fault.

Anyway, I paid a guy to remove that valve seat, and after removing the prechamber; I took my drill and drilled all the way through that crack, ALL THE WAY through to the water jacket in the head (you could see the hole at the water jacket, clear as day). Every welder, except for one told me that I couldn't do that (drill the hole out and weld it back up)! Anyway, the welder oven heated the head and tig welded the crack for $25.00, starting from the water jacket and built the weld up, but he didn't have the proper tools to cut and install the valve seats. So, I then took the head to another shop and let the guy cut and install a valve seat. "THEN", upon installing the prechamber holder, I mis-treaded the prechamber holder ring SOMEHOW????, and couldn't get the ring to screw back in; it was cross threaded to a fault! This was after I had bolted the head back on the engine for a second time. To make a long story short, I never found out for certain, if the weld would hold that repaired the crack, because the prechamer holder issue became larger than the initial crack problem because I couldn't find anyone with metric taps large enough to fit the ring threads to repair the threads. And when I got through welding on the head with stick rods, I guess the rings gave way and the engine lost compression. Anyway, maybe you are willing to try drilling out all of the material all the way to the water jacket and then just weld it back up so that the prechamber will fit. In "THEORY", the head should be good as new, the way I saw it. In my case, there was "zero" head warpage, just those cracks at the prechambers. And at the time, I just assumed that Mercedes designed those heads the way they were designed, so that a simple crack could be easily repaired by clearing out the hole ALL THE WAY to the water jacket and just tig welding it back up. Anyway, I still believe that head would have worked, if that prechamber ring hadn't screwed up on me. But it was a good education though!

BenzDiesel

[h2odiesel]

I thought I remembered reading that a crack from the ex valve and the prechamber was common and not a problem, but a crack from valve to valve was bad and meant a leak. Or was it the other way around?

[BenzDiesel]

However, from what I do know, most of the cracks on the OM603 occur at the prechamber. And as I stated, I know that if you remove the material all the way to the water jacket and then seal the hole beginning at that point and without any welding porosity or unwelded area at the water jacket hole, in THEORY, the leak has to be repaired, since no water can leave the water jacket from whence the water came from in the first place, when the initial crack developed. And if a welder just try to weld along the hair line of the crack, then FAILURE is almost certain. But if the crack is repaired at the water jacket and the other material is just built back up to support the prechamber and make a fit close enough to keep the combustion gases from escaping up past the prechamber, which if the gases did escape past the gap between the prechamber and valve wall (where the crack occurred) would theoretically NOT HOLD compression, which was my problem, since I couldn't get the prechamber ring to seal tight enough, once the threads were crossed; but if not for those prechamber rings, THE HEAD SHOULD HAVE BEEN ADEQUATELY REPAIRED. I mean, I tried everything to seal up that prechamber to include cutting a piece of aluminum from the thick part of a rim and shaping it and then cutting and rethreading the hole to the size of an injector (tapping to the size of the ring was like I said, out of RANGE because nobody had a tap that size that you could buy for less than what a new head would cost) and then trying to weld the piece back into the head, but never could get the rim's aluminum to hold the INJECTOR in the head with enough torque AND LEAK PROOF WELD to keep combustion gases from escaping. Anyway, from having worked on these cars for a little while now, it seems that a SECOND WAY to fix things is BUILT INTO the design on Mercedes and can be found if you look "hard" enough and your "nerves can hold up" as you be counting how much money you have tied up and lost trying to fix this Mercedes, as if it were a Chevrolet.

BenzDiesel

[reinier]

I can confirm what BenzDiesel says:

I worked at a engine overhauling company (big one) which is specialized in ALU-welding cilinder heads.
A close friend of mine still works there. The entire day he welds alu cilinder heads, off all makes. They have custom built welding equipment (how do you say it... tuned-up? Anyway, a lot more ampere)

He has welded many, many 603 heads in the past.

Sure, sometimes there were cases of waranty (all makes), but not very much.

They do it the way BenzDiesel says:

First the look INTO the head with a kind of tube-microscope, to look for cracks.
Then the cracks are marked, and machined fully out.
Then he welds the holes, after the head is heated up in an oven.
After that a long traject of machining (me too) the welds, and when the head was done, no-one could see it was welded.

But again, this shop was specialized in alu welding cilinder heads.

So its definately possible!

[Beanybean]

Originally Posted by reinier

I can confirm what BenzDiesel says:

I worked at a engine overhauling company (big one) which is specialized in ALU-welding cilinder heads.
A close friend of mine still works there. The entire day he welds alu cilinder heads, off all makes. They have custom built welding equipment (how do you say it... tuned-up? Anyway, a lot more ampere)

He has welded many, many 603 heads in the past.

Sure, sometimes there were cases of waranty (all makes), but not very much.

They do it the way BenzDiesel says:

First the look INTO the head with a kind of tube-microscope, to look for cracks.
Then the cracks are marked, and machined fully out.
Then he welds the holes, after the head is heated up in an oven.
After that a long traject of machining (me too) the welds, and when the head was done, no-one could see it was welded.

But again, this shop was specialized in alu welding cilinder heads.

So its definately possible!

Which shop is this out of curiosity?

[tjts1]

Last active 02-04-2010

[Beanybean]

Originally Posted by tjts1

Last active 02-04-2010

Meh, worth a chance, he might still get an email.

[whunter]

to help a customer with a #14 head he just removed, inspect for cracks.


.

[JPUTT]

Here is a pic of the crack I had on my #17 head at the #5 exhaust valve. It definitely was a problem pushing coolant into the exhaust. I replaced the head with a new #22 head almost 4 years ago.

[BobK]

If ya don't mind me asking, how much did that set you back and where did you purchase it? Did you do much else to the motor while you had it apart?

[JPUTT]

MB Classic Center gave me a member discount and by the time I was done about $2500 total. I installed it myself but had a local MB Indy shop rework the valves and install the pre chambers. New #22 head, head gasket, head bolts, hydraulic valve lifters (corrected a valve tic I had). The bottom end was untouched and still uses no oil after 335,000 miles (Mobile1 5W40). It does leak a drop or two every day around the injection pump. I usually get 5,000 miles on an oil change and might add a quart between changes.

That was in 2009 so I am sure the prices are higher now. I am so glad I did this because I am not second guessing myself buying a used head.