The crank measures up fine but I think it will benefit from a journal polish.

Some one said in an earlier post that they would be interested to see how the block was mounted on the stand.

Good luck with the repair. And i am sure it will be fine.

the crank looks exactly like mine after a overheat condition.

my 603 was a mb factory rebuilt, then overheated by water pump failure most likely

I replaced the engine with another mb factory rebuilt in 2009.

before sending the core back, we took the oil pan off and saw the blued area, and I asked the classic center in California, they said it s normal process, not from overheating the car.

__________________
'18 sprinter 144 standard height , dog hauler
'16 s550 6,xxx miles
'12 s350 27,xxx miles
'08 sl550 56,xxx miles
'91 350sdl 126,xxx miles, SOLD, in NY now with new owner
'91 560sel 81,xxx miles

what series head is on your engine ?

__________________
'18 sprinter 144 standard height , dog hauler
'16 s550 6,xxx miles
'12 s350 27,xxx miles
'08 sl550 56,xxx miles
'91 350sdl 126,xxx miles, SOLD, in NY now with new owner
'91 560sel 81,xxx miles

I got your message in the topic notification but didn't see it here .

Thanx for the new pictures and there you go : that one journal is marginal at best .

As mentioned, you might try polishing it with crocus cloth (!only!) but it doesn't appear to be even on my crappy old computer monitor so I'd get a micrometer and measure it very carefully before trusting it .

The other journals look O.K. as long as they're within spec.

-Nate

Wonder the cost today. To have the number one crank journal machined for an oversize rod bearing. If all the others journals check out great. It might clean up at the lowest oversize bearing shell available.


When into anything this deep I dislike leaving anything behind other than as it should be. I think that will not polish out alone. It is also possible the other five bearing shells as well as journals are still in great condition.


Mercedes does not always get everything right. Although to me the bottom ends of the 616, 617 and the 3 liter 603 are very rugged and not usually subject to much wear.


As for the rod caps being induction hardened. I have no issue with being enlightened. At the same time why are they all not at anywhere near the same degree of discoloration? If that was the case.

Perhaps a contact with the Mercedes classic center or the famous Mercedes engine rebuilder could elicit a firm answer? Also the other journals are too clean to indicate there was a lot of metal in the bearings. Leading me to suspect that the steel backing of the bearing shell got involved with that number one journal at one time.

Just food for thought and I have no personal issue with being wrong. At least up to this point you have not discovered anything that indicates the engine is not a sensible candidate to rebuild.

FWIW, that rough journal wasn't steel to cast iron, that's normal wear from dirty, low flowing oil .

Some of the other journals show similar wear albeit far less .

I read this you're thinking of re using any bearing shells ? . that's false economy .

I havn't see the jig for truing up _one_ journal at at time, in the car for 40 + years ! .

They used to also do single cylinder bore jobs, not so bad on old tech American lazy & slow engines but not good on anything imported .

I see OM603 engines being junked on a regular basis, I'm sure someone can get you a good used crankshaft, non ? .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I just had the tech I work with look at the pictures of the bottom of the engine with rod caps still installed. He said that is the way they looked from the factory. He spent 10 years as an engine tech at a local dealer during the nineties and during the time when 603 engines were bending rods on a regular basis.
I would have to agree that it does not appear to have overheated. The paint marks are still visible denoting bearing size on the main bearing caps.
I found a note in the intro manual for the 603 engine that states that the upper rod bearings are a different material than the lower half and to be certain not to mix them up during reassembly.

__________________
Mercedes Benz Master Tech - Retired

I thought the OM603 was the head cracking engine......? .

I agree that the blue looks like it belongs there, the condition of that one journal is suspect though .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

When abused, yes. Lots of us are still running the "Extreme failure head" with no issues. Could it be a problem in the future? Sure, but I'm not losing sleep over it.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

What I meant was : the 300 had the head issues and the 350 was the rod bender .

We drove my Brother's '87 OM603 from Coast to Coast in August with the original head, (#14 IIRC) , it ran hot going up hills with the AC on and used a steady flow of coolant , in Maine I was fiddling with it and discovered red RTV blocking the small radiator to surge tank hose when I replaced it because I noticed cracks in the rubber .

The car never seriously over heated, we'd just turn off the AC whenever the gauge passed 2/3 .

I have also seen quite a few that still run the original heads, some sort of casting shift or defect I imagine is the issue .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Right. 3.0L was head issues, 3.5L was rod-bending (in addition to other questionable design decisions).

The turbo 603 can run up ~100-105˚ on the temp gauge when pulling up hills with the A/C on and still be considered "normal" so long as the temp goes back down when the load reduces. Replacing the fan/clutch with the turbo 606 fan/clutch seems to be a good upgrade. Colder A/C and a cooler engine, I've yet to see mine get above 90˚, even when floored up some of the long steep hills around here.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

One of the forum members asked what series # cylinder head this motor had.
If I read it right it is a #22

I really didn't think this thread would get so much interest as it has. I think I will start a build thread in the "Restoration Projects and Long Term Builds" section of the forum rather than carry on in this section.
I'll put plenty of pics up. The build should start within the next week or so. Hopefully there won't be a problem sourcing parts.

series 22 is last and best from what I understand

contact thomas.hanson@mbusa.com at classic center in CA for any engine parts......

he s great to work with

tell him Hilmar sent ya !!

__________________
'18 sprinter 144 standard height , dog hauler
'16 s550 6,xxx miles
'12 s350 27,xxx miles
'08 sl550 56,xxx miles
'91 350sdl 126,xxx miles, SOLD, in NY now with new owner
'91 560sel 81,xxx miles