Crankshaft blueing / discolouration ? ? ? - Page 3 - PeachParts Mercedes-Benz Forum

fredm · #1 03-06-2018, 01:56 AM

fredm · #2 03-06-2018, 02:01 AM

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.

optimusprime · #3 03-06-2018, 04:36 AM

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

hapaschold · #4 03-06-2018, 06:10 AM

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.

hapaschold · #5 03-06-2018, 06:14 AM

what series head is on your engine ?

RPM55 · #6 03-07-2018, 08:44 AM

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.

vwnate1 · #7 03-07-2018, 10:23 AM

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 .

Diseasel300 · #8 03-07-2018, 10:26 AM

Quote:

Originally Posted by vwnate1

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

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.

vwnate1 · #9 03-07-2018, 10:53 AM

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 .

Diseasel300 · #10 03-07-2018, 11:50 AM

Quote:

Originally Posted by vwnate1

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 .

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.

fredm · #11 03-07-2018, 01:36 PM

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.

hapaschold · #12 03-07-2018, 02:05 PM

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 !!

fredm · #13 03-07-2018, 02:24 PM

Thanks for the heads up. Hopefully we can source parts a bit closer to home. :-)

vwnate1 · #14 03-07-2018, 08:42 PM

There are still quite a few of these fine cars left so junkyards get them from collisions and in the rust belt, failure to pass safety inspection so heads are not yet hard to find .

I'm guessing that's what you're talking about here as other parts are everywhere, the Internet is your friend .

I used original Mercedes parts mostly in my recent MOH of the '82 OM616 engine, the pi$ton$ nearly gave me a heart attack

but then, they're original Mahle forged, not random cast ones.....

zloca944 · #15 03-08-2018, 06:51 AM

Most interesting thing about "rod-bending' is that it only happens in US.No problems with that here in EU.I don't know why,but maybe it is fuel quality related.