Now the fun begins - replacing crank shaft on OM603 - Page 2 - PeachParts Mercedes-Benz Forum

pimpernell · #16 11-18-2017, 09:41 AM

Its your time and money, but for you to believe that with all that was going on that "the engine was fine" is wishful thinking on your part.

The engine was noisy and leaking oil from the front seal ( the broken shaft moved in and out a bit ), apart from that it drove fine.

engatwork · #17 11-18-2017, 11:49 AM

You can pull crank without pulling head. I've done it before. Put engine at TDC before you take timing chain apart. We'll be here to advise.

Now with all that said I'd go through the engine. You are going to want to find a good machine shop if you don't have access to one already.

ah-kay · #18 11-18-2017, 12:24 PM

I would change the front and rear oil seals, rod and main bearings, plastic guides etc. Otherwise all go back in. I have 4 daily drivers in good condition so this is a play project. All reasoning and advices noted.

sixto · #19 11-18-2017, 12:25 PM

I don’t get how the part of the crank that drives the chain and valve timing is separated from the rest of the cylinders and it runs fine... or at all. Maybe it’s ‘just’ the pulley snout that broke off.

I can’t imagine any rod journal damage did not affect the rings and cylinder.

It’s possible to replace the crank without removing the head. Plastigage the main and rod journals to see if any bearings need replacement. I’ve seen a couple of three 200K plus mile 603s within new limits, not just wear limits that I wouldn’t have new bearings on hand. I forget where the 603 has thrust bearings. I’d write off the engine if any main bearing is separated from the thrust bearing. Or maybe the looseness you feel is a missing thrust bearing. Don’t forget the two bolts from the front of the head into the front cover. Since time isn’t a factor, you’re saving the cost of a head gasket and possibly a stretched head bolt or two.

And the transmission input shaft and front pump seals are accessible.

Sixto
98 E320s sedan and wagon

t walgamuth · #20 11-18-2017, 12:43 PM

When a crank breaks the break can be uneven enough to sort of Key the crank together. The engine can run but obviously its not good for things.

Once the parts work themselves loose you'll lose a lot of oil pressure, hence it siezed up IIRC. So, that implies bearing damage at least and possibly bore and ring damage as well.

With all that debris circulating any part that receives oil under pressure is likely damaged as well including rocker arms and cam bearings.

But it doesn't cost much to tear it apart and assess.

ah-kay · #21 11-19-2017, 02:18 AM

Please correct this novice if I am wrong. Is it possible to remove the crank shaft by removing the following parts with engine in the car?

1) Remove transmission
2) Remove flywheel
3) Remove all parts in front of engine front plate
4) Remove front plate
5) Remove oil pan
6) Remove crankshaft

Anything else?

engatwork · #22 11-19-2017, 07:46 AM

You have to have room to get oil pan off which you can't do with engine in car.

sixto · #23 11-19-2017, 08:11 AM

What Jim said. Is the engine technically in the car if there’s a foot gap between the mount arms and frame rails? The crankshaft is a heavy piece. It’s going to be awfully difficult to lift it into place while holding all 6 connecting rods (a) in line with their crank journals and (b) so the rod half edges don’t nick the crank journals. You can slip rubber hose over the rod bolts. That’s a difficult enough job with the engine upside-down and the head on. The block has to be lifted and rigidly supported to set proper fastener torques.

Add to your list radiator, oil pump, vacuum pump, possibly water pump...

You need the special tool to hold the ring gear steady while working on the pulley flange bolt, or remove the starter for the other kind of special tool or a big screwdriver, or have the oil pan off to wedge a crank counterweight.

Check craigslist for a free inline long block and practice your plan.

Sixto
98 E320s sedan and wagon

t walgamuth · #24 11-19-2017, 08:48 AM

Quote:

Originally Posted by ah-kay

Please correct this novice if I am wrong. Is it possible to remove the crank shaft by removing the following parts with engine in the car?

1) Remove transmission
2) Remove flywheel
3) Remove all parts in front of engine front plate
4) Remove front plate
5) Remove oil pan
6) Remove crankshaft

Anything else?

I cannot imagine it would be a satisfactory solution. You still don't know why the original crank broke do you? Also there must be debris scattered everywhere in the motor. How you gonna get it clean?

Frank Reiner · #25 11-19-2017, 09:00 AM

ah-kay:

See post #2; although perhaps mistaken for sarcasm, it was sincere.

ah-kay · #26 11-19-2017, 11:38 AM

Quote:

Originally Posted by engatwork

You have to have room to get oil pan off which you can't do with engine in car.

The oil pan is off already. That is why I saw the shaft snapped. All the points taken. It may be difficult but no one said it is impossible. I will at least give it a shot. There is always plan B.

ah-kay · #27 11-19-2017, 11:40 AM

Quote:

Originally Posted by Frank Reiner

ah-kay:

See post #2; although perhaps mistaken for sarcasm, it was sincere.

As far as I am concerned, this is plan Z. Thank but no thanks.