OM617 Crankshaft Swap - PeachParts Mercedes-Benz Forum

Kittenberger · #1 08-23-2019, 01:17 PM

I am currently working on a partial overhaul on my OM617 Turbo engine and I have a quick question. I pulled my crank shaft to replace the rear rope seal and noticed that a few of my connecting rod bearings have a significant amount of wear. The crankshaft itself doesn't look to bad so my initial thought was to just purchase new connecting rod bearings. The journal on the crankshaft measured 51.20mm, I believe this is the 3rd over repair stage. The problem I have run into is sourcing 3rd over connecting rod bearings, I've spent about an hour now looking online and have only found STD, 1st over, and 4th over.

I do have a 617 non turbo engine that I could potentially take the crankshaft from. I am just not sure if this crank shaft will bolt up to my OM617 turbo engine with out any issues. Does any one know if the non turbo crankshaft is the same as the turbo crankshaft on the OM617 engines?

engatwork · #2 08-23-2019, 01:56 PM

My gut feeling is that the non turbo should work but don't go on that

. Why not get crank to machine shop with the 4 over brgs and let them set it up unless you have a crank lathe.

hercules · #3 08-23-2019, 05:53 PM

turbo charged engine,Crankshaft surface is hardened,makes the crankshaft
stronger. Not done on 300d.

Kittenberger · #4 08-23-2019, 06:09 PM

Quote:

Originally Posted by hercules

turbo charged engine,Crankshaft surface is hardened,makes the crankshaft
stronger. Not done on 300d.

That makes sense, looks like I wont be pulling that crank then. Thanks for the input

Kittenberger · #5 08-23-2019, 06:11 PM

Quote:

Originally Posted by engatwork

My gut feeling is that the non turbo should work but don't go on that

. Why not get crank to machine shop with the 4 over brgs and let them set it up unless you have a crank lathe.

I would do that but I have only been able to source STD and 1st over bearing sets for both the main crank bearings and the connecting rod bearings.

There is a OM617 turbo engine in a junk yard about 10 minutes from me that they only want $150 for. Guess I'm spending my Monday at a junk yard pulling that engine out

I just hope the crank in that one is good. I would imagine it would be, the car only have 239K miles on it.

t walgamuth · #6 08-23-2019, 07:42 PM

The turbo crank has a bigger snout on the front. They do not interchange.

hercules · #7 08-23-2019, 07:56 PM

Turning the crank also removes hardened surface,possible breakage if not
re-hardened. Mercedes Benz so says.

t walgamuth · #8 08-23-2019, 11:03 PM

Often the cranks can be reused without being turned. I'd like to see where mb says they cannot be turned please.

hercules · #9 08-24-2019, 12:08 PM

Who said the crank could not be turned? Mercedes Benz has stated that
re-hardening was required.

97 SL320 · #10 08-24-2019, 01:34 PM

If the crank is actually 3rd size under, there should be marking on the back of the bearing shells.

The hardened crank is more of less for long tern wear than outright breakage so I'd be less concerned about going 4th size.

How do you intend to use this car and how many miles will the body go / do you intend to put this engine in another car at some point?

t walgamuth · #11 08-24-2019, 10:40 PM

How is a crank rehardened please? I have had a number of mbs rebuilt and never heard about re hardening anything.

Usaguy · #12 08-25-2019, 07:10 AM

quoting from the manual: Crankshaft must be nitride-hardened in a salt bath

https://www.startekinfo.com/StarTek/outside/12265/disc_2/program/Engine/617/03-318.pdf

also my first post on the forum

Kittenberger · #13 08-25-2019, 10:42 PM

Quote:

Originally Posted by 97 SL320

If the crank is actually 3rd size under, there should be marking on the back of the bearing shells.

The hardened crank is more of less for long tern wear than outright breakage so I'd be less concerned about going 4th size.

How do you intend to use this car and how many miles will the body go / do you intend to put this engine in another car at some point?

The car will be my daily driver. I have already put 90K on this engine but the body rusted out from driving in the winter. I purchased a 300d with a blown clutch from Texas (no rust). I would hope to get at least another 90K out of this engine in the new body.

as long as the engine is in good shape I would possibly put it in another body when the time comes, but I am not too concerned about that.

I wouldn't be afraid to get it turned to 4th over but I have not been able to locate 4th over bearing sets for the crank and connecting rods.

My plan as of now is to go to the junk yard tomorrow and pull the engine out of a 300SD and put the crankshaft from that engine in mine.

barry12345 · #14 08-26-2019, 12:02 PM

If donar car looks lke a 239K Original. I might do a compression test and a run test. If engine really is stlll good. Both cheaper and easier to get back on the road. Using it.

Kittenberger · #15 08-27-2019, 12:07 AM

Quote:

Originally Posted by barry12345

If donar car looks lke a 239K Original. I might do a compression test and a run test. If engine really is stlll good. Both cheaper and easier to get back on the road. Using it.

I was thinking about that. is there any way to do a compression test with the engine out of the car?

Also I did already spend over $1000 in parts for the rebuild already, guess I should of looked for a parts engine a little longer haha.