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  #16  
Old 05-10-2008, 12:43 PM
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Quote:
Originally Posted by Diesel Head View Post
In my modest 10 years experience with overhauling engines (both personal and professional) I have only come across 2 examples of being able to just replace a damaged bearing with no additional work and had success. In both cases they had been spun but did not damage the surface of the crankshaft. If you disassemble, check visually for scoring/grooves/discoloration from heat, then check with micrometer for out of round and or plastiguage and find no other issues then bearing can probably be replaced with no additional issues. Like I said though I have only ever seen/done this 2 times with success. Also make sure the locking tabs in the rod and cap are not damaged.
Good Luck

If this happened b/c of debris from the accident, perhaps it categorizes my situation as a possible candidate? The engine maintenance appears not to be the cause of this failure.

although oil starvation is a possibilty (the oil cooler was destroyed in the accident)

I should really tow.

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  #17  
Old 05-10-2008, 01:41 PM
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for ergency.

Can upper pan be removed or dropped enough to access the #2 piston without removing the engine

Can I just raise the engine and slide the upper pan just enough to check the rod (I believe #2)?
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  #18  
Old 05-10-2008, 03:28 PM
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Quote:
Originally Posted by jt20 View Post
I slept on it and examined the flakes some more. There are some that are not magnetic and break like melted plastic / have a white-ish color to them.

there are some metallic flakes that appear to not be magnetic.

The other thing is, this car was in an accident and the A/C compressor was hit just enough to crack the block in the front near the chain. This was minor and the shop repaired it. But coudn't metal from the block have gotten in there while the engine was running after the accident and seized a bearing .. perhaps momentarily?

The oil cooler was destroyed as well - oil starvation?

What are the chances it was a fluke and the bearing is turning correctly now?

Will a stethoscope help me determine what is going in there accurately enough?
It is hard to say without looking. A bearing shell has a steel back, a copper plated layer, and a layer of Babbitt material (tin/lead and ? alloy). The Babbitt part rides on the Crankshaft/Rod Journals and other parts. I don't know if the piston pins ride on Babbitt bearings in the Connecting Rod small end. When a bearing wears down to the steel backing (this is why I ask if the fragments were magnetic) it causes damage to part that rides on it. How much damage and were? You have to check; anything else is speculation and wishful thinking and goes back to what caused the problem to begin with.
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  #19  
Old 05-10-2008, 03:51 PM
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The cheapest way to fix this would be to run it until it dies, than roll the dice on a junk yard motor.
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  #20  
Old 05-10-2008, 07:38 PM
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I just finished the examination. .there is damage to crank surface on #2 and rod bearing. Seems very early, thinking of crank regrind.. will post pics and an appropriate thread later.

had it towed

any one want a wagon?
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  #21  
Old 05-10-2008, 10:12 PM
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don't give up... go get a used motor, or go pull a crank from a used motor... swap rod and crank and drive it.
I have soooooo many MB's and there are no less than 10 near me at the local PnP... pm me if you NEEEED a crank and rod.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
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  #22  
Old 05-10-2008, 10:34 PM
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Prelude to crank rebuild / replace

Thank you all for amazing input, this forum is priceless and I wish there was another way to support it other than buying parts all the time. heh.

I am now considering options for repairing this. Below are pictures of the (maybe one of many) affected area. By the amount of debris I found it is difficult to imagine that it all came from here. - input?

After reading posts: Regrind is a possibilty since the loss of material would be minimal.

the other option is a used crank. Considering all the metal shavings everywhere, this is prob the best option along with all new bearings and journals. --input?

Below: you are looking at the #2 rod cap through the upper pan opening to the oil pan. I did not remove anything but the lower / oil pan in order to reach this and turn the engine (clockwise, ...right?? the fsm is very cryptic about this minor detail.).
Attached Thumbnails
Prelude to crank rebuild / replace-crank-007.jpg   Prelude to crank rebuild / replace-crank-008.jpg   Prelude to crank rebuild / replace-crank-009.jpg  
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  #23  
Old 05-10-2008, 10:46 PM
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My 2 cents is that you cannot evaluate the crank until it is out of the engine and you can see all of the journals. If the crank journals are not deeply scored you can rub off the mushed metal on the journal with #600 or #500 Crokus Cloth (I am not sure of the spelling but that is what it sounds like) and evaluate the Crank form there.
If you decide to use the old block you will need to do a really excelent cleaning job on the oil galleries.
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  #24  
Old 05-10-2008, 10:50 PM
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That sums up many of my fears. I agree about the speculative conclusion from the one bearing.

Aren't there shards of metal in every lubricating galley?.. wouldn't cleaning everything mean basically an entire rebuild?

Are the IP and OP also at stake?
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  #25  
Old 05-11-2008, 01:32 AM
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..... Ip... it IS lubed by engine oil... so one would assume that it is in jepordy, but the galleries and the IP, all get oil AFTER the oil filter, so, any debris would be trapped in the filter. their is no bypass relief passage like in US vehicles, the bypass goes through a secondary filter, so any large debris would be trapped in the filter passage. I would pull the oil pump, and the filter and reverse the flow to be sure no chunks made it through the pump into that passage. now, fine particles of metal that made it through the filter would indeed be abrasive on all internal passages and components including the IP, so Be sure to circulate the motor with the injectors out and CLEAN CLEAN CLEAN oil in the system several times with filters in there to catch gunk.
on a rebuild, if you pull the block and have a shop clean out the block you will be further ahead, cause their machine cleans EVERYTHING really well.
compressed air and brake cleaner to flush the passages yourself.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #26  
Old 05-11-2008, 01:52 AM
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I was really hoping to drop the bottom, place the new crank / bearings / journals, then do several flushes.

This is sounding less realistic.
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  #27  
Old 05-11-2008, 02:28 AM
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It looks like new engine time to me.
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  #28  
Old 05-11-2008, 07:40 AM
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Quote:
Originally Posted by jt20 View Post
I was really hoping to drop the bottom, place the new crank / bearings / journals, then do several flushes.

This is sounding less realistic.
I am not preaching doom;but right now you do not know if a bearing spun and chewed up one of the main bearing journals or a connecting rod journal. As the other member said the oil filter is supposed to catch anything between the oil pump and the oil filter. But, read the lubrication system in ithe manual for youself. There is a relief valve in the filter housing that is there if the filter gets plugged up. When it opens unfiltered oil goes into the oil galleries. Also the oil that goes through the oil cooler is unfiltered oil; meaning that that should be cleaned out also.
Click on the first one at the top of the page and it will explain:
http://www.pauldrayton.com/uploadfiles/merc/Service/W123/Index/617T/18Lubrication.html
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Last edited by Diesel911; 05-11-2008 at 07:46 AM.
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  #29  
Old 05-11-2008, 04:11 PM
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Crank Identification 617.952

Looking for used / reground cranks.

What are the best ways to ID them? Numbers? where are they located? What should I look for in a used crank?
Should I bring my own vernier calipers or dial calipers for measurements?
Where can I find OEM spec oversize journals and rod bearings?

Thank you Again
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  #30  
Old 05-16-2008, 05:13 PM
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I have def come to the conclusion that after the accident the oil pressure was lost due to the broken oil cooler. After this the engine continued to run, vacuum lines nessed up, no shut off - you get it.

I still have yet to find a source for an engine.. To all those suggesting this is the best alternative, where are you finding them?? I potentially found one for 1700.00$

Found one regrind, but it was done with Imperial units. I don't think I am going to have much luck with oil pressure after installing that one.

The other option is:
http://www.mercedesengines.net/products.asp?cat=19&pg=1

They have the entire kit for ~ 800 after shipping.

I plan on compression testing the engine before I spend that money on rebuilding the bottom. Is this a fair game strategy?

While searching for parts I have been told numerous times that people have just shaved off the burrs on the journals / bearings - put them back together and the engines are still going. I even had one very experienced diesel mech tell me to change the oil and drive it until the engine makes noise? Is this for real?

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