OM 617.952 engine people I need your help - PeachParts Mercedes-Benz Forum

C.Doner · #1 04-23-2013, 08:04 PM

Ok this is the third used engine I have obtained. This one from a friend. He gave me his word on how well it ran. I trust him on that completely.
It had an oil leak from the head gasket I noticed after I got it to my shop. I took off the head and brought it in for checking at a machine shop recommended by a trusted Indy. Its cracked RRRRG.S***,F***,D***.
The cracks are around the pre-chambers on two cylinders. Maybe it was overheated I don't know. Now I'm looking over the block and I see the cylinder liner and block have a tiny gap. I cant tell if it is corrosion or what. It looks to be on a couple of cylinders.
Is this acceptable. Should I go get my money back. I have another head but it needs a valve job. I would get that done, but there is this question over the block now. I'll take more pics later. the battery ran out on the camera so only one for now.

Austin85 · #2 04-23-2013, 11:05 PM

Quote:

Originally Posted by C.Doner

Should I go get my money back.

Yes

..

C.Doner · #3 04-24-2013, 02:39 AM

It has decent cross hatches. Is it worth a deck surfacing? It probably has to be disassembled for that right?

C.Doner · #4 04-24-2013, 02:45 AM

This one is from the other side of the same cylinder.

C.Doner · #5 04-24-2013, 02:55 AM

Its a bummer since my friend was actually reluctant to sell it to me. He wanted it because it ran so well. Now I have to bring it back in pieces. Not easy but I think he should understand. Not exactly what I had in mind. Very frusterating.

Stretch · #6 04-24-2013, 02:58 AM

What's the stuff on the top of the piston crown?

Is it just muck and gunk?

As for should you get your money back; how do you think your friend will react to the evidence?

Stretch · #7 04-24-2013, 03:03 AM

I'm like 95% sure that there's no trouble with the corrosion between the liner and the block shown in this picture

It doesn't look like there's evidence of any slippage to me. If the liner had dropped then it wouldn't be ideal...

...however it could be a good idea to get a "real life" second opinion from a decent machine shop.

Stretch · #8 04-24-2013, 03:04 AM

Question =>

How are the sides of the cylinders? Can you see any evidence of uneven wear?

Do you have a bore micrometer?

C.Doner · #9 04-24-2013, 11:20 AM

I can see most of the crosshatch marks. towards the top of the cylinders it seems to be a little more worn. I do not have a bore gauge. I may get a cheap one today from Harbor-freight.
There is no way to rotate the engine with cylinder head removed, correct?

The stuff on the piston crown is like a carbon crud. Its slightly gooey and doesn't want to come off easily. I even put ATF on it for a couple of days.
Maybe I'll bring the block down to the machine shop for them to inspect.
Can it be decked while assembled. I see a possibility for that if the timing chain was to be taken out. That would be a bunch of work.

Stretch · #10 04-24-2013, 01:42 PM

Quote:

Originally Posted by C.Doner

I can see most of the crosshatch marks. towards the top of the cylinders it seems to be a little more worn. I do not have a bore gauge. I may get a cheap one today from Harbor-freight.
There is no way to rotate the engine with cylinder head removed, correct?

...

So long as you don't mind "loosing your place" turning the crank is perfectly safe - just make sure that the timing chain doesn't get tangled in the guides; if the chain kind of doubles up and jams in the guides then you could damage them.

Quote:

Originally Posted by C.Doner

...
The stuff on the piston crown is like a carbon crud. Its slightly gooey and doesn't want to come off easily. I even put ATF on it for a couple of days.
...

Strange - can you provide a zoomed in picture? Was this engine run on non diesel "products"?

Quote:

Originally Posted by C.Doner

...
Maybe I'll bring the block down to the machine shop for them to inspect.
...

I think that that is a good idea - pictures on a forum isn't the ideal way to form a diagnosis / plan

Quote:

Originally Posted by C.Doner

...
Can it be decked while assembled. I see a possibility for that if the timing chain was to be taken out. That would be a bunch of work.

I don't know for sure - I've heard of companies that do re-bores with the engine still in the vehicle (they don't tend to have the best reputation!)

C.Doner · #11 04-25-2013, 01:10 AM

some light scoring . It must be from coking. That black stuff is more like glue or something hard. It is not east to remove, especially without scratching.
Well this one looks to be not so hot of a choice after all. I'm not having luck with used engines as of late. Three engines from wrecked cars, 2 that ran decently, all of them have major issues.
Vegi oil is the suspected in contributing to the demise in two of them. I think I may be through with used engines.
Here is a photo of the scoring. You can just barely see cross hatches through the score. I ran my fingernail over it and could not feel anything. It must have coked rings or something.

Stretch · #12 04-25-2013, 07:33 AM

That doesn't look too good =>

But I think it is very difficult to judge this with photos. The sides of the cylinder walls look shadowy which "in real life" (as in if I was seeing it for real and not in a picture) would probably indicate uneven wear. When I took my block along to an engine builder he pointed out the shadows to me and said that there wasn't any point in measuring it; he could see that it was worn.

How many broken engines have you got now? Have you reached the point where you can start making a new one?

You only need five good pistons and five new liners (bored to size) a good crankshaft and a refurbished head etc etc...

C.Doner · #13 04-26-2013, 01:58 AM

Ive got three engines at this point. An 81 TD engine from a rolled car. an 83 300DT engine from a wrecked car, and this 85 300DT engine from a rear ended car
The 81 TD engine is in the car now and has a low #5 cylinder. If possible it will stay there until another is ready to replace it. It drives ok actually. Smokes a bit but starts easily as long as it is not too cold. Water injection may help this one, but I dont want to use funding for that. I may need it for other parts. but that is tempting. Compression Psi on #5 is 225
the 83 engine is already taken apart and sits in pieces a my shop. This motor must have been run out of oil or something then repaired. the crankshaft is not original. I can tell because it had mercedes written in paint on one of the journals. Only it was spelled something like "mersedez". After I saw that i gave up on trying to fix that motor. It is sort of my practice piece at this point.

Stretch · #14 04-26-2013, 07:35 AM

OK so if you include this engine you've got two - is making one from two an option you're willing to consider? This way you keep the friendship rolling along...

Simpler=Better · #15 04-26-2013, 08:30 AM

FYI-You can make up a WI system for around $150, buying new parts. If you scrounge you can do it for less. A Devil's own pump is $100 new, a big nozzle from McMaster-Carr is $15, tubing and wires you can get at your local hardware store.