I haven't seen it yet in person but it looks really good in the pictures. Just been in storage seven years and won't start. I like the OM 617 in the W115 body, and it's red.
I have two questions;
First, the car doesn't look like it's got enough miles on it to need a ring job. I think the problem lies elsewhere. Maybe the fuel pump isn't holding up to the new fuel? Any ideas?
Second, assuming the worst, and it's really dead, what would I look for in a replacement engine? Bolt in compatability is nice, but I might be willing to do a little more work for a turbo or something. I guess I just want it to fit the tranny and the engine mounts and not get to radical. Anything I should specifically avoid? Would a 6 fit?

Um, just read in another post that the "California edition" turbos ave a bit different mounting position and might fit the w115 body. Anyone know more about this?

That engine depending on many things may still be good. Of course it could also be worn out. If the car looks decent and the interior is not all worn your chances improve the old engine may come back.

Makes sure it was not run on vegetable oil though.

What were the actual compression readings?

Sometimes when diesels sit up for a while(years) especially if they had been putted around town and never run out or had heat put into them, the engine will smoke like a chimney but can clear up after a few interstate runs.
Of course if the rings are worn... The compression doesn't come back

Well, that's the thing. He says that the compression "seems" low. I'm thinking that I'm just gonna get this car, and sort it out later. The price is right and I'll have money left over for an engine if it needs it.

If you acquire the car:

Adjust the valves. Remove the injectors and fill the cylinders with MMO. Let the MMO soak and top it off for 4 or 5 days. Immediately change the oil and filter. Charge the battery fully. Blow the excess MMO out of the cylinders and do a compression test. If it is high and EVEN among all cylinders, proceed to troubleshoot the fuel issue that prevents starting and smooth running.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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http://i959.photobucket.com/albums/a...0/sideview.png

Re post #2, I put an earlier engine (1982?) in my 1985 CA 300D, so seems the engine mounting points are identical since I used the brackets already on the earlier engine. The 1985 CA car does use the later .422 transmission, but the engine bolted up fine. If anything wasn't optimal, I haven't noticed in ~30K miles of driving.

I doubt the seller could "feel" low compression, but you can. If you turn it over by hand, you can probably tell. You should feel each cylinder strongly fight you - 5 in 2 crank revs (mark w/ chalk) and you should hear them slowly hiss down, >5 sec meaning "good compression" to me. Once it hisses down, you can continue turning. I turn my 1984 & 85 engines over using the bolt on the pwr steering pump pulley, since much easier than accessing the crank bolt. People say not to do that, but I don't know the concern. If the starter cranks it over fast enough, you might be able to tell excessive "blow-by" from puffing out the disconnected PCV hole. One likely possibility is that air got in the injection system, either from running out of fuel or a cracked rubber hose. That is easy to fix by cracking the nut (17 mm?) on top of each injector and cranking until you get fuel dribbling out. Tighten it as the fuel is flowing.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

After about 78 the mounting points for alternator and ac are different.

I'd not be surprised if the glow plugs are shot or if the owner does not know how to start a diesel.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I've read that the oil filter mounting location is different on the w123 bodies and that prohibits getting those engines in without some creativity.
Thanks for the good advice, folks. I'm starting to look forward to this.

The guy in this video says that it's common for the valves to get too tight on old Benzs. That'll cause a compression drop.
Now why would the valves get too tight? Other engines I've worked on got loose when things wore.

The W115 chassis oil filter is on the LEFT, in front of and lower than the engine mount bracket.

This is a HEAVY steel bolt shell, with a cartridge, strainer, spring/spacer, and other parts.



This engine is NOT made for a turbo...


.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

A cold compression test is pretty useless on these engines.

Check the engine oil and antifreeze level.

Don't trust the fuel guage!!!
Add fresh fuel, five gallons if possible.


I would adjust the valves, crank it, adjust the valves, crank it, adjust the valves, crank it.
Valve adjustment OM615, 616, 617 FYI.

Then glow it three times, before trying to start.

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Some engine get loose, some get tight. It depends.

Valves can end up tight because the parts stretch a tad and the valve seat wears. Some get loose because metal wears away. It just depends. On my Accord J30A1 the intakes get loose and the exhausts get tight.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

Great links, thanks!
But I'm still confused. Most of the engines I've dealt with (mostly air cooled VWs but several marine diesels, too) get loose valves as the lifters and cam wear out. How come the Mercedes gets tighter? I'm looking at some diagrams and it is a different looking lifter but I don't see how it gets tighter with wear.