Either order works as long as crank at zero with the cam marks aligned. Bleed the system with the hand pump, time the pump and I'm thinking it's going to bring joy!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I sure hope so.
Thanks again.

I was not able to get the pump timing set correctly.

If I rotated the pump fully towards the engine (advanced). The start of injection is at somewhere around 90 BTDC. Tough to say exactly since timing marks on the damper only go to 80.

If I rotated the pump fully away from the engine (retard). The start of injection ends up at 69 BTDC.

I also noticed that 2 out 4 of the nuts/bolts that secure the pump were missing.
The nut on the lower most pump flange, and the bolt that secures it to the bracket in the rear were both missing. I replaced the bolt at the rear, but have left the nut at the lower pump flange off from now.

I tried the start the engine with the start of injection set at 69 BTDC, but it still wouldn't start which is not surprising. It did sound like it was closer to starting but would not.

How do I correct the pump timing so I can get the start of injection setting in range?
Can I set the engine at 0, remove the pump, turn the pump to the TDC setting, and re install it??

The pump must be removed and the marks on its input shaft aligned/indexed and then the pump gets reinstalled. I think (it has been decades) the pump gets indexed and installed with the engine at TDC but it might be at 26 degrees. I don't have access to manuals at the moment.

I found a Haynes manual to be quite helpful with this procedure.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I have a Mercedes Benz factory manual. It refers to the procedure you describe as "displacing" the pump.
The pump is removed. The pump is then re installed with the marks on the pump driver aligned and the engine at 24 BTDC. It says to introduce the pump so that the mount studs are in the middle of the slots in the flange.


I guess I'll have to try this and see if I can get the pump timing correctly set.


Thanks.

There is a paper gasket between the pump and the block. I would seal the block side of the gasket and leave the pump side either dry or lightly oiled to allow the pump to slide on it. Don't fully tighten the pump just snug it to the block until drip timing is complete. Take the time to precisely time the pump, it makes a difference. Set it, rotate the engine and re-check the setting.

One methodical step at a time and it will run.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I think this is pretty much over.

I "displaced" the injection pump in the way the factory manual describes, after which I was able to set the start of delivery at 24BTDC.

After doing this, engine still would not start. A couple times it coughed as though it was trying to start, but ultimately it did not.

The last thing I did was to re check compression on Cylinder#1 because I was curious if correcting the engine timing would have changed the number.
The compression on cylinder #1 was barely over 100psi.

Not sure how the engine lost 140psi of compression in the time it was at the shop I originally towed it to, but at one point they told me they had squirted oil into the cylinders and tried to start it, so my theory is that they managed to bend the connecting rods. That is the only way I can imagine the compression actually dropping by such a large amount.

At this point I think my only choice is to walk away from a now completely worthless car, or tear the engine down to see if my suspicion is correct.

If I end up doing the latter I will be sure to document it here.

Thanks again to everyone who contributed to this thread. I appreciate it.

If you decide to go farther, before tearing the engine down put compressed air into the cylinder and see where it exits (crankcase, intake or exhaust) as this may be a valve problem. I'd want to prove it to myself versus the shop findings.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

This is a good idea.
The problem I have is figuring out a source of compressed air, as there is none where the car will be.

It is sad that a perfectly good car/engine is 'ruined'. As I have mentioned at the beginning, low compression was never the problem. You barked up the wrong tree and here we are.

Good luck.

I don't know that I "barked up the wrong tree" but, I definitely went to the wrong shop.
The only reason I even half believed the low compression pitch was that I believed them when they said everything else (engine timing, pump timing) had been verified, which of course was not the case.
This is all covered in Post#10 of this thread.

Also, I think "perfectly good" is a bit generous in regard to this car, but it was certainly usable.

When valve timing and clearance are correct, very low compression is usually a valve problem, zero compression is usually a hole in a piston. I'm not saying it cannot be rings but it's not the common problem on really low compression. Same goes for extreme oil consumption as in gulping oil usually being valve related vs. rings.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Understood. The engine has always demonstrated some pretty extreme blowby characteristics.

My suspicion is that the connecting rods are bent, which is shortening the stroke and is therefore causing a low compression reading.

Not saying it's not valves, I'm just not sure what could have happened to the valves in the time it was at the shop, or while I was doing the work after it was there, and I'm aware of a scenario that could possibly result in a bent connecting rod.

I must have missed some thing!! Compression was checked, shop and self, pump timing
was checked ,engine was run. Now cam timing was off, pump timing was way off, enough
that engine could never have started and now rods are bent and low compression.
What is being not told? Bend the rods in this engine Please tell how!

-Engine ran when vehicle purchased, but would not start cold without starting fluid.


-I performed a number of maintenance items (valve adjust, glow plug R&R, fuel filters, compression test).


-I believe the timing chain jumped one tooth while I was adjusting valves.


-Engine no start after maintenance.



-Vehicle towed to shop


-Compression was checked by shop (they say). Their numbers were similar to mine.


- Shop says "compression is too low is reason for no start condition. I tell shop that compression numbers are higher than factory minimum spec. ask them to check engine, and pump timing.


-Engine timing checked by shop (they say)


-Pump timing checked by shop (they say)


-Shop says engine timing and pump timing both OK.


-Shop puts "a lot of oil into the cylinders" (their words), and claim the engine started.


-Shop says "Engine is toast. Needs overhaul".


-I take possession of vehicle.


-I remove, pop test, and rebuild injectors.


-I remove pre chambers, inspect, clean, and re install them with rebuilt injectors.


-I visually verify glow plug operation on Cyl #1 and #4. I watched them glow.


-Engine will not start.


-I verify Cyl#1 injector is firing. I watched it fire while cranking as it was connected to a fuel line, but pointing into the engine bay.


-I check engine timing. It is incorrect.


-I check pump timing. It is incorrect.


-I correct engine timing and pump timing.


-Engine will not start.


-I check compression on Cylinder #1. It is barely over 100psi (was 240 when vehicle was towed to shop).


This is all the data I have. Anything that is not being told, is not being told to me either. I do not have a problem admitting when I have done something wrong (like when I used the camshaft nut to rotate the engine during the valve adjust which i when I believe it the chain jumped a tooth). I realize that the whole story is needed in order for actually help to be provided.