Pulled engine, it's stuck
 

I'm slowing progressing on this OM617 project. The engine is at a friend/mechanic's. The Torque Converter is on the engine. I dropped it off so he could let me know what all needs to be done to it.

He called today and said he couldn't turn it. Torque Converter is on the engine and he can't get it to move.

I picked the engine up from a guy in town with several around his place. I've dropped a voicemail, text, and email but it could be a day before I hear from him due to his schedule.

I'm hoping this is a simple fix as I don't want to chase down this guy for a replacement engine.

What suggestions do you have?

Is he using a socket on the front crank nut ?

X2.

You can turn the motor over from the front crank nut with the car completely assembled, you have to do it anyway to unbolt the torque converter. The torque converter alone would have zero involvement in whether or not he could turn it over.

Bizarre he would bring up the torque converter as a problem

Is he turning the Engine Clockwise as viewed from the front of the Engine?

The OM617.952 Engines have a Timing Chain Tensioner that has a ratchet that keeps the plunger and spring from easily being depressed but even then the Manual has to only turn it in the direction it normally rotates when running.

The Engines with no turbo have timing chain tensioners that if you rotate the Engine opposite to the engines normal rotation you can collapse the spring and plunger on the timing chain tensioner relieving the tension and there is a chance of the timing chain skipping over gear teeth.

Why do you think that only applies to engines with no turbo ?

And the reason the torque converter is still on the engine is because it won't turn to access the bolts.

Don't take the engine apart, take it back to the seller and show them it is stuck.

pull the glow plugs. this should prevent compression. no compression, easier turning of the crank.

If he mounted the flywheel with the wrong bolts it could be interfering. IIRC the automatic bolts are longer than the stick bolts and will bolt up but the motor will not turn over.

Is that what I said? I gave no advice not to follow the instructions in the Service Manual. I was trying to indicate that if you have a non-turbo and you rotate it backwards it is highly likely that you can skip some teeth.
This is what I said:
"The OM617.952 Engines have a Timing Chain Tensioner that has a ratchet that keeps the plunger and spring from easily being depressed but even then the Manual has to only turn it in the direction it normally rotates when running."


The ratchet device on the Plunger of the timing Chain Tensioner is supposed to prevent the Plunger from being pushed in and compressing the Spring and that is supposed to prevent the timing chain from skipping teeth.
But, as I said the Manual still tells you not be sure to rotate the Engine in the direction of normal rotation.

By specifying ' non - turbo ' in that sentence you give the impression that it is different from the ' turbo' in that regards....
No Mercedes 615, 616, 617 NA, 617 Turbo should be turned backwards... except for the tiny amount allowed in one service procedure in the FSM...

I give credit that people can read and understand.

I must confess that I have sinned and turned my 617.952 the wrong direction more the several times. Although I did not turn it more then 1/4 of a rotation in the wrong direction.

The main thing is that people seem to trust the "mechanic" that likely worked on their gassers but may not know specific issues that can get him in trouble on a Mercedes.

X2. That would make a lot of sense, no way that sucker is coming off with a stuck motor blocking the bolts

Because the torque converter is being blamed weirdly for the lockup by the mechanic, id first personally check the engine to see for myself that it is indeed locked up and not some confusion, then take it back to the seller

I think unlikely if the torue converter is actually bolted on. They would have to be able to turn the engine to install it after the flywheel, so you would catch that before getting it bolted up.

Maybe something is jammed in the inspection panel at the back of the oil pan preventing movement though since its been pulled already. Someone has already been there and who knows the quality of work

I once worked for a month on a vehicle i was doing an engine swap on and pushed and pulled the thing in and out of the bay at work about 20 times raging at the dragging brakes. At the end when i finally started looking at the brakes i found a screwdriver jammed between the caliper and rotor. All that time i was pushing it all i had to do was fish the thing out :D

Least course of pain is to go choose another engine from him if he has more to choose from. An engine on the ground if you do not know the seller and situation well.

I have a name for them. Boat anchors. Or total crap shoots. It also looks like it was stuck before even being pulled.

Something to realize on the "don't turn backwards" issue. When a piston engine is shut off, it coasts to a stop against compression of one random cylinder. It also can spring back a bit, sometimes with force. Think of the loads on the chain at this point as the slack is instantly taken up.

Have a listen to a 90's Dodge diesel shutdown. Sometimes you hear the drive belt go scritch as the motor rotates backwards a bit and belt tension is applied to the spring loaded adjuster side.

This is far worse than manually and slowly rotating an engine backwards.