How to remove Om617 Crankshaft and remount it

[Hellcat94]

Hey guys. I've got an 82' Om617 TD engine on my stand and Ive been slowly cleaning it up for years.

The thing is, its a low mileage motor. But it doesn't have a flywheel!
So i got a flywheel for it & now ive got to balance it.


Im going to have the flywheel balanced to match the crank & all.



Ive never pulled the crank out.. And I am nervous about it.



The upper oil pan is out of the way and the crank is "exposed."


I know I can remove it, but I've been reading the FSM on mounting, and seems like there is a lot of dial work for checking various surfaces and such.. but as far as I could tell, there is no reference to any clearance setting upon mounting. several of the bolts have a torque and angle of rotation, but beyond that, my question is:


Does the crank have particular mounting clearances or special marks/ specs? If I remove it, do I just bolt it back in oily & evenly and torque it down?



What are the pitfalls of this? Any info would be absolutely cherished!
Please help me understand this! thank you!

[Frank Reiner]

Proceed just as you have done so many times in the past when you R&R'd a crankshaft without removing the pistons and rods. All the same precautions apply.

[Hellcat94]

Can you be more Pacific?

[Hellcat94]

My thoughts are that after removing the oil pump and oil squirters, i remove the 12 big bolts and the one small one on the front to remove each respective bearing trunion. The the crank amd all 5 pistons will come put as a unit, right? The main questions is that beyond torque specs and ring compression, when I reinstall the crank and pistons as is, or is there some required voodoo magic like setting play or clearance or whatever?

[ROLLGUY]

Originally Posted by Hellcat94

My thoughts are that after removing the oil pump and oil squirters, i remove the 12 big bolts and the one small one on the front to remove each respective bearing trunion. The the crank amd all 5 pistons will come put as a unit, right? The main questions is that beyond torque specs and ring compression, when I reinstall the crank and pistons as is, or is there some required voodoo magic like setting play or clearance or whatever?

The pistons only come out the top with the head removed. You must either remove the piston/rod assemblies (with head off), or leave all 5 pistons in their bores, and then remove the crank. You will need to put rubber hose on all the rod bolts so the crank journals do not get damaged.

This job was recently done (post #76):

Picked up a beautiful Euro 300d from its original owner

[Hellcat94]

Ok i suspected that would be the case with the pistons. With remounting I just put em on straight and torque them down with new nuts and angle of rotation, right? Also that red 300D in your link is jaw dropping.

[BWhitmore]

A good precaution to take while the crank is out is to check the bearing clearance on the rod journals. Easy to do - determine from the FSM what the rod clearance should be; purchase at your auto parts store or machine shop a product called Plastigage. You need to select the correct Plastigage based on the rod clearance specified in the FSM. Plastigage is packaged in a paper sleeve which has markings on it. Inside the sleeve is a green very small diameter (appears to be a small diameter piece of sewing thread). Pinch off a 1/4 inch piece of Plastigage and lay it on the cleaned (no oil) rod journal. Put the rod cap in place, torque the rod nuts to specification (do not turn the crank). Remove the rod cap; the Plastigage will be flattened. Compare the width of the flattened Plastigage to the markings on the paper sleeve. This comparison will tell you the amount of rod bearing clearance you have. If within spec, using your fingernail remove the flattened Plastigage from the crank rod journal, re-oil the journal, replace the rod cap and torque to spec. The same procedure can also be used with the crank main journals.

[Dan Stokes]

X2 on the Plastigage. It's amazingly accurate and while you can do all the fancy measuring (crank pins, bearing thickness, rod big end diameter and roundness check, etc.) any slight mis-measurement, mistake in recording your readings, etc. could end up with a mistake. Plastigage, properly used, is DAMN cheap insurance. I've used for over 50 years with great results.


Dan

[BWhitmore]

I should have mentioned that when buying Plastigage make sure that it is fresh. At times, Plastigage has been sitting on the shelf for quite a while.

[junqueyardjim]

Well you must do what you must do! You have to be happy with your decision. However, from my experience with these engines instead of doing what you purpose, would be to put it on and run it. I think your chance of success is excellent. I have mixed and matched a small number of them with 100% success and I think yours would work out that way as well. Keep in mind also that it is not a really high speed engine, usually run at less then 4000 rpm, and it was manufactured with a very good balance to be the norm. It wasn't a hit and miss plan!

[barry12345]

I would think some research is required to establish if these engines where internally balanced only. Have you checked your flywheel to see if it is balanced? Meaning neutrally balanced from the factory?


If it is balanced as a part. There is a chance balancing it as part of the overall engine balance was not involved. I do not have the factory service information. You may also have checked this out already and the flywheel is involved or altered. In the engine balancing as part of the procedure. .

[1983/300CD]

Originally Posted by Hellcat94

Can you be more Pacific?

“You must be shapeless, formless, like water. When you pour water in a cup, it becomes the cup. When you pour water in a bottle, it becomes the bottle. When you pour water in a teapot, it becomes the teapot. Water can drip and it can crash. Become like water my friend.”

― Bruce Lee