need to remove 617 crankshaft, best procedure? - PeachParts Mercedes-Benz Forum

JB3 · #1 01-31-2014, 06:37 AM

I've messed up the orientation of a biased balance flywheel, did not mark where it went, and subsequently have caused a rear crank seal leak.

Looking on here it seems the crank pretty much has to come out anyway in order to replace the rear seal, so I am intending to just pull the entire crankshaft and take it to a machine shop with the flywheel bolted on, then have them properly re-balanced.

This is on a 300k motor, so a new timing chain wouldn't hurt anyway, but looking for advice and tips from anyone who has pulled out the crankshaft.

(The motor is in a GM van, so conceivably I can actually remove the crank with the motor still installed, there is excellent room)

Stretch · #2 01-31-2014, 07:35 AM

I think it is worth mentioning to those who don't know that you've already removed the gearbox and the flywheel.

Here's a link to the thread =>

MB 616 diesel powered Astro build

I can understand that you don't really want to remove the block from the van, however, I think you might be surprised at how heavy a crank is when it is hanging above your head on a van on a lift.

But if you want to do it that way you need to remove the lower oil pan, the upper oil pan (no cross member in the way like on a W123 / W126 - easy) and then remove the chain for the oil pump.

You could remove the timing chain from the sprocket on the crank in the following way:-

1) Remove chain tensioner
2) OPTIONAL mark chain position to camshaft cog position
3) Remove camshaft cog and let it drop (!!!!)

You should have enough wiggle on the chain to slacken it off at the crank sprocket.

To get more slack

3) Remove vacuum pump
4) OPTIONAL mark chain position to timing device
5) Remove timing device

6) OPTIONAL BUT ADVISABLE remove rocker arms from head - in this way the valves stay closed and won't get hurt

7) Remove nuts on big ends

8) Record and mark orientation and position of all big end bearing caps

9) Push connecting rods away from crank - be careful if you haven't removed rocker arms not to push too hard against the valves!!!

{Make sure the bolts in the connecting rods don't score the crank journals}

10) Loosen one of the end bearing caps on the crank and figure out a way to support it - transmission jack? ACRO prop? Broom handle? Big stick?

11) Loosen the crank bearing cap at the other end of the crank and support

12) Remove the remaining bearing caps and note position of thrust bearings in centre of crank shaft

13) Hold on to the crank (for dear life) and kick away the big sticks - don't drop the crank!

In many ways I'd rather do this with the engine out and the block up side down.

Stretch · #3 01-31-2014, 07:47 AM

Forgot =>

Adapter plate might be a pain in the arse on a normal OM617 but you've got a custom one right? You might need some fiddling there...

JB3 · #4 01-31-2014, 07:56 AM

Thanks stretch, great info!

Part of me leaving this in the van is horrible timing. I'm just about to do major construction in my work space, and cannot create a non rolling chassis because I have to basically empty the building, since the subframe has to drop to get the engine out.....

I can either wait to do this until after, or try and pull the crank, put everything inside the van, and park it outside while I wait for construction to be completed, while I'm also waiting on a machine shop.

JB3 · #5 01-31-2014, 09:15 AM

Ive been reading some excellent threads on DIYs I need to do

This whole process may happen slowly and carefully since ive already made so many mistakes. I am attempting to put together a step by step process for myself below, including parts I have to purchase for reassembly, if I miss anything or if my plan sounds wrong, please let me know!

Stretch, how does one measure crank end float?

so far my initial plan of attack is along these lines-

1. (not related to mercedes) Remove adapter plate, build brace to hold engine in upright position against transmission cross member using upper block bolts. (reason for this is that with the transmission out, the engine is braced against the hatch in the van via the valve cover to keep it from damaging the motor mounts. I will have to remove both before I am done, and the engine will need more support)

2. remove pulleys and front harmonic balancer AFTER MARKING THE ORIENTATION BETWEEN CRANK AND BALANCER (

) via the well documented method described in squiggle dogs thread here-

1980 W116 300SD OM617 Front Crank Seal Replacement

Items to collect and replace for step 2-
-Front crankshaft oil seal
-front crankshaft oil seal spacer ring

3. Remove oil pump and chain tensioner, then upper oil pan (or reverse) via this threads method by soothappens, (more excellent pics)

Oil pump chain tensioner replacement 1983 300SD

Question on this one, can I remove the upper oil pan before removing the oil pump? It looks like I can, but in order to remove the upper oil pan, do I have to remove the aluminum top front seal cover to do this?

possible Items to collect and replace for step 3 (depending on condition)-

-oil pump chain
-oil pump tensioner
-check condition of tensioner pivot area and parts as needed

my plan is to go at least to full exposure of the oil pump and tensioning apparatus, and reassess from there.

JB3 · #6 01-31-2014, 09:25 AM

also, ive spoken to the machinist, and as several people have pointed out, I need to pull a piston and rod as well for the plumb weighting to get the right crank balance.

Can a piston be installed from below on a 617? is there enough room? (I would be grabbing cyl 5 probably)

My plan of attack may change if it turns out I have to pull the head as well

Dan Stokes · #7 01-31-2014, 09:39 AM

It sure didn't look like a piston can be removed from below on mine. You might want to check my build thread as I have several pics of the bottom end of the engine as I replaced the rear seal.

I know you have to fix the seal anyhow but another balancing option is to find someone in your area who does industrial balancing - big equipment and the like. They can bring in their equipment and do it in place as long as you can provide access, like with the vehicle on a hoist. This system balances the system as a system so there is no adding bobweights, etc. We often did this with dyno setups and it really works well.

Just another choice.

Dan

Stretch · #8 01-31-2014, 09:50 AM

Quote:

Originally Posted by JB3

...

Stretch, how does one measure crank end float?

...

You mount a DTI on the end of the crank and push / pull the crank axially

Chapter 03-320 has the gen

JB3 · #9 01-31-2014, 09:51 AM

Quote:

Originally Posted by Dan Stokes

It sure didn't look like a piston can be removed from below on mine. You might want to check my build thread as I have several pics of the bottom end of the engine as I replaced the rear seal.

I know you have to fix the seal anyhow but another balancing option is to find someone in your area who does industrial balancing - big equipment and the like. They can bring in their equipment and do it in place as long as you can provide access, like with the vehicle on a hoist. This system balances the system as a system so there is no adding bobweights, etc. We often did this with dyno setups and it really works well.

Just another choice.

Dan

those are some good pics! I was thinking removable once the crank is out, and oiler is out of #5, from what you could see, do you think I could pull the piston out then? and more importantly, get the tool in that area to compress the piston rings to reinstall?

JB3 · #10 01-31-2014, 09:53 AM

Quote:

Originally Posted by Stretch

You mount a DTI on the end of the crank and push / pull the crank axially

Chapter 03-320 has the gen

great, thanks! Ill look up that data

Stretch · #11 01-31-2014, 09:56 AM

Quote:

Originally Posted by JB3

...
2. remove pulleys and front harmonic balancer AFTER MARKING THE ORIENTATION BETWEEN CRANK AND BALANCER (

) via the well documented method described in squiggle dogs thread here-

1980 W116 300SD OM617 Front Crank Seal Replacement

Items to collect and replace for step 2-
-Front crankshaft oil seal
-front crankshaft oil seal spacer ring

...

I didn't make this clear before but because the upper oil pan is gone the underside of the front crankshaft seal is gone, the seal should just drop out with the crank. As you have the turbo OM617 you can also remove the little cover above too...

...I reckon you can get away without removing the pullies and all that jazz.

See chapter 18-210 for oil pump removal hints and tips

Though this is a good point perhaps you should check with the balancing guru's if you need to remove the pullies or not. I feel perhaps pulley out of balance forces should be included (if they are there)

Note also the maximum permissible out of balance force of 15 cmg in chapter 03-318

Note also (2) if you remove the crank with the balancer and pullies in place you'll have a bugger of a time removing them - in fact 'cos your flywheel is gone you're going to struggle now...

Stretch · #12 01-31-2014, 10:03 AM

Quote:

Originally Posted by JB3

...get the tool in that area to compress the piston rings to reinstall?

That's exactly my concern - just look at the underside =>

It is curved - no piston ring compressor is going to work - you will probably break piston rings trying to do it that way.

Stretch · #13 01-31-2014, 10:08 AM

I'll try and find out the maximum allowable piston weight in an OM617 for you.

Chapter 03-316 says max allowable difference within an engine is 5 grams (with a 10 gram wear limit <= don't really understand what they mean there {taking the phrase literally} - it is probably an awkward translation which means you may add in a new piston that is within 10 grams in weight of the one you remove)

I measured my non turbo OM617 pistons (of course!) but they're not the same as yours

Stretch · #14 01-31-2014, 10:28 AM

Quote:

Originally Posted by Stretch

I'll try and find out the maximum allowable piston weight in an OM617 for you.

Chapter 03-316 says max allowable difference within an engine is 5 grams (with a 10 gram wear limit <= don't really understand what they mean there {taking the phrase literally} - it is probably an awkward translation which means you may add in a new piston that is within 10 grams in weight of the one you remove)

I measured my non turbo OM617 pistons (of course!) but they're not the same as yours

Bollocks - don't you just hate it when you google what you want to know and get your own stuff chucked back in your face?

http://www.peachparts.com/shopforum/attachments/diesel-discussion/86671d1289464860-om617-connecting-rod-weight-colour-codes-om617-engine-weights.pdf

...I'll try the German FSM (as said before my measurements are non turbo)

Obamalamadingdong · #15 01-31-2014, 01:33 PM

If you're going in that deep I have a set of new crank bearings, rod bearings, and thrust bearings all Standard size that I'll be listing in the parts section. I've got a Goetze head gasket set, a lower oil pan gasket, a set of 10 Mercedes Benz connecting rod bolts, and a handfull if not a complete set of cylinder head bolts also available.

If you decide you need part or all of that I'll give you a package deal price on it, hope you get things fixed right.