Is Crankshaft play ok? - Page 2 - PeachParts Mercedes-Benz Forum

1960mog · #16 09-20-2011, 03:39 PM

Your crank is broken into two parts.
By your description, I would say around the second cylinder crank pin.
If you take the lower oil pan off, you may be able to see it.
You also can move the front of the crank in and out and see how much the flywheel moves.

Johnt49 · #17 09-20-2011, 03:44 PM

Quote:

Originally Posted by cousindave76

Is there a proper method of measuring it? I simply pushed the crank to the back of the engine as far as it would go, then pulled it forward toward the radiator and observed the distance. Yes, 1/8" is the amount I observed. Not cool.

Usually a dial indicator is used, but in this case a yard stick may suffice!

cousindave76 · #18 09-20-2011, 03:57 PM

Quote:

Originally Posted by Johnt49

Usually a dial indicator is used, but in this case a yard stick may suffice!

HAHA! Humor is how we make it through these problems ...or recognize/illustrate the deep S#!T we are in.

jt20 · #19 09-20-2011, 04:01 PM

1960mog, you sound like you've been through this before. Where did yours break? in what fashion? Any reasons?

cousindave76 · #20 09-20-2011, 04:06 PM

Quote:

Originally Posted by 1960mog

Your crank is broken into two parts.
By your description, I would say around the second cylinder crank pin.
If you take the lower oil pan off, you may be able to see it.
You also can move the front of the crank in and out and see how much the flywheel moves.

Removing the oil pan is simple enough. I suppose if I average your guys thoughts, I should start with that and leave the top side alone for now.
Due to some "chores"

I need to get done

I'll likely not get to dig in deep till next week

ALL IN!

cousindave76 · #21 09-20-2011, 04:26 PM

Quote:

Originally Posted by Johnt49

You might try turning the crank a couple degrees in both directions from the front & see if the torque converter moves at the same rate as the front, or there's "play" between the front & back of the crank. Don't go too far counter clockwise or you'll do more damage. I've seen cranks break, but remain "keyed" due to the jagged nature of the break. You've got way too much axial play in there for whatever reason.

Ah ok, I'm starting to get the picture. Busted but still "geared" to each other. Bummer.

1960mog · #22 09-20-2011, 04:39 PM

Quote:

Originally Posted by jt20

1960mog, you sound like you've been through this before. Where did yours break? in what fashion? Any reasons?

My own crank never broke, but I have seen my share of broken 617 cranks.
It happens when the fillet radius on the crank pins isn't ground to specs during a repair/ regrind of the crank shaft.
I can't remember that I ever have seen a broken Std crank.

Johnt49 · #23 09-20-2011, 04:57 PM

Until you know what is wrong I would not crank or start it again. If the crankshaft is broken & separates, lots of damage will be done when things get out of sync. As it is now you might be able to save it with another crank & bearings.

cousindave76 · #24 09-20-2011, 05:15 PM

Quote:

Originally Posted by Johnt49

Until you know what is wrong I would not crank or start it again. If the crankshaft is broken & separates, lots of damage will be done when things get out of sync. As it is now you might be able to save it with another crank & bearings.

Done with running it. Wont start it again. I was thinking about what it takes to replace a crank. I know the right thing to do is pull the engine and do a complete rebuild. I'm wondering if that is absolutely necessary? Is it possible to Macgyver it and replace just the crank and bearings from the bottom side leaving the pistons in place during the job?

Johnt49 · #25 09-20-2011, 05:40 PM

The engine will have to come out (you can't drop the pan in the car), but after that you can replace the crank without removing the pistons, rods, head etc.

jt20 · #26 09-20-2011, 05:47 PM

It is, indeed, possible to remove the upper pan and do the work.

But unless you have an extra set of hands to help manuever the crank in and out, I would not waste my time... much easier to pull the engine.

Also, swapping cranks is a gamble.

whunter · #27 09-20-2011, 06:45 PM

Quote:

Originally Posted by cousindave76

I have a friend who's 81'(aprox) 300cd with 141K started making loud metal clanking noises. He shut down and had a shop look at it to which they said "the crank shaft in crumbling". An odd assessment beings all they did was remove the crank pulley and balancer(didn't drop the oil pan). I've not been able to hear it run but I took a look at it and found that I could move the crank in and out(not up and down) about 1/8". The seal is not leaking a drop of oil. I've never inspected a 617 with no belts on before. Is this amount of in-out movement normal or should it be rock solid? And if this is not normal, does that mean the crank is shot, or is there a spacer or something may be replaced?

Thank you for you time!

You have e-mail.

Thrust Washer Set, (Shim) To Engine Main Bearings 2.15 mm
MB# 617 030 00 62
http://catalog.peachparts.com/item.wws?sku=W0133-1630995

.

.