Author Topic: Thrust Bearing Ate My Crank  (Read 3237 times)

NitroRustlerDriver

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Thrust Bearing Ate My Crank
« on: November 29, 2011, 02:05:53 AM »
Ugh, bad news. I went and checked play in the crank of my M42. Endplay is 0.070" and one side of the crank where the thrust bearing is is toast.



BIG gap.


This side looks great.




What are my options? Obviously I could find a used crank in good shape, but could the worn spot be welded and re-ground?
E30 and BMW stickers - Buy here!

Andrew Bird

DesktopDave

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Thrust Bearing Ate My Crank
« Reply #1 on: November 29, 2011, 07:15:28 AM »
Sorry to hear the bad news...I'm sure it could be repaired, but likely it'd be more than finding a good used one.  I've heard a lot of doomsday advice about that bearing, but this is the first time I've seen one damage a crank.  There's a thread around here somewhere...IIRC an M50's full-radius bearing shells fit right in.
'08 Karmesinrot 128i 6MT
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colin86325

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Thrust Bearing Ate My Crank
« Reply #2 on: November 29, 2011, 11:19:52 AM »
I had to look at 3 different used cranks beofre I found one with acceptable wear.  You can have it welded up, ground, and then renitrided but I am not sure what that would cost.

NitroRustlerDriver

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Thrust Bearing Ate My Crank
« Reply #3 on: November 29, 2011, 01:37:06 PM »
Quote from: DesktopDave;108439
There's a thread around here somewhere...IIRC an M50's full-radius bearing shells fit right in.

New bearing sets have been updated and come with a full 360 bearing now.
E30 and BMW stickers - Buy here!

Andrew Bird

wazzu70

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Thrust Bearing Ate My Crank
« Reply #4 on: November 29, 2011, 05:21:37 PM »
You are correct that the new bearing sets have a full thrust bearing.

Bummer about the crank! I got lucky and mine was in decent condition. Guess you have to go stroker now :)

Do you still have your MG?
-Nick
91 E30 M42 with VEMS

NitroRustlerDriver

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Thrust Bearing Ate My Crank
« Reply #5 on: December 01, 2011, 01:56:20 AM »
The MG is what the engine is going into. :D

http://www.r3vlimited.com/board/showthread.php?t=198933

And I found a used crank over on R3v. Hopefully it turns out to be good.
E30 and BMW stickers - Buy here!

Andrew Bird