I'm Confused

wdino73

wdino73

Member
Sep 25, 2009
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Versailles, Ky
OK, guys I'm so confused I broke another crankshaft, I tore the engine down today and the crank broke in the same spot as the other one. the first crank had a fluid dampner on it,this crank had a stock balancer on it, I was running electric fans when both of them broke... any thought, I took everything to a machine shop that I trust this afternoon, the tech told me that he seen no oiling issues or bearing issues, it has to be a harmonic issue, any thoughts..
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
4,651
116
63
Chesterfield, Mass.
wdino73 said:
OK, guys I'm so confused I broke another crankshaft, I tore the engine down today and the crank broke in the same spot as the other one. the first crank had a fluid dampner on it,this crank had a stock balancer on it, I was running electric fans when both of them broke... any thought, I took everything to a machine shop that I trust this afternoon, the tech told me that he seen no oiling issues or bearing issues, it has to be a harmonic issue, any thoughts..
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jesus man, you are a posterchild for dedication. same converter both times?
 
wdino73

wdino73

Member
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first one which was the original crank was 22222
the second crank I bought from GM was 22122
the one I'm going back with which is a used one that I had stress leaved and polished is a 11212
 
wdino73

wdino73

Member
Sep 25, 2009
735
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Versailles, Ky
that's the funny part I just use it as a work truck and some playing ( not much of that ) I was pulling about 12000lbs when it let go. It's broken in the exact same spot...wierd.
 
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Dan@PPE

Diesel Enthusiast
Aug 8, 2006
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So Cal.
So you broke the crank in your stock engine and now your built engine? or both after it was built. Did you rebalnce the rotating assembly when u went to either dampner?
 
wdino73

wdino73

Member
Sep 25, 2009
735
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Versailles, Ky
Dan@PPE said:
So you broke the crank in your stock engine and now your built engine? or both after it was built. Did you rebalnce the rotating assembly when u went to either dampner?
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I broke the crank after the build, i had the rotating mass balanced with the fluid dampner, so I install the new crank and stock balancer, and I put about 22000 mile on the engine before it let go. oh and with the fluid dampner I only got 2000 miles..
 
coldLBZ

coldLBZ

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Apr 22, 2007
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Alberta, Canada
Could there be an issue with the alignment of the mains? I would definately get it balanced again. Are you going to use the stock balancer and flexplate?
 
fctry286

fctry286

WhisperMax
Jul 30, 2010
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San Diego.
I understand, But still something has to be off balance. something could be causing the crank bearings to slightly fail and causing harsh vibes.
 
wdino73

wdino73

Member
Sep 25, 2009
735
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Versailles, Ky
fctry286 said:
I understand, But still something has to be off balance. something could be causing the crank bearings to slightly fail and causing harsh vibes.
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The bearing are in good shape, it broke right at the snout at the first counterweight on bought cranks, I got 20,000 more out of the stock balancer, the engine purrs like a kitten at any throttle pos. I just keep breaking the front of the crank off. LOL
 
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Dan@PPE

Diesel Enthusiast
Aug 8, 2006
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So Cal.
Sounds like the front of the crank need to be lightened up a bit. Both balancers you used are the heaviest on the market.
 
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