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Crank Failure?

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chris96z

New Member
Joined
Aug 5, 2007
Messages
30
Could this be the cause to my Crank Failure? Anyone else seen this? 6 months ago my crank split and I am still not sure why.
 

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Was it cracked like that 6 months ago :eek: ? It could have had hairline cracks in it. This could definatly be a cause for a broken crank, as it could be flexing under load and throwing the balance off.
 
Yes. The bolt was loose.

No, the bolt was not loose. It took semi truck socket wrench and a leverage bar that was as long as the car to get it off. I'm thinking it was over torqued maybe. OH yeah and it was not me that did it.
 
No, the bolt was not loose. It took semi truck socket wrench and a leverage bar that was as long as the car to get it off. I'm thinking it was over torqued maybe. OH yeah and it was not me that did it.


Torque spec is like 220 Ft/Lbs min. so it is not too easy to over tighten that one.
 
An externally balanced rotating assembly, the crank broke and when it did it took out the balancer...


K.
 
A non-answer to your question.......!

You guys keep calling this POS a "balancer"?:confused:

It is a hub in reality, that is somewhat balanced to the rotating assembly and has no capability to dampen harmful harmonics.

Further, it is a cast piece like Buick used on the 2 barrel economy V-6's, and they just added an interuptor ring for the crank sensor. So after 20+ years of higher RPM ever expected of it, not to mention the fatigue factor of the material, why would you expect it to hold up?:confused:

Oh, I should have mentioned all the flex you get from the tired old cast crankshaft certainly adds to the carnage.

One of the reasons many 109 blocks can stay together in the 9's is an affordable forged steel crank used with a real harmonic balancer.

Just now replacing a crank and hub on a GN that has never been raced, but had its share of moments on the street, and this is not the first one.:)

As these original engines and parts age, we will see more disasters like this coming up.

Chris, this is like the chicken/egg question, which one came first? Neither one was and designed and built to do the job we ask of them.:biggrin:
 
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