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Crankshaft snout snapped

jhatley7

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True that! I'm waiting to see what all broke and what the final bill is. The initial estimate was about 500 more than another builder, but the other builder's setup comes with a new block and heads.

If I have to completely replace the heads, then it may make more financial sense to go with builder #2.
Or see how close MPR could get on pricing.
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DAVECS1

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So pictures of damage on the internet can be deceiving, but to me it looks as if there was a casting inclusion in the end of the crank. You can see a smooth area that did not take a beating when it all separated. my guess is because the material was missing to start with. To me it looks like the bolt held on for dear life thus causing all the impact damage to the crank and timing cover. Also the bolt has no impact damage, and looks to have a classic cold work, yielding, snap pattern.

Beefcake, I bough the OPG kit in the fall with the timing gear and APR bolt. It have not touched it as time got away from me. Was wondering if I can work something out to get the new bolt and the installation tool?
 
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isedawishy

isedawishy

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I have the broken snout separated now and was looking at it. There is a hairline crack all the way down the key, but I have no clue if the crack was there first and caused the breakage or of the breakage caused the crack.

I can snap pics of it later once home for anyone who is curious!
 

DAVECS1

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Something was wrong with that casting, it should not have that much precipitous grain structure. It probably cracked when the original HB was put. You can see there was very little work hardening of the metal. That means it instantaneously fractured, which should not be possible on a correctly forged piece of that size at power levels that engine can produce. It should look more like the ARP bolt when it snapped. The case hardening looks extremely thin also. Engine really deserves to be warrantied.
 

Roh92cp

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Man that's scary shit
 

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3beeps

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Something was wrong with that casting, it should not have that much precipitous grain structure. It probably cracked when the original HB was put. You can see there was very little work hardening of the metal. That means it instantaneously fractured, which should not be possible on a correctly forged piece of that size at power levels that engine can produce. It should look more like the ARP bolt when it snapped. The case hardening looks extremely thin also. Engine really deserves to be warrantied.
Do you think this failure would have happened if he stayed N/A?
 

DAVECS1

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My opinion is, yes I believe this would of eventually happened regardless of the forced induction. It would be interesting to sample and run some tests on the rest of the crank.
 

veeefour

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Those forged stock cranks are impossible to snap - something very wrong with that setup!
 

dubster99

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Could it have been cracked during the balancer install?
 

DAVECS1

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Not if it was properly cast and heat treated. The reciprocating force of the pistons is about 5 times larger than anything you can impose with a bolt or hammer.
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