broken crankshaft

[Dzchey21]

Got it out finally but unfortunalty I didn't have the luck I was hoping for. This one spun the center main bearing so it's going to need machine work. Probably just going to order a long block

 

[B585Ford]

Sorry to hear that the damage was more than you were hoping for.

 

[tbsimmons]

Do you guys think this is a material flaw?
I was thinking that can it be the stress of regen on the back 2 cylinders.
Then expect more power out of it. Hell I dont know. Seems weird thouhgh

 

[Dzchey21]

No big deal he's going to do a reman

After reading some more of my failure analysis books it looks like the cracked started on the fillet of the main journal the two outer bearings have weird wear on them like the crank might have been slightly out of round I'm going to send it to our failure analysis group and see what they say and donate it to the class material

 

[tbsimmons]

Could the crank have walked some and the end play being too much.

 

[Dzchey21]

The thrust portion of the bearing looks pretty good suprisingly

I can't decide if the main bearing spun because the crank broke, or if the crank breaking and the bearing spinning is a sign that the crank was either bent or the line bore was not straight from the begining

 

[tbsimmons]

That would be hard to tell. Post up after you fun the analysis. That would be interesting to see.
Are the known ones broke higher rpm trucks. When you put it back together thought about nitrating the crank?

 

[Stroked777]

What's the serial number on the block? Maybe other people with broken cranks could post there serial number as well to see if there is a pattern. It's weird that two broken cranks popped up with in a week and I never seen a broken crank in these before the recent two

 

[Dzchey21]

This truck is bone stock, dually with 4.10 gears,

I havent had a chance to send the crank up just yet

 

[dohcter]

Interesting. Exactly where mine broke. Had a machinist look at mine and figured it was either a flaw or was dropped at one time. But this might be anther issue since there is more then one that broke in the exact spot..