Actually broken a rod or a crank?
I'm not talking about something like hydrolocking and bending a rod or losing a rod bolt and then brending a rod.

Mostly, I want to hear about the crank, but also the rod. I just cant see how a crank breaks before the rod bolts let loose or the main bolts give way. Same thing with main caps.

My friend and I were talking- we've never seen a broken main cap or crank as the SOURCE of engine failure unless it was something a stock crank and rods on an 8700rpm beast.

Somewhat related, we also dont understand, when it comes down to metallurgy, why billet cranks are stronger than forged cranks.

 

We have a 5.3L sitting in back here that was in an 07' Tahoe that broke the crank.

 

stock? can we assume manufacturing/assembly defect or simply overpowered and weakest link?

 

i wouldnt say weakest link; atleast not if it wasnt a huge, high hp engine. these cast cranks have rolled fillets for additional strength as they lessen the stress on the crank.

 

well, if it broke first, it was the weakest link

 

im speaking in general, as in manufacturing defect!