help please! crank has broken

[565bbchevy]

Did you get the rotating assembly balanced with the new pistons?
R. I believe not.
Did you use the crank bolt to turn the engine over or a crank socket?
R. Guess not.
Did you use a balancer installing tool and how smooth did the balancer go on?
R. I believe Yes.
Did you see any other damage to anything when you tore it down?
R. The engine is not revised yet, but apparently it was only the crank nose.

I have no experience to build an engine, so i sent the engine to a mechanical service workshop, where is assembly the engine finally.


Pd: Sorry for my English, it's not very good.

If the only damage was the crank snout I would buy a new crankshaft and have it balanced with the assembly and I would also get a new balancer and have your builder make sure it has the correct interferance fit and use the proper balancer installation tool.
The best way to turn the engine over during assembly without the balancer installed is with a crank socket so you don't have to put added stress on the threads especially on a used crankshaft that has been disassembled a few times.

 

[79wagonator]

I had the the same exact thing happen to the crank on a new gm crate 350 in my camaro years ago.
Because I reused the old balancer from the original motor that i grenaded.
I had felt a vibration when I revved it up before that happened. Didnt know why? (young and dumb..)
I'd wonder How is the bolt there in that pic not damaged??