Questions about swaping my crankshaft

[DawgMode]

Alright a couple weeks ago i destroyed my Crankshaft main bearings and connecting rod bearings which cause a bad knock. so i pulled the engine and found out that i scorched my Crank. So now i found another crank from a memeber on this site which i am going to buy off of him in good condition. But then last night i had a friend tell me that it is still going to knock with all new bearings and unscorched crank.

Is this true what he saying and why???

p.s anybody know a place that can repolish cranks and how much does a polishing job cost?

[yellow_jacket]

You just need to get some plastiguage and check the clearances. If the rods and mains are scored though, you will need to tear the motor down and get everything polished.