engine rebuild
 

I am considering the purchase of an 1984 930 .The engine was rebuilt and a new crankshaft was installed.I have very limited knowledge of these engines .Should I be concerned that the crank needed replacing.

There are plenty of things that can go "bang" inside the engine where the crankshaft could be damaged, such as a spun rod bearing.

I wouldn't be specifically concerned about the engine getting a new crankshaft, but would be concerned about the overall quality of the rebuild.

I am in the process of rebuilding my '79 right now. During disassembly, I was surprised to find evidence of a prior rebuild...and it appears to me that the prior rebuild was not very well done. I have no idea why it was rebuilt, but I don't think that they properly cleaned things as I found scoring on the crank and rod bearings that indicate there was debris in the oil system.