Quote: I'd reserve all judgement until the problem is found.Like what has been said,be there as it is being dis-assembled.Don't be surprised if some thing is found on top of a piston.Do you have or have access to a borescope?Do you know which cylinder is near the top of it's stroke when it locks?You can determine this by turning the engine until it stops,back it up and put your finger over the plug hole to feel pressure. Also if it's a blower motor,check your pully bolts on the front of the crank and make sure one is not interfearing on the timing cover.Check the same on the blower.
everyones always so quick to pass judgement.
When you spend nearly $4500 in parts, and pay an engine shop $1500 for machine work, assembly, clearancing, etc. you tend to get a little jumpy when something's not right. If I'm going to spend $6000 on an engine build, that's something I don't want to do twice. I know everyone is human and we all make mistakes, but you have to wonder, if they missed something simple, what else did they miss? (that is, unless it was your fault because you dropped a nut down the intake or whatever)
Also if it's a blower motor,check your pully bolts on the front of the crank and make sure one is not interfearing on the timing cover.Check the same on the blower. 
