You said they machined your crank yeah? did they drill out you oil gallery caps and flush it out? you can tell if they have they tap the holes and fit little grub screws
It may have puched metal filings through the engine. Did you also remove the spark plugs and fuel pump relay and turn it over until you achieved decent oil pressure before you started it? (may take a good minute or two to get oil pressure while cranking). Just thinking they may have been a little oil starvation issue on start up otherwise.
