Leak down/compression test to determine if there's valve damage.

If not, set timing and count lucky stars. You should have definitive errors related to over retarded cams both intake and exhaust if the crank slipped. (even if no errors, on setting timing it will show). It is crazy this motor isn't keyed at the crank, but the incidence rate is not high makes me wonder if people are reusing crank bolts and being surprised later. Do you know the engine's full history?

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)