[CA330i]

Hi OZ, thanks for the reply. I don't believe that the issue of whether or not synthetic oil is suffecient for break in as opposed to dino oil has ever been discussed here. There has been plenty of discussion regarding when to change the synthetic oil though. To me that is clear... 1200 miles to flush out shavings etc.. My question concerns the initial (and all important) <50 miles when the piston rings seal. It has always been my understanding that dino oil is superior to synthetic in that regard when it comes to sealing the rings. I would appreciate any thoughts on dino v. synthetic during the short but vital break in period.