There is such a thing as break in oil but it hasn't been used in about 10 years or more. You are right in that regular oil is fine and you should change it according to schedule. You don't have to worry about metal particles in todays engines - they fit with exact precision as apposed to the older cars that required a lot of settling in. On the older cars, metal filing wold appear as the break in oil did its job (this oil actually induced friction in order to properly "pre-wear" the parts - someone already mentioned this). However, I would not recommend synth oil for the first 5000 K's - that stuff has the opposite effect as break in oil.vaBooM said:Oil is oil.
There is no such thing as break in oil. If a manufacturer wants their cars to run longer on the same oil from the factory, so be it. Maybe their philosophy about it is all the parts internally generate shavings. Its possible they want those shavings to "hone" the valvetrain and such.
Doesnt sound smart, but hey, we follow what they say.
Re-build engines typically need a break in period for the reasons listed above and I think in todays world, that is where you will usually hear the term "break in" more often - anything from the factory is good to go (although I wouldn't drive the piss out of it for the 1st 1000 km's or so - IMO)