Mineral Based OIL

Why I have to use Mineral Based Engine Oil? Is there an other advantage otherwise it is cheaper? I couldn´d find any Mineral Based 10W60.

For?

I believe Walter is talking about break-in procedure. The thing is that synthetic oil usually has better friction properties comparing to mineral oil which isn't what you want for breaking in the engine when you have very narrow window to bed in piston rings against fresh hone on cylinder wall...

That's why Manley, Mahle, Total seal, BC don't recommend synthetic oils for breaking in...