Re: What 'break-in' procedure did you use?
it's not a joke. Although I don't recomend it, BonAmi has a long history of being used in other engines like large diesels, to help when the rings are hard to seat.
Not a handfull though. They would use the amount that would fit in a drinking straw, for a road tractor engine.
On some aircraft engines with chrome bores, the rings are very hard to seat. Specialsed machinery is sometimes used to work the piston in the bore with abrasive powder, to pre-seat the rings before engine assembly.
A very tiny amount(size of a pea) would probably not cause much harm to a HT engine, and might help seat the rings to the chrome bore.