Had a discussion at field about correct engine breakin procedure, encountered considerable range of opinion. I recall reading that for ABC, need to get engine up to operating temperature and that running rich and slow would just wear out the engine. Ringed called for temperature cycling, that is, running 1 minute at operating temperature, then stop and let cool ( or alternately richen up to cool it off ). Curious what "experts" say in this regard, we have many at our field with wide range of opinions. My experience hasn't been particularly broad as am partial to the plain bearing ABC(N) like OS FP series, usually just run them on rich side with castor blend ("break in" flying) and don't worry too much.