Can someone please explain engine break in period?

[49er]

Thanks Footy for sharing your experiences in regard to the running in process.I found this info very helpful, as I'm sure many others will.

There is always debate on which running in oils to use, mineral or synthetic. Many of the additives used in either seem to be responsible for slower
removal the asperities between the rings and bores. I use a 30 grade mineral oil myself.

It is quite important to emphasise that reline rpms are to be avoided during the first 500 miles, especially on a high compression air cooled engine. Excess heat build up will do ring damage and defeat the bedding in process. In extreme situations such as minimal piston to bore clearances, seizures can result.

[chef1366]

It is quite important to emphasise that reline rpms are to be avoided during the first 500 miles, especially on a high compression air cooled engine. Excess heat build up will do ring damage and defeat the bedding in process. In extreme situations such as minimal piston to bore clearances, seizures can result.

Oh Drat!
...