Quote:
Originally Posted by nachob
This is correct. I worked for an IMSA GTP team in the dyno breaking in motors before the races. Be mindful of varying revs, keeping under 4000 RPM and even after break-in do it gradually. Be mindful of heat cycles too; You will need a few times of letting it cool completely, then bring the motor up to temperature. You can get the rings seated pretty well at operating temperature but they can be tight still during cold situations, so will need a few cold-operating temp cycles through in there so that the rings and bearings seat throughout the entire range. Most cars use different metals in pistons, rings and cylinder liners that have different expansion rates. That is why you raise the RPMs for a short duration bringing up the engine temp, then back off to let the thermal load dissipate, then push it again and repeat.
The one variable here is that I believe BMW is not using steel cylinder liners anymore but some coating on the engine block but you will still experience different thermal rates regardless.
Congrats and enjoy.
It is heartwarming for me as a car guy to see other guys caring about break-in. So many don't anymore, they have bought into the myth of breaking in a car like you stole it. I also recommend you change the break-in oil at 1200 miles as well as M diff and I personally would even do the gearbox at 1200 miles. In the 1M it was specified by BMW engineers but after there was a shortage of the then special MT5 fluid, BMW USA, changed the maintenance schedule and made it optional. The rest of the world where the customer paid for their gearbox fluid, BMW recommended the transmission fluid change.
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Agree with the above. Also, this was the norm in the E9x M cars as well. There was a bulletin sent out to ensure that engine, diff, and tranny fluids were all flushed and replaced.