exactly

 

Drive it like you stole it. The engine will be better for it.

 

i was a honda trans tech for 2 years... build moto race engines for myself, in my opinion break in should be constant changing revolutions, not one steady limit so the heat expansion is through the rev range... manufacturers IMO set those limits so that if something fails, it is not catastrophic to you or the car... kinda like a "see if it shakes loose" type bit. the manual states to consistently change revs.

 

It's more important on a new engine not to run it for long periods of time during break in. The rings set up fast, the wost time for them is at the intial startup.....galzing. Mass produced engines have a little tighter tolerance and need to work in/wear in the parts during break in periods because they don't machine all the parts to a high tolerance, they let them work in, cheaper for OEM. Race engines are machined to tighter tolerances and don't need to "work in" to get their intended gaps. So during break in you will get more heat generated by the parts as they work in. Don't forget, as parts get hotter they expand, and the gap tolerances go down. So you don't want to push it until those gap tolerances are set up and at high temps you still have the needed gap to maintain a good oil film which is what you need for slip.

Vary RPM is good during break in, just don't tac it to red line all the time and for long periods of time holding it at high RPM.......which is critical to have proper oil film layer between moving parts.

 

Varying rpm is the key, changes the engine temp often and allows for the expansion and wear, good advice

 

I was taught by a top drawer engine builder that if you baby an engine when it is new it will always run like it was babied. I actually drive the car harder when new than after break in....drive it like you stole it when it's new and it will run strong forever. Just one guy's opinion.........

 

Totally agree with this. I've taken test drives in MINI's and have taken them to redline with only 13 miles on the odo. I'm sure I'm not the only one whose done this, as the MA told me to "floor it".