In my opinion there are thousands of factors that one must consider when properly "breaking-in" a motor. To me the single most important factor is piston ring expansion.

A good break-in requires that the piston rings expand sufficiently to seat with the cylinder walls during the engine break-in period. This seating of the ring with the cylinder wall will only occur when pressures inside the cylinder are great enough to cause expansion of the piston rings. Pressures in the cylinder only become great enough for a good break-in when the engine is running at or greater than 65-70% power. Therefore, to me, it is imperative to "Drive it like you stole it" At least part of the time.

Although every car is different, I'd recommend following whatever is outlined by the engineers in owners manual. I am not certain, but if I know Infiniti/Nissan there is definitely something in the owners manual regarding break-in periods.

Just a thought,
BC

 

You don't necessarily need to rev it to high rpms to get the increased pressure you are looking for. By simply gunning the engine while keeping the rpm's under 4k as suggested by the manual, you will get the same compression rates (faster rpm's are the result of the same increased pressure maintined for a longer period of time). The higher rpm's are tough on the moving parts of the engine prior to them being "broken in." The higher compression at lower rpm's is the torque we all want so badly.

 

G8RDave, do you mean keep it at 4k just in different gears?

The only consistent thing I've ever heard about a break in on any car is don't keep it at the same rpm for long. I have about 1k on mine and although I havent redlined, I beat on it here and there. Also, I lease, but I treat it very well.