Okay, so lets recap a little here...
My recommendation (as presented earlier in this thread), which was attacked by Mr. JulesMaximus as "horrible advice"
-drive car around the city with liberal use of throttle, but nothing crazy. This is to provide some load to the rings to help them seat.
From the Mazda owners manual for the Mazda 3:
- NO special break in is necessary, but a few precautions for the first 600 miles
- don't race the engine
- vary speed
- don't drive at constant full-throttle for extended periods of time
-avoid unnecessary hard stops
-avoid full-throttle starts
-don't tow a trailer
Honda automobile break-in process is thus:
-Avoid full-throttle starts and rapid acceleration. (NO limit on engine speed)
Nissan break-in process is thus:
-Avoid driving for long periods at constant speed, either fast or slow, and keep rpm's down to 4000 or lower (2/3's of redline).
-Do not accelerate at full throttle
-Avoid quick starts and hard breaking
-Don't tow a trailer
Ford recommends:
-Your vehicle does not need extensive break-in.
-Vary driving speed frequently (NO limit on engine speed)
Anyone notice a trend here? Basically, just don't thrash the stupid engine and don't drive at constant speed.
In addition to my recommendation, which in NO way violates what Mazda (or any of these other manufacturers) suggests, I commented that vehicle manufacturers that suggest an easy break in (motorcycles mostly) are influenced by the manufactures encouraging the user to become familiar with the vehicle before using too much power. This part is somewhat my opinion, but it's a well considered one. I'm a mechanical engineer that worked for a automotive OEM for 21 years and I've personally rebuilt at least 20 engines with my own hands over the years. I have good friends that work inside OEM engine assembly plants and we talk about this stuff. Oh, and I've been riding motorcycles since 1979 and have just completed a top to bottom restoration on an older Kawasaki 750.
It's dumbfounding that anyone with any mechanical savvy would argue against what I've said but hey, this is the internet so there you have it.