Debunking myths: Follow the owners manual?
In respect to the earlier 1st article - Motoman's logic (mototuneusa.com) - about 300 rebuilds & running motorcycles/snowmobiles, someone decided to investigate this with GM, Ford & Honda engineers to see what their opinion was. Bear in mind motor vehicles heating & cooler is not as pronounced as that of a motorbike or snowmobile:
Car & Engine Performance - Technologue Editorial - Motor Trend
Here is another article about running in a aeroplane that takes consideration of cool air and giving the motor some intermittent load occassionally:
Engine Break In - Shell Aviation
Glazing in a nutshell:
Stealth 316 - Engine Break-In
Synthenic oil use & break-in:
Synthetic oil during engine break-in? Here's what the oil manufacturers say... | Roadcarvin Magazine
Old school break-in:
How to "Break-In" Your Newly Rebuilt Engine
My considerations for running in a motor: Load, Revs, Air-Temp & Humidity, Gear Ratios & Speed.
Thrashing the vehicle in lower gears revs the motor, but does not neccessary load it up as the lower gears allow the motor to spin up easily. Higher gears, like 4th gear that may be around 1:1 will make the motor work harder per revolution of rear wheel drive. Important not to labour the motor with too high a gear at lower speed limits (60kph). Higher speed limit will allow for higher gears & therefore higher load on the motor, without over-revving with the advantage of more cool air hitting the intercooler/radiator/engine. Similar to riding a bicycle in its lower gears, peddling fast, but not going anywhere is not that difficult on your legs. Labouring the motor would be like being in too high a gear on the bicycle & when trying to ride up a hill - not good either. Staying in a higher gear at faster speeds should ensure the motor relies on torque rather than power, therefore creating higher loads, help forcing out the piston rings - everybody loves a torquey motor. Nobody likes a speeding ticket. RNP and Old Pacific Hwy around Brooklyn Bridge have many deaths, albeit most are motorcycle deaths; these areas are very much patrolled.
Cheers.
WJ