I'm already at 1200 KM's on my 2017 in two weeks (LOL). I am trying very hard to keep it under 4K for the first 2000 km (1200 miles) but I have been disciplined.

I Plan to do oil and filter change at 2000km (Nissan oil and Filter) and cut open filter and check for proper amount of metal. Then go another 3k and change to Redline 5W30 and K&N or WIX XP filter.

Another good break-in suggestion people have forgot to mention, is to TRY and prevent stop and go traffic and long idling.

Most important is vary the speed on highway. I've ran all the way to 6th.

I've been driving for over 45 years, and I've always broke-in the car the way that I would ultimately drive it. However, I would never red line it or try and lug the engine. In all these years, I've never experienced any excessive oil burning, or any other internal engine component failures. I think the key is to change RPM levels on occasion. All of this helps to seat the piston rings and that's what the break-in actually accomplishes.

Is it really THAT important? What does it improve?

Mr. Engineering Explained also doesn't clearly mention any technical details on this point.

My Grandpa would always do a hard break in along with giving it hell on the test drive :icon17: so I ultimately drove my Z like I do now without following a break in - not that I was redlining it all the time though. The engine has already been run in at some point along the line.

That's just about verbatim what the dealer told me when I got mine last spring. Heck I had it up around 7k rpms on my test drive with all of 62km on the odometer lol

I did change the oil over to synthetic by 1000km and put in a magnetic drain plug to catch any debris from break in.

Mine was broke it by the time I got home from the dealership!:ughdance:

Modern cars are built to much better tolerances than those of yesteryear and don't need the same treatment. If we were talking about a rebuilt engine...that's a different story.

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My background is Aviation. Air cooled, Piston, N/A aircraft engines are completely different beasts. They are nothing more than large lawnmower engines. Relatively speaking.

Having said that, they are still engines with pistons, rings, valves, camshafts and bearings

To put it simply without too much technical explanation:

avoid travelling at a single speed or RPM for prolonged periods since varying engine speeds are vital to proper break-in as they expose internal parts to a wider range of heat, pressures and stress. (notably the piston rings.)

In todays cars, I'd narrow down to the two more important important terms: Pressure and stress. Heat should not be an issue in a proper Water cooled system. (unless of course you decide to break-in really hot weather.

That brings me to the next argument. The 4000 RPM for first 1200 miles is Determined by Nissan to cover a wide range of users and climates and scenarios

It assures proper break-in, without overheating or excess wearing if conditions become extreme.

Thank you all for your input!

This is the only point that was made to me by a lot of folks that know more than me!

Just be sure oil temp is up to 180* or close to it before twisting it's tail!
They normally cruise around 200*F,,,which is normal!

I've broken in many motorcycles and believe in a hard break in. Varying Rpms whenever possible

Just dont keep it at a high rpm for long periods. (cruise at 5k+rpm on the highway)

I don't believe break in periods are that critical anymore. Manufacturers still put it in owner manuals more as a best practice. Personally, I just drive the car normally. I don't flog it nor do I baby it. I've never had any issues with any new car I've owned.

You would think that if break-in periods were critical for engine reliability and longevity, car manufacturers would program lower rev-limits into the ECU for the first couple thousand miles or so.
I wouldn't worry about it with modern cars. Of course, common sense has to prevail. If someone takes a car from the showroom floor straight to the track, that's pushing it.

I agree. I still think you should take it easy for a few hundred miles tho. Just to be safe.

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Don't forget, you are also breaking and seating the gears in the transmission (if MT) and the ring gear and pinion and spider gears in the rear end. It's probably best to vary the speed, temperature and torque on those items. But, hey, this is America. It's your car. Do what you want.