This subject was discussed at length in this thread:

https://my350z.com/forum/showthread....&threadid=3120

There were a lot of opinions and experiences but no universally agreed-upon conclusions. The discussion did include a link to an aircraft engine manufacturer (Lycoming) that recommends full-power cycling like N74DV mentioned and the technical reasons why they recommend it, and there are also recommendations by Raceboy, the go-karter mentioned above.

If you are interested in this subject, I recommend that you take the time to read the whole thread, then make your own decision.

 

I have read that technical document by Lycoming and others by Franklin and Continental... they all pretty much say the same thing.

DO NOT BABY THE ENGINE.

They say to pretty much run the engine the way you intend to run it the rest of it's life. Don't be hard on it but don't baby it.

Thats how I broke in my 350Z. there were several times once I hit 500 miles where I raced it for a 1/4 mile floored.

I also ran it on the highway for several minutes in a gear lower than normal to keep the rev's high.

I say Nissan is just covering thier *** for the dopes out there who won't use good judgement.

IMO by all means..... run your Z a bit harder than you think you should in that first 1200 miles.

Thats what I do in aircraft engines...... haven't had an aero engine fail on me yet (knock on wood)

 

Airplane engines are considered "industrial engines," which basically means that the build quality and life-span of the engine is way beyond any car engine. Basically, airplane engines (and tractor engines & semi engines) are built to extremely tight tolerances, and their life-span is measured in tens of thousands of hours. As opposed to car engines, where a 200k mi engine would have about 5k hours. Also, airplane engines are rated at 75% max power: they can cruise at 75% throttle indefinetly. Try doing that with a car, and you will slag the thing.

As far as I know, the "break-in" period has to do with seating the valves and valve-guides. This was more of an issue with older cars, where there was a fair amount of play between the valve and it's guide; you had to be nice to them until enough crud got caked in there and sealed up the extra room. In newer cars, the amount of room between the valve and the guide is much less, so the break-in period is shorter than it used to be. I would guess that since the tolerances in an airplane are so close, there isn't much need to do a break in, and the revving is for some other benefit.

 

I just read the Lycoming engine break-in page at:

http://www.lycoming.textron.com/main...neBreakIn.html

which states that the high-revvs is to seat the piston rings. But is also defines "high-revvs" as between 65% and 75% power, not 100%. Based on that info, I'm guessing that when Nissan says "vary your RPM," they are trying to compromise between the high-revvs that the piston rings need and the low-revvs that the valves need. But that's just a guess.

 

118 MPH doesn't sound like a gentle break-in to me. I've kept mine below 85 MPH mostly, and went 90 MPH once or twice.

 

Just passed 1,000 miles - only 200 to go until I can rev this baby out! I've been following the recommended (owner's manual) break in - kept it under 4,000 rpms for 1st 1200. Well, I did get carried away once...

Looking forward to winding out the tach a bit more than 4,000 however. And I'll set that rpm idiot light to about 10,000!

 

The manual says nothing about limiting your speed, but limiting your revs.

 

I think I cheated about 4 times but never went of 5500 rpms. I already had about 700 miles on it and I wanted to know what it would REALLY do. 2300 miles now and am still having fun.

 

Nope, too little time and too many speed limits to break.

P.S. Took it up to 230 Km/h the night I took delivery (10/29/2002)

 

I will break in my Z a week after i get my Z! DECEMBER 23RD!

 

Well with 800 mile on it now the the rev limit has been hit a couple of times but a touch and go through the gears. The most important thing would be NOT to set the cruse control and just set there. Putting the miles on is one thing but holding it at 2300 rpms for 1200 miles is harder on a new engine than 7000 rpms . A true breakin is just that working the engine at all rpms.

Did find something that I didn't like last night, wheel hopping when I hit 2nd in a turn. But the Gs feel great on a circle enter ram for the expressway. It holds the outside line at ___ mph 4th gear.

The fun with this thing is not the long straightways but in the turns.

 

Could you please explain to me the definition of wheel hop?

Thanks!

 

Have you ever seen dragsters taking off, even in video? The rear drive wheels lose traction and spin and smoke. You may remember seeing the rear of the car hopping up and down before the car settles down and starts moving forward. That's wheel hop.

As you can imagine, when you're hopping around you're losing time and acceleration and especially control. A nice even spin is still loss of traction but it's better than a hop. This guy's talking about a wheel hop going into second gear in a turn. Not fun!

 

The way that I ment the term wheel hop was related to hitting 2nd in a turn and the rearend was braking lose, not sliding across the pavement but hopping.

It only happened for a second and there was not a control problem. My only thoughts are that the traction that the tires have and the angle in which I was traveling allowed to brake lose but not lose total traction and smoke like the cars that I have had would.

 

Break-in Period

 

You're averaging 1/2 a post per day and this is the best you could come up with?

 

My brother and I both bought 1997 Chevy C1500 Ext. Cab trucks with a 350 and Auto. I swore by the easy break-in. He is a little more unorthodox. Other than warming it up, he drove it hard. It may not have been full throttle every time, but usually around 3/4 to 7/8. His truck was only 1 week old when he took it the track for the first time and it ran a 15.7 his first try. Mine started to fall apart at 100k. There was another site that someone else posted that explains why the "hard" break-in is the best.

http://www.mototuneusa.com/break_in_secrets.htm

 

No offense, but that's hardly a fair test. First of all, two "identical" vehicles are always a little different. Plus, you probably didn't keep up with what was done to both vehicles to maintain them over the 100,000 mile period. Perhaps he maintained his better or something, etc. Did you guys test them on the track or a dyno later? Finally, it's hard to make a curve out of only one data point.

WayneTN

 

I know that isn't definitive proof but it's a nice anecdote. Please hold all flames(people like trucks in Texas in case you didn't know) but everyone that rode/saw his truck swore it was the fastest that they had seen. After he put his bolt ons he ran a 14.9, which is unbelievable for a stock motor Ext Cab Chevy truck. It actually seemed to accelerate faster from 50-100 than it did from 0-50. I know that I can't say that his break in was responsible for his extrordinary performance but I can't help but think it was at least partly responsible, especially after reading Moto Man's website. Oh and he definitely didn't maintain it better, I always ran Synthetic after the first 2 oil changes. He was doing good if he changed it every 7500 miles.