What is the purpose of waiting until 1200 miles to go above 4K RPM? I don't know too much about cars but my friend who installs performance parts for cars says you should drive the car hard in the beginning so that the rings seat properly. He says drive the car the way you want it to perform. The only thing he says is to not keep it at the same RPM for a long time during the breakin time (i.e. cruise control down the highway for an hour at the same speed).

 

its debated, some say high rpms to seat them, some say the valves and pistons arent all seated properly and hitting them at 6600rpms is not good for them.

take what you will, all manufactures I know of reccomend a breakin, and those that dont break them in at the factory for you. I personally think those that build the engines should know best, and those that say otherwise are just impatient and this is how they justify their ways.

 

Who ya gonna believe: the people that build the cars or a mechanic?

matter of personal choice.

 

do it cuz the manual says do it.....seems like a no brainer

 

There's been a lot of arguments / discussions on this one through the years in various forums. I've read a number of articles on the subject and most of what I've seen implies that rpm, in and of itself doesn't make much difference. It's the load you're putting on the engine that does.

You can leave the car in first gear and gradually accelerate until the engine reaches red line and never accede 1/4 throttle because there's no load on the engine. OTOH, you can be cruising along at freeway speeds (70+) in 6th gear pushing a hard head wind, going up hill. Technically, you'll be within the break-in rpm recommendations but you'll be putting a pretty high load on the engine for a relatively extended time period. Which of these scenarios is actually harder on the engine?

What I've read that makes the most sense to me is, once you've got the first couple hundred miles on the odometer is to take an "occasional" second or third gear full throttle sprint to red line. Then back off and drive normally. The brief, but not sustained, loading of the piston and rings will help seat things in without allowing everything to heat up too much. I can't prove if this is accurate or not but it seems reasonable to me.

Having said that, the "safe" thing to do is to follow Nissan's recommendations. If you do, they can't say anything if you have a major engine malfunction. Anyway, that added 10th of a second improvement in acceleration to 60 that one break-in scenario "might" give you over another isn't something that 99.9% of us are going to feel anyway. It's your car, you make your decisions and take your chances either way!

FWIW!
Drive Safe,
Steve R.

 

Take the car to 6k, once a day after 200 miles.
Do not keep it at the same RPM for a long time either.
Always let the engine heat up first.

 

That's pretty much the strategy I chose. I gradually took it up to 6000 RPM after about 100 miles and I make sure to take it to 6000 every time I drive it. My engine is very comfortable running for any length of time 3000-5000 RPM and runs up to redline without complaint or hesitation.

I have a Track model. That's what I want.

 

Taking it easy on the engine for the first 1200 miles is done for the exact same reason that your friend stated for driving it hard: so that the rings seat properly. It was generally thought that if you push the engine early and mess up the rings, your car will be burning oil (leaking by the rings) for the rest of its life. But with the technology of today and the accuracy of the machines that build engines today, many think that this line of thought is obsolete and no longer necessary, but they still tell you this in the manuals to be safe than sorry... Then there's people like your friend that believe that if you push your new engine hard in the beginning it will somehow be faster after the break-in period. But I have never read or seen and concrete evidence of this personally, so I tend to view it as like an urban legend....

 

yes, thats actually the thought pattern I can most follow. no break in is required. running it hard or soft makes no difference in final performance. as engines are machined to such tight tolerances now I doubt much any "breakin" is required.

however I can understand how 1200miles of slow driving might be a better safe than sorry case, so I followed it, not so sure it helped me any, more that Im sure it didnt hurt.

my engine also has no problems hitting the high rpms.... obviously. itll cook along, I dont think being able to run at 3-5k has anything to do with breakin, any engine can do that unless its been downright abused.

 

You might try these links. Whether or not you believe them is up to you:

These two are related to motorcycles but the principles should still apply:

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

http://www.ntnoa.org/enginebreakin.htm

This one is related to Lycoming aircraft engines. Now, keep in mind that an airplane engine operates in an "entirely" different environment than an automotive engine but I should think that certain things would apply for both installations. Pay attention to the last two paragraphs on this one:

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

I'm not saying any of this should override Nissan's recommendations on the 350Z but they do give other points of view. I find the aviation (Lycoming) link above interesting from the stand point that an airplane pilot will likely be a LOT more interested in this than we are with our cars. If something goes wrong with his engine, he can't just pull over and park. It's interesting that they're recommending high power settings during the break-in period which tends to go against what we seem to be getting from the owners manual.

FWIW,
Drive Safe,
Steve R.

 

I have flown many of these Lycomings in the past and remember the same recommendations given to me on breaking in the engines "HARD"

I think the difference between an Aircraft Engine is tolerance to be honest...These Aircraft Engines will use on average 1 QT of oil at a weight of 20W50 in less than 5hrs of operation.

This is where the glazing comes in I think. Oil is always being burned or blown out the vents on these engines.

And they are air-cooled engines travelling sometimes quite quickly with a low power setting,ie descent. This has been know to cause cracks to form in the cylinder JUGS from Shock-cooling...They want you to keep the heat in the engine during the break in.

And above all the Aircarft Engine usually is running at a very high power setting to begin with...full throttle near all the time. And as you climb and the air thins, your power will drop to say 60% at cruise. This is not like your car's engine...in fact I'm sure if you held your car's engine at 100% power for a few minutes you'd be overheating or making metal...

The Tolerances of the A/C engine is the biggest difference I think...

I'm with everyone who says go a bit easy on your 350Z for the first while anyways as she cleans up the insides...I bought a new Honda lawnmower last year and the book said to change the oil at 25hrs for the first one...well I did it at ten hours and the oil looked like it had silver metalic paint in it...