chuck911

Well mine was broken in with many full throttle to redline accelerations in the first 200 miles, and now 120,000 miles later it still uses only about half a quart per 5,000 miles. Exactly what I have done with all my cars and rebuilt engines. This is why my first advice is to study logical fallacies first. "Well I tried this and this happened to me" is not an argument. And I'm not seeing anyone claim that babying it per the factory is harmful. (It may be, in the long run, but not by much.) The question is, is it necessary? There's not much evidence that it is.

Huncowboy

I am just writing this, because it just popped into my mind while I was reading chuck911's post about riding the car hard on the first 200 miles. When I used to be a flight instructor (quite some time ago), I remember once they gave me an airplane that had a major engine overhaul. I was supposed to break it in by flying it around at a constant high power for a few hours. This was to seat the cylinders. Here is an article about that if anyone wants to read it http://www.avweb.com/news/maint/1828...l?redirected=1

I am not claiming that airplane engines are similar to a 911's in any way. But that is what you do with a new engine in a small general aviation airplane. So I find chuck's theory interesting.

Our 911 is around 600 miles. But I just had to stop driving it because there was no way I was going to stay under 4000 rpm. On top of that ours is a short 27 month lease. So I have no idea why I care, except that I love cars, and I just can't be rude to this beautiful peace of machinery. Not yet.

But chuck might be onto something. Still I think I will just do the recommended 2k starting to gradually increase from 1k up. I wish I had the time to take a 2k trip with it, but I did not.

alexneo

It really depends on how the engine is manufactured and the tolerances involved. Newer engines are far more reliable than previous ones. And usually failures occur on the ancillaries (belts, pumps, etc) rather than a piston or engine block failure.
IMS failure on the 996 (M97) is a good example of bad design and break-in didn't really help. The point is if your engine has a manufacturing defect, a proper break-in won't save it, the warranty will...
I generally believe people are overreacting on the topic.
Again the same service manager told me that the newer engines (MA103 and MA104) are virtually indestructible, easily going well over 150k miles without major rework.
Logically, if the break-in during the first 2000 miles was so critical to the engine, I sincerely believe Porsche would've done it themselves in order to protect warranty claims within the first 2-3 years.

clutchplate

The proper break in procedure for cars that are purchased is to not exceed 4k rpms during the first 2,000 miles.

The recommendation for cars with short leases it's to never get below 4k rpms.

golftime

Let me first say I would never recommend not complying with Porsche's recommended break-in procedure. That said, I can provide some anecdotal if not scientific information regarding this issue. I previously worked for a large law enforcement agency that bought hundreds and hundreds of police vehicles. Granted they were not Porsches. Out of every purchase, a percentage of vehicles were lettered and sent to patrol, and others were assigned to detective work and other non-emergency functions. The patrol cars were run very hard right out of the gate - lots and lots of full throttle, often while engine was still cold. The others were run more similar to everyday cars with limited hard driving.

At about 25-30k miles the difference became noticeable. The patrol vehicles were clearly quicker. Lots of snap throughout the range. I never noticed any more engine failures or other engine problems, i.e. oil consumption with either group. In fact the other parts that had limited life spans seemed to fail at about the same mileage in both groups. The fly in the ointment is that the cars were generally off-loaded at about 100-125k miles, so it is hard to tell if the complete lack of break-in ever caught up with the patrol vehicles, or maybe it was just a testament to the durability of both Ford and Chevrolet police vehicles - very impressive. I am not sure this settles this discussion (or makes it worse) but I think about it whenever the break-in question arises.

ML911

Was just looking up something in my German manual for another thread and stumbled on a break in section in there as well.

They recommend for the first 3000 km:
- to favor longer drives
- to avoid lots of cold starts and short runs
- to not participate in Clubsport or other track events
- to avoid high revs, especially when the engine is cold

So the break in recommendation seems to be not just for the US.

chuck911

Thanks, but its not just me, and I can't even take credit for it. What follows is my take, assembled from many hours of research, conversations with some accomplished technicians, and much personal experience.

Unlike the factory recommendation, which is based on (if anything) liability, the "run it hard" break-in truly is as you say, a theory- or more correctly a recommendation based on a theory. I'll take theory over superstition any day!

The theory goes like this.

All the moving parts in modern engines are designed and manufactured to such a degree as to eliminate any need for break-in. With one exception: the piston ring cylinder wall interface. Everywhere else where working parts interface the surfaces are machined to near perfection. Cylinder bores however are honed to achieve an intentionally rough surface.

A rough surface is necessary in order to retain just enough oil to prevent piston seizure. This roughness, however, presents a problem. In order to develop maximum power the rings must seal well with the cylinder wall. The roughness allows gas to escape, a loss of power. It stands to reason that the better the rings are seated, the greater the engine's power will be.

Now creating this rough honed surface produces not only in the desired oil-retaining fissures, but also results in a patina of much smaller ridges and peaks. These micro-peaks are so fine that they will soon be worn down regardless of how easily the engine is run. The time this takes- a few hours, at the most- is our window of opportunity.

Piston rings have springs to press them against the cylinder wall, but these springs are not the main force creating the seal. Pistons and rings are designed to channel combustion pressure to press the rings outwards against the cylinder. The greater the throttle, the greater the power output, the more the pressure.

And these are incredibly hard materials we're talking about. We need a lot of pressure. To seat the rings. That's what its all about.

If the engine is run easy the rings will glide up and down and the cylinder wall micro-edges will wear smooth - without ever encountering enough force to have caused the rings to seat! But if the engine is given lots of full power use then this vastly increased pressure will push the rings into the cylinder wall with such tremendous force that those tiny peaks will be virtually filing material off the rings, fully mating them.

What are the benefits? Improved ring seal equals higher power output. I prefer knowledge and understanding over stories, but can't help noticing how perfectly this agrees with golftimes story about the police cars with "complete lack of break-in" being "clearly quicker" and having "lots of snap throughout the range."

The only thing left to say is its not the cars that "were run very hard right out of the gate- lots and lots of full throttle" that had a complete lack of break-in. Its the cars that are driven part throttle for thousands of miles, as the factory recommends, that are not being properly broken in. Once we understand what its really all about then its easy to see that lots of full throttle in the first hundred miles is, in reality, the correct break-in procedure to follow.

chuck911

OMG! I wrote my post BEFORE reading the article Huncowboy linked http://www.avweb.com/news/maint/1828...l?redirected=1
Great stuff. I think this guy has it exactly right- "if the engine isn't broken in at 10 hours, it just isn't ging to happen...But if you do the right thing during those first critical 2 or 3 hours of break-in, you'll get good ring seating and low oil consumption every time."

SkandoSchwabe

Interestingly my Jeep manual tells me to run the engine at various rpm with occasional full throttle excursions to redline for the first 200 miles. This seems to be somewhat in line with the above.
On the other hand, why would Porsche recommend a break in proceedure that would give suboptimal results and increased oil consumption?

kayjh

Also, it isn't just the engine that needs to be broken in. What about the internal parts of the transmission and differentials. These are all expensive components that need some running in time, as per the owners manual (NA). If you get the urge to wind one out. Why don't you just go back to the dealership for a wash and take a demo out for a 1/2 test drive??

chuck911

Every part in a brand new engine, transmission, differential you name it, has already been designed and machined to as high a standard as it will ever get. From this point on all any of these parts can ever do is wear and degrade, becoming further and further out of spec, until the day they eventually fail. See Entropy. Therefore, in all the lifetime of an engine (transmission, differential, you name it) there will NEVER be a time when it will be more capable of being run wide open than when new.

But again, the one special case is seating the rings. Every other part, it really makes no difference what you do. But fail in the first few hours to use enough power to seat the rings, well then it doesn't matter what you do, the opportunity is gone.

Key Left

How about cylinder top ridge rings or bumps? You must stretch the rods at the proper time to avoid forming these as they are the ultimate ring busters. We broke in per Porsche and observed the 4200 rpm limit for 4K and have only done long trips. We are at 9K since mid -June and our M104 has gone from clattery at idle to whisper quiet today. Follow the directions folks, Porsche management isn't steering you wrong.

Key Left

Errata: 4200 rpm for the first 2K, that is.

chuck911

The ridge you're talking about only develops after extremely long use. Even then, its important to THINK about why and how this might happen at all. If an engine is run its whole life, 150-200,000 miles at near idle then yes, the lack of high-RPM forces can result in uneven wear that leaves a ridge of relatively unworn material at the extreme top of the cylinder. If this engine that has been babied its whole life is then suddenly at 150,000 miles revved to redline its possible the rings contact that ridge and break. (Even then not likely, merely possible.)

Its not clear to me what the story of a one in a million 150,000 trips down the block to church driver has to do with the need for rings to be seated during the first few hours of use. Its even less clear how this relates to a new car with less than 9k miles on it. And if preventing these ridges is so important, then wouldn't it make much more sense to redline early and often? The longer you wait, the bigger the ridge, right? But this gets back to my very first point, the need to study logical fallacies before even attempting this subject. When I said this alone will eliminate 99.9% of the reasons for following factory break-in, I was probably being conservative.
http://utminers.utep.edu/omwilliamso.../fallacies.htm

bccars

I think I agree with KeyLeft. My engine felt very coarse, restricted and vibey the first few 100km. I can't imagine what damage I would have done would I have not taken it easy back then ! If something doesn't feel smooth, to me logic dictates not to force it !