SiNi

Scientific arguments aside, after a bit, break in sucks!

To quote Gary (from memory) - "break-in is like saving yourself for marriage"

That pretty much sums it up. Only 350 miles to go!!!

chuckbdc

Only 350? Send a message to Gary. He is understanding and will probably grant you a waiver.

chuck911

Dreamer, your last line is a definite keeper.

And no, you are not wrong. At least not in my opinion.

I'm sure you had no idea of the pot you were stirring, let alone the contents bound to boil over. A claim I'm not able to make, but even I've been surprised myself at what got stirred up. Oh well. Your question, "WTF AM I SUPPOSED TO DO?" deserves an answer.

But first, a little background.

Much like you, I'm also expecting (okay, HOPING ) to be buying a new 991- in my case with Euro Delivery. Its a lifelong dream. You will find here lots of guys with multiple Porsches, that's not me. Just the one is a huge financial stake. So this is for me a Big Deal and something I am determined to get right regardless of the effort involved.

That said, I've no dog in this fight. Like you, I started reading just trying to learn as much as possible. This was one of the subjects I wanted to understand better, but I never raised it myself, and when it did come up for the first time (for me anyway, I later learned its been percolating forever) I merely asked if maybe modern manufacturing improvements have given reason to rethink the problem. Thankfully some thoughtful RL'er posted this link http://www.mototuneusa.com/break_in_secrets.htm



Unfortunately, these articles are written in Motomanese, an obscure dialect of Tripe he may have picked up from excessively watching MTV. Its a shame, because these articles taken together contain all the information you will ever need to answer your burning WTF question. And so I will translate for one and all.

The first article begins with the rather uncontroversial observation that manufacturing technology has improved. Engine manufacturers now use a much finer honing pattern in the cylinders than they once did. This in turn changes the break-in requirements.The window of opportunity for achieving an exceptional ring seal is much smaller with newer engines than it was with the older "rough honed" engines. In addition, there is a lot less heat build up in the cylinders from ring friction due to the finer honing pattern used in modern engines. Other factors that have changed are the vastly improved metal casting and machining
technologies which are now used. This means that the "wearing in" of the new parts involves significantly less friction and actual wear than it did in the distant past.

Okay, I lied. That wasn't translated. It was cut and paste. This is what's caused all the commotion? Go figure.

The remainder of Part One simply delves into this much more deeply. Piston rings rely on combustion pressure to achieve their seal. The springs are there to wipe oil but provide too little pressure to seal against the powerful combustion. So rings are engineered to channel combustion pressure into pushing the rings against the cylinder wall. The greater the combustion, the greater the pressure- and seal.

Already you can see the problem with taking it easy. If you are practicing Critical Outside The Box Thinking, that is.

Finally he gets to the "WTF DO I DO" part!

1) WARM UP THE ENGINE COMPLETELY. (He actually puts this in red, and underlined, its me using all caps to make the point.)
2) Alternate between short bursts of hard acceleration and braking, not cruising or sitting in traffic but varying speed for the first 200 miles or so.

Braking by the way simply means closing the throttle, not using the brakes.

And that's about it. The rest is how to do it on a track, or dyno, to be careful, not exceed speed limits, etc. All the rest is devoted to critically examining the many other ideas that are out there.

Part Two http://www.mototuneusa.com/power_new...horsepower.htm talks about the importance of thinking outside the box and critically examining ideas, and includes comments from a number of readers who followed (or didn't) the above procedures, and the horsepower they did (or didn't) gain.

Part Three http://www.mototuneusa.com/power_new..._superbike.htm talks about how cognitive dissonance can prevent you from learning new things, a review of squish area, and again the importance of ring seal in achieving both power and reliability.

Part Four http://www.mototuneusa.com/power_new..._for_speed.htm scroll way down to where he talks about ceramic, nikasil, etc cylinders.

And finally, Part Five http://www.mototuneusa.com/power_new...ular_logic.htm
Do ball bearings require break-in? How do plain bearings work? How do they fit, and stay in place? What is bearing crush? The power of hydraulics! Babbit, copper and steel- the ingenious design of plain bearings. Main bearings and oil circulation through an engine. Do yourself a big, big favor and find the time to read all the way through this one!

Seriously. Bookmark it. Come back to it. Study and think hard on it.

Whew!

And now, after all this, sorry to have to tell you this but in all probability it is just not all that big a deal. I mean, really. Think about it. Apply all the same COTBT as above. Even if the Motoman is right (and he is, but never mind) but even if he is then what's he really saying? Greater long-term reliability and 2-10% more horsepower. Sure 10% on an S is 40 hp, more than you get with X51 for $18k. But realistically? Probably a barely noticeable 10-20hp. And long-term? Well long-term covers a lot of ground, but still, unless you're tracking a lot year after year or not following recommended maintenance schedules its highly likely you'll run 150k or more miles without anything but scheduled maintenance anyway. For most people that equates to at least ten, up to maybe twenty years of driving. It just seems to me that, regardless of what you do during the first 20-4000 miles, nothing short of outright abuse is going to prevent your 991 from delivering tons of incredibly high-performance driving satisfaction for many years to come.

So its not like I spend a lot of time worrying about that. A bigger concern for me has to do with things like missed opportunities, of not quite taking advantage of everything Porsche has gone to such pains to provide for us. Thankfully, there is no reason not to, and the moment my new car is completely warmed up I look forward to seeing what it can do. Stuttgart is in the middle of town, so this is probably going to mean Leipzig delivery and straight onto the track.

One last little bit. In spite of what you may be feeling right now there really are a great bunch of guys here, with an invaluable knowledge base and- occasional ribbing aside- a genuine desire to help by sharing. Seriously. Group hug.

jmct

Chuck911: I noticed you replied to 911dreamer. Not sure if you missed my post directed to you making a specific counterpoint as you requested in your post.

Appreciate if you would reply to it, especially considering you asked for specific counterpoint(s) and have now received them.

Thanks

991Dreamer

xx

991Dreamer

Thanks Chuck. I really didn’t mean to stir the pot; was only trying to get a handle on how I should drive this car for the first few hundred/couple of thousand miles.

The above may be verisimilar, but jmct’s post makes sense, at least to this mechanically challenged simpleton.

This is me exactly (except the getting it right regardless of effort part)! I will probably keep this car for 10+ years. That being said, am I getting in a twist unnecessarily due to the fact I drive 3-4k miles a year?

Again, I appreciate the time and effort you put in to your reply but I’m just too lazy to do this. Like my home life I really just want to be told what to do. Maybe all of you could just consider yourselves my Rennlist wives.

Never doubted that for one second. I am so appreciative of the time people take to try to educate/help those like me.

Would love to read a reply to jmct’s above post!

chuck911

My post a few days back was written at work while killing time waiting for my OR case to start. Next thing you know, massive OT, Christmas.... couple days went by, and scanning quickly coming back to it must have missed this. Sorry bout that. I think this must be what you're talking about:

1.
Last year I had the pleasure of meeting Andreas Preuninger, head of GT car development at Porsche. This was at the 997 RS 4.0 litre preview in the UK.
A few of us asked about running in. He said the following:
- For the first couple of hundred miles drive the car gently; no high revs and don't let the engine labour. The main thing here is bedding in tyres and brakes.
- Up to around 500 miles, vary engine load and speed. Use perhaps 2/3rd of the rev range (when warm of course). No full throttle.
- Between 500 and 1,000 miles start to use more of the revs, and larger (occasional full) throttle openings. (I tend to up my rev limit 1,000 rpm per 100 miles.)
- Beyond 1,000 miles drive the car as you wish.
He confirmed that most GT engines develop their full potential around 10,000 miles - most 3.8 RS engines were over 460hp (10 up on OEM figures) at this mileage.
I've pretty much used AP's technique for years now - most notably on a 996 GT3 Gen 2 that has now done 60,000 miles, half on track. The engine uses no oil, and still develops 430 hp (it has a Manthey map and exhaust).

The point to make is that this is what we call an appeal to authority. But if the idea has merit then who cares whose idea it is? Imagine your next door neighbor, or maybe the service manager at Ford, said the exact same thing. Would you give it any more or less credibility?

The entire point of what we might call The Motoman Hypothesis is that modern manufacturing techniques have long since reached the point where the only engine components requiring break-in are piston rings, and that only repeated bursts of full-throttle loading done while the cylinders still show honing marks is capable of fully seating the rings. The honed cylinder wall surface acts like micro files that can finish seating the rings, but this requires the high pressures of full throttle. If driven gently the rings will still wear down and polish the cylinder walls, but without the high pressures needed to press them hard against the wall will never seat properly. The window for this is roughly 20-200 miles.

Consequently, since your neighbor is saying drive gently the first 500 miles, well past the point of ever possibly being able to seat the rings, nothing he says after that matters at all. That is, it has zero impact on The Motoman Hypothesis.

That said, we can still think about the validity of your neighbors story.

Even tires and brakes need nowhere near 500 miles to be "bedded in", whatever that means in terms of tires anyway. Significantly, there are no reasons given for any of these steps. Evidently we are just supposed to believe this guy. Well he is your neighbor, after all! Would really love to hear the engineering reasons behind the need to increase RPM limits by 10 RPM's per mile. A far simpler and more likely explanation is he's merely repeating the corporate CYA line.

2.
When we do our engine test, the metals inside the engine never reach the temperatures they would when driven on the street since the test session is fairly short. In other words, the bearings, pistons and cylinders never get a chance to thermally expand to their maximum. Therefore, there is little wear on the moving components. But when you drive a car on the street, the engine parts expand considerably more because of the heat being generated from the engine running for an extended period of time. No matter how tight the tolerances are, there is always a slight amount of expansion in the material. The moving parts can wear quickly if exposed to excessive heat and not always in a uniform way. We also constantly vary the speed and allow the engine to run at both high and low RPM’s”.
“Porsche wants the engine to break-in slowly, which means it needs to maintain a lower operating temperature (below 4,000 RPM) and to allow all parts to adjust (wear-in) within their own thermal expansion parameters. This is also the reason why Porsche wants the owner to vary the RPM throughout the break-in period; therefore the engine doesn’t get use to one operating temperature range”.
“Porsche has been using Mobil 1 Oil since the early 90’s. With its superior lubricating properties, it takes many miles of driving (without getting the engine too hot) before the components actually seat (or break-in). Porsche’s own tests reveal that after 2,000 miles have been driven, all of the moving parts have had a chance to wear into their adjacent surfaces and then an increase in engine RPM is permissible.”

Lotta crazy stuff going on here. Not sure why the misdirection regarding test temperatures. Not sure what he is saying at all. Total confusion. No trouble at all to go on YouTube and watch video after video of Porsche extensively testing engines under ever conceivable operating environment, yet if you read whats above it sounds like they never even let engines warm up completely. The statement seems calibrated to make you afraid even of driving the car more than a few minutes at a time. Which of course is baloney.

Ditto the comments about "components actually seat (or break-in)" and "all of the moving parts have had a chance to wear into their adjacent surfaces". This simply never happens!

Engine parts such as main and rod bearings ride on a film of oil such that adjacent surfaces NEVER EVEN TOUCH. If ANY actual metal to metal contact were to occur then one part would deposit material on the other, destroying precision tolerances, leading rather quickly to still more galling, heat build-up and engine failure. Follow the link to Motoman Part 5 for lots of photos of bearings, micrometer readings, and animations demonstrating these basic facts.

speed21

...or leaning on the end of a crack pipe or bong.

Sheesh. You surely can't be serious. The whole site is merely a mixture of extracts from various component manufacturers combined with a very childishly articulated litany of emotive submissions based around his rebuilding of 300 motor bike engines, over what evidently appears to be a very brief carreer (based upon his age,.. re photo of himself).

Needless to say the rebuilding of 300 motor bike engines wouldn't even represent a drop in the bucket in comparison to Porsche and many other mass engine manufacturers who engage a vast range of testing and evaluation procedures to arrive at what is the best way for the purchaser to use the product in the initial stages.

I could only imagine what his facility represents in comparison to Porsches R and D department....least of all the expertise employed. Laughable.

This person appears to be just another grease monkey trying to have everyone believe he is some form of brain surgeon. I note he says he worked at Nissan at one stage but he didn't allude to the actual position he held there (LOL i wonder why?). When you look at the time and effort he's gone to in constructing this wacky site you'd have to seriously question why would you do that. He could possibly have been a disgruntled menial subordinate, fired by an educated engineer, now with an axe to grind against his previous superiors/ employer? And if he isn't, he sure comes across that way. That would at least (possibly) explain all of the childish emotionally charged ranting.

In summary there is nothing of any brilliance, least of all worthy wasting time reading beyond a quick skim.

And for anyone to stereotype every solitary engine on the planet as being the same in terms of how it should be used or "broken in" needs their own head checked....and fast.

jmct

Chuck911: Thanks for replying and no problem about the delay, but there is some confusion. The post I was referring to was later - let me just paste a copy of it below to avoid further confusion. I'm sorry you went through the hassle of replying to the other one but if you would make a few minutes time, I would still really appreciate you answering this one - thanks:

Hello chuck911: In a post a few minutes ago in this thread, I commented on why I discount mototuneusa.com's evidence on break-in. Essentially, the combustion cycles of 2- and 4-cycle are substantially different and so while his advice may be good for a 2-cycle, it is a leap to suggest it is universal. The Wikipedia links show a good illustration of the differences as a point of reference.

http://en.wikipedia.org/wiki/Two-stroke_engine
http://en.wikipedia.org/wiki/Four-stroke_engine

I did not see much from mototuneusa.com to support his assertion that his results should be viewed universally - would you mind commenting on why you feel so strongly about its applicability to 911 break-in?

chuck911

Right. Well a couple things about that.

First off, thanks for bringing up something pertinent. Its a welcome relief from all the personal attacks and appeals to authority. Greatly appreciated.

I did look at the photos and it took me a bit but the pistons in the collection, some are obviously 2-stroke, some 4-stroke... one or two I'm not sure what they are! But, I really don't see that it matters.

Set aside the fact that Motoman himself does recommend his 'warm-up followed by repeated full-throttle accelerations the first 20 miles' method for 2-strokes (snowmobiles) as well as 4-strokes. What's the reason to think otherwise?

The hypothesis or rationale he's offering is that only high pressures from full throttle are capable of fully seating piston rings, and even then only during the first 20-200 miles, before the new cylinder honing roughness has been worn smooth. What is there about 2-strokes that would change any of this?

You are absolutely right in saying he gives zero evidence supporting his contention that this break-in technique is applicable to snowmobiles, lawnmowers, etc. But there's also no evidence that it works on Moto-Guzzi, Porsche or BMW. There is only an abundance of evidence that it works on engines with cylinders, and piston rings designed to channel combustion pressure so that it presses the rings against the cylinder wall. Since this design encompasses all modern 2- and 4-stroke engines, what more do we need to know?

jmct

Thank you for the comments, I read them carefully. A few questions:

1. I want to make sure I understand you, is it fair to say that your view (taken alongside your comments) is that a piston is a piston, a piston-ring is a piston-ring and a cylinder is a cylinder, so therefore it is reasonable to expect 2-cycle combustion effects on those parts (or 4-cycle effects from generally any engine) to be a good predictor of what will happen in a Porsche 911 engine?

2. Further, that the prediction is so accurate (despite any number of subtle differences in the specifications of those parts including design details, materials used and size) that it makes sense to advise against a graduated break-in where redline is prescribed after several hundred miles and instead advise redlining the car immediately after its first warm-up? Putting the question another way, it is not possible in your view for subtle differences in parts design and redline-level to have even a moderate impact on break-in procedures?

3. You mentioned that other engine parts (e.g., crank case bearings) benefit from oil coatings, so they don't touch. It is generally observed and agreed that a new engine is very "tight" meaning that there is little tolerance throughout the various bearings and this changes especially during the first few hundred miles and certainly over the first thousand. If you agree, how is this possible given your comments about oil? (I believe you assert that these parts do not need any break-in whatsoever). Or putting the question another way, you believe there should be no change in the tightness of these parts from when the engine is new to when it has been used for a few hundred miles of driving?

Will greatly appreciate if you can reply. I have some comments but want to ensure I understand your view first. Please let me know if you have any questions for me - I do have the two questions from your previous reply noted.

chuck911

Okay. Well first off its not my view, nor my idea. There's a problem percolating just below the surface here that has to do with something I have mentioned before, a logic flaw called the appeal to authority. That's not mine either, just something useful that's been around a very long time. The point is to keep the focus on the idea and not the person. Ideas are impersonal things. The reason I keep mentioning Motoman is not to appeal to him as an authority (which in any case would have the opposite effect, the consensus seeming to be he's just some bong-hitting video gamer) and anyway its not really his idea. Its been around a long time already. I mention him for attribution, as a way of giving him credit for taking time to publish and explain something valuable that can really help people.

As for it not being his idea... haven't mentioned this before because it falls into the ATA category, but when I rebuilt my 240-Z motor back in 1977 the short block came back with break-in instructions that were remarkably similar to Motomans. As best I'm able to recall they were
1) idle until fully warmed up
2) accelerate all the way through first gear then lift off the gas and let the motor brake the car, repeat several times
3) repeat above in 2nd
4) repeat in 3rd
5) drive with varying load and RPM
6) change oil at 20 miles
That's exactly what I did. No problems. Buddy of mine, same summer, rebuilt his Ford Pinto. Machinist at the shop did fantastic work- balanced, matched pistons- and told him pretty much the same thing. More recently, best Porsche mechanic I know gave me the same advice after rebuilding my 911SC. We talked about this recently and he agreed, most important thing is to seat the rings.

So its not like this is anything new. In fact, in my opinion, what is new is the legalization of every facet of society to the point manufacturers who know better are giving customers advice they know will stand up in court even though they know full well never to use it where it really counts, on the race track. How people are able to make fun of the manual telling owners not to reach through the steering wheel while driving, yet refuse to admit even the possibility that break-in instructions are equally lawyer-driven is beyond me. Okay. Enough soap-box.

1. Sure seems that way.

2. The first part is a mischaracterization. Everyone wants to conflate full throttle with abuse, but there's nowhere Motoman says to redline asap. In fact, he never says to redline at all. The whole focus is on generating sufficient power to push the rings into the cylinder wall forcefully enough to fully seat against the cylinder. That means full throttle, but not necessarily to redline.

That said, what reason would there be to expect damage from redline at say 50 miles but not at 500 or 5000? When answering, please do try to keep in mind that many manufacturers- including Porsche- run newly assembled engines right to redline at zero miles. No fair dodging with they only do this to a small sample. That small sample still gets sold. So why aren't they ruined?

Last part of your question- short answer: no.

3. This was certainly true long ago, and may even have been true as recently as the 1970's, but in no way has it been the case for the last several decades, at least. Main and rod bearings simply do not bed in, period. In fact, they do not even wear! Well, there is ONE TIME when they do wear, but I want people to think about it rather than me telling everything.

Correct, these parts do not break in. In fact what is not only "generally known and agreed" but is the foundation stone upon which engines run is that the metal parts ride on a hydraulic film of oil so that the metals themselves never touch. This is why oil viscosity, temperature and pressure is such a big deal. If the things people talk about (aka "bedding in") ever really did happen it would be hours, if not minutes, from total engine failure.

"No change in tightness", in a world where we can measure nanometers and angstroms (view atoms, etc), "no" is a pretty tall order. Scroll down a ways on this page for everything you're asking and more http://www.mototuneusa.com/power_new...ular_logic.htm

If I get your drift, the answer I think is yes parts do wear over time. (Most of that wear occurs not when most people think, but have you thought yet about when it does happen???) But that is a reason to expect brand new motors to be more, not less, able to sustain full load and RPM than older ones. Indeed, does ANY motor race team from F1 on down put 500- let alone 5000!- easy miles on before declaring the motor race-ready?

Mike in CA

I don't mean to be unfair by focusing on this one aspect of your argument, but I think it does warrant comment. F1 teams, to use your example, are allowed 8 engines in a season without penalty and each engine, given an average race distance of appoximately 200 miles, and including practice and qualifying, is expected to last under 1K miles. Most road car owners expect their engines will last at least 100K miles and that they will never have to replace an engine as long as they own their car. Given that, I don't think comparing street and race engines is particularly useful.

IMO, the issue with proper break-in relates not so much to whether the engine makes good power early in it's service life, but whether it does so long term with minimal problems. Without meaningful extended data on the performance , durability, and wear over time for many engine samples, (things that Motoman, for example, does not provide or even reference) it's very difficult to validate the benefits of "hard" break-in, other than with individual anecdotal evidence such as "I've done it, had my engine for xxxxx miles, and had no problems".

Now, I haven't seen actual data from Porsche either, but they have been building, warrantying, and servicing flat six engines for over 50 years and have vast experience with them. So, for the engine in my $100K+ pride and joy, should I follow the unsubstantiated "Motoman Internet Hypothesis", or the unsubstantiated (to me at least) recommendation of the manufacturer? For me, the choice is logical and fairly easy.

simsgw

Swore I was going to keep out of this thread, but I have to make a couple of quick comments because this is lovely example of why we do appeal to authority in matters of physical science. I understand your using this as an objection Chuck, but it isn't a fallacy in science. It is the way we build new generations of knowledge on the work of the past. Science is bloody hard and we expend long hours, no... Long years to open new areas of science. Someone willing to do those years of work to investigate new data in an area well explored in the past, can add to an existing authority, or even supplant them completely in the new areas. And in the process of being reviewed by peers worldwide that person becomes an authority as well. (Or a laughing stock in cases of error. Life is cruel.)

So if some yobbo doesn't believe a satellite will stay in orbit, if he says "that's silly. What goes up must come down." It is perfectly acceptable to refer him to Kepler and send him away so I can get back to work on real problems. And Kepler makes a good example because he is an authority and more modern authorities know when his work is insufficiently detailed to solve modern problems. Which areas he could not address in one lifetime. For example, the orbital decay we observe, or the orbital fluctuations that turned out to be revealing deep structures of the Earth that make the Keplerian premises imprecise. If one of my grad students complained that "the data must be wrong, satellites can't do that" I would refer her not to Kepler in this case but to any of several modern authorities on near-earth orbit dynamics. Note that I would not sit down and reconstruct Kepler's work and then modify that to incorporate modern data. Several scientific lifetimes already were expended to that end. I would send her off to read a paper or a book summarizing the work. If she insisted the data still had discrepancies with that modern explanation, then I'd suggest a few months work to see if she had a possible thesis topic. A few months of work.

We would get nothing done if we did not accept the authority of past work, subject only to seeing discrepancies that rouse our scientific hunger for new findings. We are eager to find discrepancies, but we don't run around proving Kepler again for laymen who can't believe satellites stay up while apples fall down.

Now Chuck's question:
"Gary said there is higher wear at 50 miles." is a perfectly valid answer. Unless 'gary' is some wacko with a motorcycle shop in Fargo. If Gary is the nearest graduate engineer, and no one offers a contradictory assertion by another nearby engineer, then you're done. Because you don't want to go reconstructing Kepler's work or Gary's. Absent discrepant data and someone qualified to appraise them, you have a rational basis for proceeding: "More risk of damage at low miles." Completely rational.

This case is simple enough to explain I suppose, but I'm off to watch a movie and make it through to midnight. 'Simple' still would require a half hour of typing and I'm still not a fan of this thread. Maybe one of the other engineers can spare the time.

You're asserting facts not in evidence. Manufacturers of every product from chips to chocolate cookies do this. Items are pulled at random off the line for testing. Objectives in quality control determine how many per 1000 are required to establish the necessary assurance that the line is working correctly. Whether the sampled items go back into inventory depends on the tests that are run. You've asked "why aren't they ruined?" Some of them will be. I'm not a mechanical engineer and even one such would defer to a specialist in engine manufacturing, so I can't even guess how many will be ruined by testing. But it won't be zero. The whole point is to detect problems with the manufacturing line. I never have asked, but I would fully expect that after running up the engine, they don't holler: "Ja! She runs! Let's go get schnitzel!" I speak subject to correction of course.

Instead the engine will be operated in a precise sequence, with instrumentation to determine performance, fuel consumption, and exhaust character. Then some fraction of the sampled engines will be disassembled for examination of components more closely. If the sample frequency is high enough to be expensive, another fraction will be put back into the line, but again, don't assume no further work will be done. Given the computer-controlled sequence of operations, they will know which components need replacement, which just need industrial cleaning, and which can be ignored. Surely its obvious that a heavy-foot customer and a computer controlled testbed are markedly different in the predictability of the loads they impose. I know none of those things remember. Not about Porsche's factory. As I said, I'm not an automotive manufacturing engineer. I just know that's how we do it in manufacturing for other fields, so it's a safe bet Porsche does something similar.

Now the engines they put back on the line may go into customer cars or, depending on past experience, they may not be comfortable doing that. They may put them only into cars destined for "Executive" use, which is to say the press fleet and similar roles. Or into internal training programs. In space work, we put such test platforms into grunt work duty. Destructive testing of subsystems, training programs, that sort of thing.

Don't consider "appeal to authority" an excuse to ignore what you are told about physical science. Politics certainly. Social science definitely. Physical science no. Authority is all you ever will have except in the limited fields you may pursue personally. And don't presume you know what Porsche does in their factories unless a Porsche engineering manager tells you. An authority, in other words.

Gary

jmct

Thanks for answering in such detail. I appreciated hearing how you thought about it and wanted the opportunity to be able to consider the details.

I am lucky and thankful to Mike in CA and Gary for replying before me because I intended to reply with essentially their comments - my view and counterpoints are very much in-line with theirs.

I agree that experience counts and the appeal to authority is to be applied exactly as Gary describes, in my opinion. I think there is a lot of speculation we are all forced to make about 911 engine break-in and so I give significant weight to the GT engineer over mototuneusa.com, but equally as importantly, the Porsche advice is much more consistent with my personal engine experience.

I definitely disagree with your view that break-ins can be generalized across engines to the extent you are doing so. Let me give you an example. I spoke to a good friend for a while about this a couple of days ago, someone who has a lot of propeller-airplane engine rebuilding experience, who owns his 3rd 911 and importantly, is a good thinker. He agreed with the Porsche recommendations I earlier quoted, baby it for a couple hundred miles, be very careful of excessive heat generation, etc. But when I asked him how he breaks in airplane rebuilds he said warm it up and redline it for 2 hours straight, because redline is only 2,700 RPMs so it's easy to break in the cylinder walls without hurting other engine parts. My point is, differences in engine design and configuration matter and thinking one person's comments on a website about motorcycle results can be universal is at a minimum, risky. I think you're a doctor? Think of the critical differences in applying medicine to only subtle variations in situations.

Respectfully, I think driving a 911 hard after it's first warm-up is a terrible idea and I would like you to reconsider doing that with your first 911 and take the more conservative route (considering our lack of 911 data) and follow the Porsche advice. You have all the evidence you need to disagree but you are spending a lot of time and effort for a car you obviously admire very much and I would like to see you get the most from it. I'll tell you what I've loved the most about my 911's, for whatever reasons, it's redline in second gear. I love the thrill of it and it's something I can actually enjoy (occasionally) street driving, and I want you to find your own favorite experiences while getting the absolute most out of your 911.