I should have my MCS in a few days and I am wondering about the best way to break in the Mini. Not what dealer or factory says, but what you guys think. I ride motocross and with the high performance bikes the best way to break them in is to break them in hard. I truly believe this guys theory but it applies to motorcycles. Do you think this would apply to the Mini's?

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

 

I agree with what you are saying and with the proceedure in article, which I have seen before. I think that manufacturers for cars and bikes are giving out the same breakin information that they have been giving for the last 50 years. It may have made sense 50 years ago when tolerances were sloppy, but not today. I have broken in sport motorcycles and noticed the difference in power after about 25 miles. I take them up and down through the revs and the gears for a few heat cycles. No steady speed, but also no sustained full power or sustained high revs. Change the oil to get the junk out and good to go. I think that running an engine at low power and low revs on the freeway for hundreds of miles before changing the oil has to be about the worst thing.

 

Well, this is quite an intersting thread and I would like to hear the results as well. I, not having much experience in this area, do however have a few problems with "MotoMan"'s interpretation of what is going on in the engine. My first issue is with, "If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ... How can such a small amount of spring tension seal against thousands of PSI...of combustion pressure?...Of course it can't." Well, while my knowledge of intricate engine mechanics is very small I do know a bit of physics and I can tell you right now that the spring tension has nothing to do with how well it can hold against PSI. In this case the spring tension is place horizontally against the cylinder wall, and the PSI of the combustion is pushing vertically downward in the cylinder. The two forces really have little effect on each other because they operate perpendicularly. If I were to guess the PSI is held in by oil pressure and the ring cuts in the cylinder heads that hold the seals there. The seals I imagine just act in a way that the cylinder head does not have to rub against the cylinder walls to seal itself. The only way that the tension of the spring could be used in the manner that he described would be if the force of friction between the seal and the cylinder wall sealed in the gasses...and that doesn't make much sense because friction is a bad thing in an engine.

The next part I have a problem with is, "Because, when the rings don't seal well, the blow-by gasses contaminate the oil with acids and other harmful combustion by-products!" Now anyone with basic chemistry knowledge would just laugh at this because we know that in any combustion there are only two products, CO2 and H2O...Carbon Dioxide and Water (vapor probably). Acid just is not possible from this reaction. If you get acid in your engine it is not from the combusion or the combustion gasses.

Now I may be wrong in how the engine actually operates, but the tension and the acids subjects I am quite sure about since it is pretty basic physics and chemistry. But the truth about what a break in should be is quite interesting and I would like to hear form a source that really knows what is going on and how it should be done.

 

Ok, before I get flamed I would like to point out something. I am not saying he is wrong or that his methods are wrong. All I'm saying is that his arguements are not adding up. For my PSI arguement, he might be right in what he says (I really don't know), but he is arguing against the ring seal idea. To simplify what I'm saying is that he is like a mathematician in a deep arguement about advanced math and is arguing he is right because 1+1 does not equal 3. Well DUH! His arguement on the PSI issue is simply wrong, but his answer may in fact be right. Ugh, I'm sorry for wasting space, I just don't like getting flamed for a miscommunication.

 

I motor on the highway every day. During my break in I would make sure I was always changing the revs by changing gears.I mostly keep to the 4500 rpm limit that MINI said to do, but I did do brief runs up to 6500rpm.

No hard launches, tried to not keep a constant rev. on the tach.

Break in took me a week, that was 2 years and 52K miles ago. My MINI is running like a top.

First thing I did after break in, find out what bounce was all about

 

Interesting, we just picked up a new Jeep Wrangler for my wife. I checked the manual and it said something about keeping below redline and the usual do not drive at a constant spped but said that occasional full throttle starts are actually good for the engine. I'll try to check the actual text of teh manual later.

 

You also need to remember that you are breaking in the engine with synthetic oil and most people tend to agree that this is a longer process. I think this is why BMWs have a pretty long brake-in procedure. To say that car manufacturers do this because they have been doing it for the last 50 years is probably a false assumption. I am sure the recommendations come from the engineers and they are pretty smart people.

 

Generally, car manufacturers set break-in procedures based on trial and error. Wonder why the MINI's break-in is 1250 miles, whereas a Honda may only be 200-300 miles? Is this arbitrary?
Probably not. Most likely, they start with a figure. Test it on cars and break them apart for inspection. If wear isn't acceptable, they increase the duration.

The MINI has tighter tolerances than cars built 50 years ago, but has also introduced some components not around back then.
The MINI has a piston featuring a very thin coating of grafal on the skirt. The pistons are of aluminum construction with a grafal coating applied to the skirt to reduce noise, friction, and scuffing. Grafal consists of a fine colloidal graphite which is bonded with resin. It is between 10 and 20 micrometers thick (0.010-0.020 mm) and is applied by means of a printing process, followed by curing. Improved adhesion properties are achieved by a thin metallic phospate layer or other proven methods which are applied prior to coating.

Most notably are the coated vanes on the supercharger--this is the biggest reason not to rev above 4500rpm or full throttle during break-in. These faces of the vanes are not lubricated by oil or anything else for that matter.

I believe the 1250 mile break-in period recommended by BMW is established largely because of the supercharger, since you have to go through the break-in period again if you later install the JCW kit (since it replaces the supercharger).

I don't think the piston ring seating by itself requires more than a few hundred miles.

 

The guy says don't use synthetic oil for the breakin. Kind of hard to do with our minis, since they come with synthetic oil. I had always heard that synthetic oil was bad for a new engine, but mini must think differently to be using it. Also, they may be doing some breakin at the factory. I was told by the mini salesman that the engines are shipped from brazil with a special breakin oil that is changed to synthetic at the mini factory in England. That's why you don't need to do the first oil change until $10K miles.

I am going to pick up my new mini from a dealer 2.5 hours away from my house. I need to get the car home on the freeway. I think everyone is in agreement that the breakin requires going at different speeds, and using different gearing often, so I should not use cruise control and should run through the gears often. Am I right that the only issue is whether to push the engine to redline or keep the rpms lower per mini's instructions? Anyone have thoughts on that?

Also, in the old days they said to break in an engine at speeds below 40 mph. Now they say just keep it under, I believe, 70 mph. I don't see why mph is relevant at all, since I assume the engine doesn't know how fast the car is going. All the engine knows is RPM, right? If you're at 6,000 rpm (to make up a number), does it matter to the engine whether you're going 5 mph in first gear or 100 mph in 6th gear? If I'm right, shifting between 3rd and 6th on the freeway should accomplish a lot of the goals (and maybe get off the freeway once in a while to let the rpms get real low).?

 

Deuce,
I hate to disagree, but acid buildup in the engine is a serious concern. Sulfuric acid only requires sulfur, water, and oxygen (H2SO4). Sulfur is present in fuel, and water and oxygen are readily available in the combustion chamber and oil pan. Hydrochloric acid is also possible (chlorine is in the fuel also) (HCl). Another possibility is Carbonic acid (H2CO3) wich only needs hydrogen, carbon, and oxygen. This is why it is critical that the oil be changed before the additive package that neutralizes these acids is used up. We could debate all day the point at which these additives will be gone, but the oil change intervals recommended by MINI are their "best guess" at a reasonable interval with "normal driving".

For my money, the engineers that designed the engine have come up with a reasonable break-in period. Until I have learned more about engineering than they have, I will try to follow their recommendations. Remember that most manufacturers consider the "life" of a car at 100,000 miles. If you wish to get more life from a car than that you may need to exceed their recomendations. In other words, err on the side of caution.

 

I think we don't even need to get all techy about this issue. Let's simplify things here. Yes, a MINI's break-in period seems quite long, and it is therefore hard to obey the suggestions of your dealer, but me personally, I'd much rather err on the side of caution, and follow those suggestions, rather than cause premature wear on the engine. Wear that might not rear its' ugly head until 70k miles, or 100k miles, but could also show up at 25k miles... who knows?

Sure, keeping the engine under 4,500 RPM's is hard, when all you want to do is drive your MINI like you just stole it. Yes, no full-throttle launches, and yes, you should not keep the engine at one RPM for long (i.e., modulate your RPM's often). But what could it hurt, to follow these suggestions? Better safe, than sorry.

Your engine will be better off if you follow these suggestions. That is a fact. Whether you choose to obey is your choice. So be patient, new MINI owners, your day to mash the pedal to the floor will arrive sooner than you think.

 

MINI/BMW Engineers are clueless, I'd follow the Motorcycle Dude's break-in procedure!

 

Well after a bit of research I suppose that Sulfur could be present, but only if the fuel you are getting is quite impure. Sulfur is deliberately removed because of it's corrosive nature to engines, but since it is found naturally with gasoline I will concede that it is possible to remain there. In the end I'm not say that acid can't exist in an engine, what I'm saying is that it can't(or rather shouldn't) come from the combustion process as he dictates since gasoline is a hydrocarbon (only carbons and Hydrogens and possibly a few Oxygens depending on the additives) and Oxygen. As far as carbonic acid goes, I find that a little bit harder to stomach. Though the peices are there to create it as it is highly unstable (it really really wants to be CO2) and is only present when Carbon Dioxide is dissolved in water. So I concede that acid may exist in an engine, but only through impure gasoline or some other source of the engine(which I was not debating) and Carbonic Acid is highly unlikely.

 

I just followed instructions. Wasn't that hard.:smile:

 

OK, here is the language from my 2005 Jeep Wrangler owners manual. (which is of course a naturally aspirated, standard oil lubed I-6 that develops something like 60% of its peak tourque at idle and redlines at 5500 RPM)


Actually the more I read it the less clear it becomes.

 

don't think too much. just take it easy. :smile:

 

drive like you mean it, keep in mind, if anything is gonna happen, it will happen sooner or later, has nothing to do with break-in, everything is under warranty anyways, don't worry about it, just enjoy it

 

There are trace amounts (~10 to 20 ppm) of sulfur in all gasoline, in diesel engines, sulfur is responsible for particulate emissions and there is a move afoot to get sulfur in diesel fuel down to ~5 ppm in the U.S. You can also identify the sulfur content if you follow certain manufacturers (for some reason, it seems that most of the offending manufacturers are located in Asia) cars up a hill - there will be a slight rotten egg odor (H2S).... Net, net, there is a small exposure to sullfuric acid contamination of the oil (which is why motor oil manufacturers blend an additive package with the oil).

This is starting to split hairs; there is a trace amount of sulfur in the fuel mix. When the fuel mix is combusted, the sulfur gets burned along with the rest of what is in the fuel mix.

Don't know about carbonic acid. I doubt that the additive package that is blended into the oil by the manufacturer is selective about what it neutralizes (sulfuris vs carbonic). Rather, the additive package is focused more on ph level - analogous to how sodium bicarbonate works.

 

What happens when the warranty coverage has expired (and a part that was abused during break-in decides to go on holiday at say, 60,000 miles)? I tend to follow a process that stays within the factory recommendations: No lugging of the engine; for the first 600 miles (on the MINI) I kept the revs below 3,500 so the rings could seat; and vary the engine loading (no constant engine speed and I have some nice hills to go up and down). I also replace the oil and filter at the 1,250 mile mark. If you doubt that metal particles are being thrown off during break-in, send a sample of your oil off for analysis - you will be surprised at the results.... I will also change the oil and filter once again at around 5,000 miles (to again get rid of the metal particles that are thrown off as the engine continues to wear in). Following this procedure has given me some very long-lived (~200,000 miles before oil consumption gets excessive) engines in the past.

 

The MCS supercharger has an abraidable coating on the vanes and case to improve tolerances. It's my understanding that excessive rpm's durring the break-in period may cause improper bedding of the supercharger vanes. This would lead not to failure but reduced performance. My goal is to not only have a trouble free MINI but one that also performs as designed.

 

Based on all the information it seems that the best is to just follow the book. Thanks for all the replies. I guess the break in is a lot different than motorcycles especially since there is a supercharger that needs breaking in as well. Thanks.

 

I've read all of these posts before posting, and the one I'm quoting has the most impact. First off , ring seal Has little to do w/ the spring tension of the rings. The spring tension is only needed when cranking. After the engine fires, compression pressures and cumbustion pressures take over. The two top rings in any conventional internal combustion engine, are designed and manufactured w/ a beveled inside edge , that is installed toward the top of the pistons. Therefore the outward forces against the cylinder wall(ring seal )are created not by spring tension, but by the outward forces created against this beveled edge, by compression and combustion pressures, forcing them outwards against the cylinder walls.
All this talk and theorizing is great, but some of you would do well to just take an on line course in auto mechanics. Get down the basics, First.
Oh and break it in like you want it to run!!!@WOT

 

As for Oil pressure, There is none in the cylinder. The oil travels from the block to the crank main journels, through drilled passages to the rod journels, spills out onto the rod beams, runs up to the piston pins and returns to the pan. The oil that lubricates the pistons and cylinders, actually gets splashed up on the piston skirts, by the crankshaft and rods as they rotate through the oil in the oil pan . The MCS pistons get additional help as they are squirted w/ oil to help in cooling. Each piston has the two top rings that form the "seal" and a third set of oil scrapers that keep two much oil from reaching the cumbustion chamber where it would be burned.Break it in the way you want it to run!!WOT!!

 

I broke in my last motorcyle in by riding hard and the same went with my Audi S4. Needless to say the Audi put out consistantly more HP on the Dyno than any other like car. I never had any problems with either of them.. I figure drive it like you stole it

 

Ring seal is what is being debated here, and it can't happend at low RPMs thus this debate. I dont want to have an engine that runs for 200k miles if it is only opperating at 80% of its potential, any more than I would want to have a paint job that lasted for ever, if it didnt look near as good as one that only lasted 10-15 yrs.