Originally Posted by crabman

Mixed bag on break in, I say that as someone who had access to a very large database with logged engine, transmission, reduction gear, PTO, and other similar equipment, lots of data over the lifetime of these components. More interesting is that in the commercial space you are sometimes talking about multiple lifetimes; you have sleeved bores and all that, they're designed to be renewed endlessly. This means you can see the same engine operated under different parameters. It's commercial usage, but in broad strokes, I'd say it's pertinent.

With cars you've got a lot of different components with differing needs for directed break-in operation. In my opinion, based on what I know, you don't need to worry about the engine, it left the factory with enough revolutions to be largely beyond any benefit, and moderate initial loading may show an extended service life.

Probably time to be talking about moderate, and with it, duration. Should you enter into a commercial endeavor involving an engine that costs you millions; you have incentive to get it right. What right will end up looking like is a load table defining the load you're going to put on the engine over the time following the first start. You'll be hooking up to a load cell for smaller engines; these are usually nothing more than a great big toaster, tons of toaster, and the resistance is going to be your load. Bigger engines in power plants may be aligned into an array and load sharing will be used to control the load. On a boat, with main propulsion, they will pull on the dock to start, and then head out to a sea after a short time, where they will introduce load as directed during a sea trial. There is always a way, and when it's your millions, you're going to follow the procedure. This is almost invariably going to be a light load that is increased over time.

So then you've got duration; how long will this directed operation go on? This will usually be defined in hours, and it's not many, as little as a few, to around 20 for some gears, the longest I'm aware of are ring and pinions. There could be others that are more, can't say.

To go back to that engine, it has been started and stopped multiple times before you got the car. This isn't just a matter of making revolutions, its had heat cycles, that's a good thing. When it's my money, I don't baby it, but I do drive moderately in the early miles. I vary my speeds. If at all possible, I'd arrange for heat cycles in those early miles.

So why the heat cycles? That would be your diff, those gears require a mating process to reach their final service condition and that can only happen during actual use. Overloading these gears before they are ready will create excessive heat. At best it will increase gear whine, they will in any event be weaker, and your worst outcome is failure.

Lets go back to that 20 hours I mentioned. A typical car will go around 500 miles during that time. Most of you are probably too young to have changed gears on your cars. Those that have will recall that Motive, or whoever made your gears, will recommend something like 400 to 500 miles before full load operation. They will tell you to heat cycle the gears when you first install them by driving a short distance and then stopping for a time period. More or less 3 heat/cooling cycles and then you're told to vary your speeds and limit load, gradually increasing load as you get to their recommended full throttle mileage.

Anyone notice how it used to be your break-in was 500 miles, almost everywhere? That isn't an accident, that's when the longest directed break-in operation item, your ring and pinion, will be fully in service.

Why the 1000 mile thing you see nowadays? Things break more often when flogged, less often when babied. I don't think this, the data shows it to be true. Imagine you could increase profitability by simply changing a number that would have millions of owners babying their cars for an extra 500 miles.

I'm in Italy typing away in a wine bar; Mrs Crab has gone home ahead of me and I'm free to play. I apologize if I screwed that up on my phone.

Originally Posted by SW20S

I know a guy who leases high end cars and prides himself on never washing them or changing the oil. His response is "why would I, its a rental car". To me even if you are leasing a high end car, you're paying a lot. Why do you want to drive around in something filthy?! I had that GLS450 loaner for 8 days...I washed it because it was filthy.



Break in periods are outdated. Personally I think AMG suggests that to add to the allure that the car is special and handbuilt etc. Its like a Lexus ES requiring premium gas lol



Huge difference. I haven't driven a 740 but I have driven the 760 back to back with the i7 several times and the i7 feels totally different and better.

Originally Posted by SW20S

Thats the M70, the high performance version

Originally Posted by W205C43PFL

Ya I don't like the idea of just because it isn't yours, you should treat it poorly. I hate that mindset, hence why I am reluctant to buy lease return vehicles or to be a person that leases vehicles because I don't want to be one of them. I only buy cars new but depending on how the industry is going, I understand if I still want features (like physical buttons) or if I need or want dislike a certain automotive trend but MB is following, a used vehicle might be my only option. Or I can check out BMW like OP of course : )

Thanks for sharing your perspective on break-in.

Thanks for sharing your perspective on the i7 vs the regular ICE.

Originally Posted by Quietride

Can you imagine if someone bragged about not changing oil on their S-Class or 911?

Originally Posted by Quietride

That really speaks volumes about a person’s character. Unfortunately this is seen a lot in the EV world, especially among owners of certain brands like Audi. Owners will charge the vehicles to 100% at all times and let them sit, in direct opposition to the manuals and on-screen guidance.

“I paid off 100% of the car, and I won’t have it in a couple years.”

Can you imagine if someone bragged about not changing oil on their S-Class or 911?