[elp_jc]

To keep the thread going, does anybody have a clue HOW the oil gets to the combustion chamber? It has to be thru the rings or valve guides, but why? I'd understand if we were running 5/20 oil, but with 10/60? Aren't our engines supposedly built to very close tolerances? Something doesn't add up.

I'm at 1,600 miles from the break-in service, and oil level still shows as full, which is good news since most of those miles have been highway, at high speeds (between 3,500 and 4K rpm), where this car supposedly burns more oil.

I'm thinking these engines drink more oil when pushed hard, rather than just revved high for highway travel, no? At the ton, it's revving over 4K rpm, but hardly breaking a sweat. And the funny thing is the engine doesn't sound like it's revving high, or even strained at all. Love driving this car on trips; it's a blast. Hope everybody had a great Thanksgiving .

[Cleveland]

Originally Posted by elp_jc

To keep the thread going, does anybody have a clue HOW the oil gets to the combustion chamber? It has to be thru the rings or valve guides, but why? I'd understand if we were running 5/20 oil, but with 10/60? Aren't our engines supposedly built to very close tolerances? Something doesn't add up.

The thing most M3 owners don't understand, is that our high-revving engines are very unique powerplants. They cannot be compared to the typical 3-series engines in the non-M cars. The engineering tolerance that are used to build these engines, does create a few necessary compromises that are unavoidable.

The biggest difference between a "M" engine and non-M engine, are the tolerances between the cylinder bore and the the Aluminum pistons /w/ nitrided cro-moly steel piston rings.

Since the S65B40 4.0 liter engine revs to 8400 rpms, the tolerances for piston ring-to-cylinder wall clearances have to more conservative than the tolerances for a normal 3-series engine.

One of the problems associated with in designing a high performance engine with a 8400 redline, is the intense heat that is generated at full load.

You have to engineer in a small relief tolerance, so the piston does not SEIZE inside the cylinder bore.

All internal engine components are made of a wide variety of steel, titanium and magnesium alloys. These reciprocating engine parts are sliding inside smooth uncoated aluminum engine block cylinder bores. These different metal alloys all have different expansion and contraction rates when they heat up.

The BMW engineers have to accurately calculate a safe operating tolerance between all these parts at every temperature point between 0 degrees Fahrenheit and ~260 degrees Fahrenheit.

The biggest challenge for the engineers...is to find a happy medium where the engine will not seize under the most intense testing conditions, while also minimizing the blowby of oil past the piston rings.

That happy medium is why we are told NOT to rev the engine before the engine reaches it's normal operating temperature. (~220 degrees Fahrenheit)

If you rev the engine too high (before it has reached it's normal operation temperature), you will be forcing some oil residual past the outer piston rings into the combustion chamber. (where it is burned as a fuel source)

That is where you 'lose' oil when the engine is cold.

When the engine is operated at extremely high rpms for long periods of time, the break-in procedure will determine whether or not you lose a noticeable amount of oil over time.

Some M engines will lose oil, while others will not.

It all comes down to how well the piston rings were worn-in upon initial break-in.

If the break-in was successful, the edges of the piston rings will seal properly with the cylinder walls to create a very tight seal. But if the edges of the piston rings did not wear-in properly...you will not have a good seal. (resulting in moderate to severe oil consumption)

[AMPowerJ]

Nice info. Thanks. So if I understand you correctly if you rev your engine before it is fully warm you will most likely just burn more oil but not necessarily harm it? I don't ever do this but I am curious.

[elp_jc]

Originally Posted by Cleveland

Since the S65B40 4.0 liter engine revs to 8400 rpms, the tolerances for piston ring-to-cylinder wall clearances have to more conservative than the tolerances for a normal 3-series engine.

Isn't piston speed the real variable? Don't have engine dimensions handy, but a long-stroke piston could be travelling at the same speed at 7K rpm as a short-stroke one at 8,400 rpm, no? Both should generate the same amount of heat, correct? Furthermore, with an appropriate cooling system that shouldn't be an issue anyway. And hey, motorcycles rev to the moon compared to the S65 engine, and mine have never burned any oil.

Having said that, what you said actually makes sense, even if I don't know why. Maybe the S65 has forged pistons that behave differently, or titanium connecting rods, etc. I don't believe our engines even have the former, but as long as oil consumption is not over the top, I don't have an issue with that. Heck, even my 2 new Hondas consume oil too, something that never happened to me before with any new car. My guess is sloppy quality and/or looser tolerances for cheaper costs, but could be wrong. Thanks a lot for your insight buddy .

[DryFly]

I just put in my first "extra" qt of oil today at 7.2k mi. (last change at 1200mi service).

[Niels E46 M3]

Originally Posted by Cleveland

Good solid info.

At 8800 miles on the current oil, I assume you are doing a fresh oil change soon?

Yes, will be getting fluids changed as service interval approaches. I missed the midway point on this interval,but all future service intervals will have an "inbetween" fluid change.

[King Tut]

Still no option for none on this poll. I've had my 1,200 mile service and 1 year ownership oil change. I lost no oil over either of those periods. The car has about 9,000 miles on it.

[buzz1515]

Could anyone tell me total oil capacity for the 4.0 v8 2011?

Regards

[Cleveland]

Originally Posted by buzz1515

Could anyone tell me total oil capacity for the 4.0 v8 2011?

Regards

BMWtechinfo.com states the E9x M3's 4.0L V8 oil capacity is 8.8 liters. (9.3 U.S. quarts)

[foolio]

Usually around 7-8k miles on an oil change I have to add a liter. I try to change my oil every 7-8k miles.