[craina]

Originally Posted by PrematureApex

Known to? Again, that's for preventing/slowing exhaust side build up, not intake side which we're talking about. Track only N54s (and even N55s) have the issue.

Yes, known to. I've read it all over the internet and I tend to believe what I read on the internet.

[JohnNC-M2CS]

Per BG's website, there is a professionally applied 2-part cleaner that will help keep injector tips and valves free of deposits:

"BG Gasoline Direct Injection Cleaner
PN 271 & 272
BG Gasoline Direct Injection Cleaner is a two-part cleaning process formulated to soften and disperse baked-on deposits that accumulate on intake valves of direct injected engines.

Direct injection engine deposits create a unique problem. Because the deposits form on the injector tip, the spray pattern becomes deformed. This causes fuel to ignite prematurely, producing a pinging and knocking. Left unchecked, these deposits begin to form on intake valves as well, dealing a serious blow to fuel economy and vehicle performance.

BG Gasoline Direct Injection Cleaner dissolves hardened fuel deposits that accumulate on injector tips and intake valves. Installed by a professional, it restores lost engine performance and fuel economy.

BG Gasoline Direct Injection Service
BG Gasoline Direct Injection Cleaner is part of the BG Gasoline Direct Injection Service."

[PrematureApex]

Originally Posted by JohnVa1M

Per BG's website, there is a professionally applied 2-part cleaner that will help keep injector tips and valves free of deposits:

"BG Gasoline Direct Injection Cleaner
PN 271 & 272
BG Gasoline Direct Injection Cleaner is a two-part cleaning process formulated to soften and disperse baked-on deposits that accumulate on intake valves of direct injected engines.

Direct injection engine deposits create a unique problem. Because the deposits form on the injector tip, the spray pattern becomes deformed. This causes fuel to ignite prematurely, producing a pinging and knocking. Left unchecked, these deposits begin to form on intake valves as well, dealing a serious blow to fuel economy and vehicle performance.

BG Gasoline Direct Injection Cleaner dissolves hardened fuel deposits that accumulate on injector tips and intake valves. Installed by a professional, it restores lost engine performance and fuel economy.

BG Gasoline Direct Injection Service
BG Gasoline Direct Injection Cleaner is part of the BG Gasoline Direct Injection Service."

Holy shit people.

The N54 (and to a lesser extent, the N55) carbon build up problem is ON THE BACK SIDE of the intake valves. They don't see fuel.

There is no problem on the injector tips, or on the fronts of the valves.

Stop reading websites and start reading technical forums.

Better yet, you own an N54...so pop the manifold off yourself and tell me (us) where the deposits are.

C/N: The reputation of BMW forums in general is well-deserved.

[swilliams]

I'm not going to worry about it. Most owners will ditch their M2 for the next greatest model before it becomes an issue. In my mind, if the M2 is worth keeping for 100k+ miles it will be worth the cost to check the intake valves and clean them for another 100k miles.

[KevM2]

Originally Posted by paradoxical3

This won't be an issue. I visually inspected my valves at 70k miles of hard use and there was no point to clean them; they were so clean that the shop said that I wouldn't even be able to tell a difference if we blasted them. The PCV system is way better on the N55 than it is on the N54. The shop walnut blasts many N54s (several a week) and have never come across a N55 that was worth doing it under 100k miles.

Old thread but mind me asking what oil you used in the car? Also what kind of driving was the car mostly used for (track, daily driver or combination?)

[G80indy]

Another answer is keep your oil clean

[SchnellerM2C]

I hope I might shed some light on this issue...

The problem starts with the recirculation of crankcase blow by gases back into the intake.

As a quick review, in all engines, the combustion chamber isn't a perfect seal. On healthy motors, 5% of what's ignited in the cylinder "blows by" the piston rings & into the oil pan.

In the "old days" of carbureted engines, this blow by was vented into the atmosphere. As emissions tightened and injection systems demanded a sealed up crankcase, this blow by was recirculated back into the intake to be recycled & eventually treated by the CAT converters.

As blow by gases pass through the crank & timing chain areas, they pick up & carry along with them, oil droplets. These oil droplets end up in the intake where they would eventually get washed by port injectors into the combustion chambers.

This "extra" oil increased emissions, as it was in effect, unmetered fuel. To reduce this effect, we had the introduction of externally located oil separators in the M54 engines for example, which eventually wound up in the valve covers of the n52+ engine family.

While these oil separators "minimize" oil in the intake, oil still ends up there, especially as the oil separators age & become somewhat clogged. Additionally, we now we have direct injection, so that oil in the intake is no longer "washed" from the intake ports & intake valves.

So what happens to this oil? Well, when exposed to engine heat in the cylinder head intake ports or exhaust valves, it ignites leaving carbon build up behind. If you happen to be using an engine oil with a flashpoint of less than 400 degrees C, you'll eventually clog your engines intake ports & valves over time.

Everyone's shopping for the cheapest oil service. You get what you pay for.

When other shops started doing all sorts of walnut shell intake blasting on N54/N55 engines, we geared up & bought the equipment. However, we've only "had" to clean 3 vehicle engine ports and those were on cars that came to us from outside of our customer base.

On cars that we've serviced for years, we have not seen a significant build up of intake port deposits. Hence that blasting equipment along with 4 boxes of walnut shells have been collecting dust in the shop .

Along with flash point, it's also important to change a turbocharged engine's oil every 5K miles. Ever notice how even at 5K miles a turbocharged engine's oil is black while on a NA engine one can still see through the oil? Turbos are very tough on oil and flash point decreases over time. Considering that the best oils will have a flashpoint nearing 500 degrees F, and turbos reach temps of about 1000+ degrees F, some of that oil is ignited as it lubricates the turbo. This will leave abrasive carbon deposits in your oil, some of which the filter won't capture. Overtime, this situation will increase internal engine wear .

Of the four N55 motors we've seen that spun rod bearings, all had oil services in the 12-15K mile range with at least one oil change interval that pushed over 18K miles. The worst was a 335i where the first oil service was at 24K miles and the second at nearly 50K miles. The engine went kaboom at 66K. Analysis showed the oil pump impeller bearings were worn allowing the impeller to tilt & shave aluminum from the pump housing which went straight to the bearings

Bottom line, high flash point synthetic oil + good oil filter + 5K mile service interval = low intake deposits & low internal engine wear

[mssVT98]

Originally Posted by SchnellerM2C

Bottom line, high flash point synthetic oil + good oil filter + 5K mile service interval = low intake deposits & low internal engine wear

This is great info, thanks for posting. Not to open the "best oil" can of worms, but do you have any recommendations for high flash point oils? It doesn't seem like that's something easily identified from product labels, etc.

[bmwstephen]

I for one would start out with a slightly thicker oil such as 5w40, than what BMW recommends (0w30). Liquid moly Molygen did wonders on my e36 when driving the piss out of them and those cars don't even have oil coolers.

[David1]

Oil weight has no bearing on carbon build up. Oil contamination does. When the oil seperation chambers clog up in the valve cover, then the carbon realy starts. change the oil more often than what BMW says, drive and enjoy and move on with life. At 75k to 100k on this version of the N55 just inspect the valves. If they need cleaning replace the valve cover while you’re at it since it will probably be seeping anyways and you can’t clean the pcv chambers.

[SchnellerM2C]

Group,

I made a quick edit to my previous post in this thread...

Engine oil flash point & turbo operating temps should have been in degrees "F" not "C". Sorry, but this has been corrected.

Relative to finding engine oil flash point values, one needs to do some digging.

Liqui Moly, for example, only lists this specification on their downloadable product specification sheet (along w/ a NOACK Value)

Red Line only lists a NOACK Value which is a measure of an oil's volatility.
If you'd like to get into the weeds on that, there's more info here:
https://www.machinerylubrication.com...ty-flash-point

and here...

https://bobistheoilguy.com/forums/th...grades.326562/

Relative to NOACK values, I think you'd want your oil to be below 10%.

A test I might suggest is this...
Send a virgin sample of the oil you use to Blackstone for testing. They'll provide you w/ a base flashpoint value for the oil new out of the bottle.
After 5K miles of use, send them a used sample to see how much the flashpoint has degraded.

This might be helpful in your choice of oils and determining a service interval given your use.

FYI, here's a baseline for BMW's 0w30 Twin Power Turbo Oil:
https://f87.bimmerpost.com/forums/sh....php?t=1818756

[bmwstephen]

not an m2 n55 oil analysis, but both my e36 m3 (s50) and GLK 350 w/DI uses liquid moly 5w40 molygen (green bottle). The oil analysis suggests flash point is well above 375F and other properties are holding strong.

The M3's oil analysis was done after 5K of hard driving at 130k miles. Been using liquid moly since I acquired it 10 years ago at 113k miles changed at 5k intervals.



the GLK was around 10K of daily driving with start/stop by my wife. has around 110K miles on it (been using liquid moly at 10k mile intervals since I got it at 70k miles)



I bought my current M2 has the OEM 0w30 right now so it will be another 2 intervals before I can sample liquid moly into it but thats what I intend to use in my next oil change.

[G80indy]

Redline Euro series looks good for low volatility, and low ash….
link

[///MPhatic]

The standard Pennzoil Platinum Euro 5w40 that everyone is using, changed at 5K miles/once a year has worked for many high-mileage cars already, no need to change to a different type.