WOW. I had no idea my car had the power it does! Losing power slowly over time has caused me to not realize how much I had actually lost! When I started realizing that WOT pulls through gears wouldn't yield 1-2 or 2-3 chirps like I used to, and that my torque steer was gone, I figured it had something to do with tires... well, tonight, all that power is back. Haven't been pushed back into my seat like this since (who knows how long). Maybe never, since I've added more go fast parts since my initial tune.

What am I talking about? I realized that methanol was doing absolutely nothing to break up any carbon build up. In fact, soaking it in carb cleaner for 30 minutes yielded not much progress. It really relied on scraping and brushing with metal brushes/picks. Also, I knew I would be finding some build up when pulling the manifold today, but not like this:

One valve in Cyl 1 was the worst. I only had toothbrush style horiztonal bristles for my brass/steel brushes, and my nylon ones were the pipe cleaner like bristles. I wish I had those in metal, as cleaning the intake valve was the hardest, and the nylon brushes did not do much good. I ended up using a thin long flathead to lightly scrape the backsides of the intake valves and did my best. Resoaked them in carb cleaner again and did a final dry and spray.

Before:






After some scraping/soaking:


Finished. but could have done better with better tools. But I followed the 80/20 rule.. basically getting the last bits would only yield a small insignificant benefit compared to everything else thats been removed.






Example of some of the chunks coming off I was able to pick out, huge chunks would come flying out with intermittent air compressor blowing.

 

wow that looked terrible but looks like you did an amazing job cleaning it up. how many miles were on your car when you performed this and what were your driving habits like?

Lastly is there a write-up you followed to remove the intake manifold? is it easy to remove or will it take a long time (2+ hrs to remove).

Thanks for the photos.

 

How long did you have the aquamist on the car? Interesting that it didn't help reduce the buildup...

 

Gah!! The horror!
Is this with or without having a oil catch can and/or PVC delete?

 

https://www.northamericanmotoring.co...right-way.html


It can be a controversial claim.
https://www.northamericanmotoring.co...ml#post3141289

 

this is awesome proof but you will still get people seafoaming every 5000miles.

 

How about we compare to a member who seafoams every 5k miles... compared to when he went to do the walnut blasting... He can chime in if he wants as well. (I believe he has right around the same mileage as me, 70ish-75k miles, its an '07, mines an '08)

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Besides my Cyl 1 which was AWFUL, they don't look too much better than my Cyl 2-3 before I cleaned them. Also, this is a good comparison to show how much better a media blasting cleaning can be much more effective than manual scraping. Its evident I still have lots of carbon left on the valves, though compared to before, its magnitudes better.

No catch can, no PCV block, 70k miles. '08 S. Methanol for the last 10k miles.

Driving habits- No short drives, ever. Always let the car warm up to temp before getting into boost. During every drive, after it warms up to temp (I account for oil as well as water temp), I roll out the Revs at least once during the drive (WOT). So, imo, its the best scenario for clearing any deposits, but, again, this applies only so much to a DI car.

The problem with this myth that w/m will clean your valves is... w/m only sprays (for a short amount of time) when you are heavily on the throttle (depending on your injector duty cycle/boost setting for pump activation), which, isn't when you have the most oil blow by. The rest of the time, driving normally/cruising, and during warm up, there is no w/m to clean the valves.

The oil blow by occurs heavily when the car is cold, and the EGR is active (emissions control bs). Add it to oil thats not up to temp, doesn't flow well.

OCC and PCV block off are going in.

 

Awesome thread!

Is the PCV block off required when doing the OCC? Also what method are you going with for doing the PCV block off?

 

I agree that W/M will not remove large amounts of carbon build up that has accumulated over several thousand miles. It will however greatly reduce future buildup.

 

There is no EGR in these cars.

And blow-by gasses are pushed into your crank case every time a piston's combustion chamber is ignited; i.e., you get more blow-by with higher revs, it's not so much related to temperature.


An OCC is required if you block the PCV hose, but blocking the PCV hose is not required for having an OCC.

 

Installed water/meth when jcw had 500 miles and at 11000 miles had zero carbon deposits.

 

I want to do this with my new JCW, but fear of the warranty has me thinking otherwise. But then this thread pretty much shows it is a pay me now, pay me later situation.

 

My mini dealer was ok with water/meth.

 

EGR is the thing most people are forgetting in this whole mess...

While the Prince engine doesn't have EGR specifically, it does have cam phasing control over the intake valves (N14 VANOS) or intake+exhaust valves (N18 VANOS) that allows for valve overlap and exhaust reversion into the intake tract.

You will see that the worst of the deposits are right at the bottom of the intake runners, where they are hottest (but not hot enough to make carbon from oil). If it was oil causing this, it would be depositing at the colder areas (throttle body, intake manifold, etc.) not hotter areas (where the oil would flow more easily). Let's say there is 5-10% EGR "reversion" flow - guess what, that's the first 1-2" of the intake runner where most of the deposits are.

Since the EGR functionality also happens when any Water/Meth injection would be inactive (low, cruising load), the deposits happen and can't be controlled. In a normal motor, fuel would be cleaning this area all the time (as has been said many times).

That's my theory as to why its so bad on this engine. Other factors (blow-by, etc.) will pay a roll, but we may be barking up the wrong tree for much of this problem.

-Charlie

PS. This means that there could conceivably be an ECU re-flash that reduces the carbon build-up - but it would come at the expense of reduced gas mileage and increased emissions.

 

Awesome, so we've engineered a generation of cars that have greater mpg, lower emissions but at the cost of long term functionality. Oops...

 

I think that engineering was mandated by the government to meet higher fuel standards and lower emission standards. Now the government needs to mandate free walnut shell blasting for 150k miles on each motor. We need big brother!

(not)

 

It was all good (ish) before direct injection.

You could go the Toyota/Lexus route and do dual injection (direct+port)...

-Charlie

 

You someone explain to me what water / meth injection is, how it works, where I can buy one for the mini, how much it costs to install and run? I would be very interested but I honestly don't have a clue about it.

The only meth injection I know of is from watching episodes of "Breaking Bad" and I highly suspect that type of meth is different.

 

Yeah, search for Methanol Injection, not Methamphetamine injection.

-Charlie

 

Check out http://howertonengineering.net/
Their Aquamist systems are the water/meth systems of choice.

 

I don't think anyone is saying oil causes the carbon buildup (if anyone is, they're probably just incorrectly latching on to Oil Catch Can). The prevailing theory has been the re-circulation of carbon (soot, really) suspended in blow-by gasses (which are basically the same thing as exhaust gasses, the difference being which path they take to exit the combustion chamber). The VANOS overlap you bring up is interesting, but one would think we would see more people in here saying that blocking their PCV hose didn't stop the carbon buildup, were VANOS overlap a significant contributor to the issue.

I've cataloged my carbon buildup issues in these forums elsewhere, and last month I had my MCS in for the walnut blasting service after getting multiple CELs due to misfires. Part of that walnut service was to update software in the car (wasn't expecting that). The technician said he thought it was to make the ECU less sensitive to misfires (sounded fishy to me at the time)... but perhaps MINI is hitting VANOS with instead? All I know is I'd love an opportunity to pick the brain of an actual BMW engineer who knows what's really going on.

 

My understanding on the oil catch can thing was that people are expecting oil vapors in the PCV flow, not carbon/etc. from combustion. (well, that's what *I* expect) Fast moving parts inside the engine get some oil vapors whipped up in there and then blow-by carries it out of the engine.

As an aside, the N18 engine still has the same style (dual) PCV - the rear PCV (to the manifold) is now internal to the head instead of external to keep the manifold and throttle body from icing up - and now you can't block it like people have been doing with the Boost Tap and other parts on the N14 engine.

I would also be very interested in the true internal BMW understanding of this problem, as it is also happening on the direct injected BMW engines.

The last thing - I haven't seen convincing evidence yet that catch cans really do fix the problem... I'd like to read some success stories if you know of any specific threads. (i.e. needed cleanings every 15k before oil catch can, 40k since last cleaning with catch can and things are all good) I'm just not sure if people have put enough miles on their cars since catch cans to really know. I very well could have missed something though.

-Charlie

 

The whole joie de vivre of a PCV system is to recirculate blow-by from previous combustion cycles back to the combustion chamber. There may be oil vapors in the crankcase that get sent that way as well, but that's not why the system is there, and those aren't going to lend themselves to carbon buildup as easily. Think 1800s chimney sweep... there's a lot of easy carbon buildup to be had from airborne byproducts of incomplete combustion.

Yes, I know. If you go back to the original conversations about that, the similarly re-designed intake manifold for the N14, and the controversy of whether or not the PCV hose had been incorporated into the valve cover, you'll find I was somewhat in the thick of it all.

Oh, yeah, and it's not just a BMW issue; it's a direct injection issue in general. I've read the exact same carbon buildup complaints regarding Audis, Lexuses (Lexi?), Mercs, VWs, Hyundais, etc.

Ooooo, I went looking for an old newspaper clipping I've posted previously in these forums about carbon buildup and DI engines, and found this (relatively) new article I hadn't seen before. Quite interesting for a number of reasons!

1. DI engines in US models (Ford, GM) seem to have been designed more intelligently (wasn't expecting that)
2. This "more intelligently" stuff apparently deals a lot with valve timing ... appears to lend some credence to the VANOS overlap tweaking theory, though the article doesn't mention PCV systems when taking about "dirty" intake design (and PCV systems are dirty)
3. Apparently manufacturers with these "dirty" intake designs are beginning to reign it in, and the problem is projected to be sorted across the board in a few years time.

I had thought DI engines were being found out as a lost cause these last few years, but reading this article has damn near made me giddy as a school girl.

A catch can will only slow down carbon build up, not stop it completely. But, depending on the efficiency of the can and the setup, maybe slowing it down is enough.

 

I will stand by my statement that most of the contaminants we care about in the PCV system is oil vapor - but read on, I think we can come together on this one.
That comment was for others, not for you.
That is a *very* good article. The theories put forward in that article make a lot of sense. How about this: Oil vapors on the PCV system meet hot 'reversion EGR' gasses at the intake valves/ports. The mixing of hot gasses (low on oxygen) and hydrocarbons results in incomplete/dirty combustion (sort-of), leaving the hard carbon deposits on the valves. This leaves two ways to solve the problem - keep the PCV system clean (free of oil mist) or keep hot EGR flow to a minimum (not possible except by engine redesign).
All this ends up with a similar conclusion to what has come about already on the forums - since we can't control the EGR/hot gasses at the valves, at least try to control the excessive oil vapors in the PCV system. Uh oh, did I just come full circle?

-Charlie