Reposted - original was mistakenly in 1st Gen Forum

I thought that carbon buildup was a problem on all direct injected MINIs but on other threads I've read that it might not be a problem (or as much of one) with the N18 engine. I know the valve cover design and venting is different but some posts suggested that the N18 has a different head design and valve timing that is supposed to reduce the problem.

Are there any of you out there with the N18 that have actually had a carbon buildup diagnosis at a MINI dealership? How many out there have had no carbon buildup problems? What is the mileage when this occured or what is your current mileage if you've had no problems?

 

Subscribed to this thread and looking forward to some information on the topic.

 

Back in August, I took my 2011 Clubman S to Clint at Defenders of Speed; he pulled the intake manifold to look at the intake valves. These photos show that there is carbon accumulation on the valves of the N18 engine. At the time of the photos, the car had a bit less than 13k miles on it, and has always had Tier 1 premium fuel from Shell or Chevron.

 

Do you have an OCC? Plan to install one?

 

Bump

 

That's hardly any carbon build-up, and would not have a noticeable effect on performance or efficiency. Here's a before and after of a badly built-up car.





Unfortunately, a catch can does not significantly help in reducing build-up. We have done several cars with catch cans and there's no significant difference from cars without OCCs.

 

--

 

When we pulled the intake manifold off to have a look-see, Clint did say that the build up on my engine was not as bad as would be expected on an N14. He also observed that the N18's accumulation did not seem to be as gunky as that on the N14; to me it appears dryer than what I see in the photos posted of N14 engines. In any case, Clint used my car to test-fit the prototype for the Defenders of Speed N18 OCC:

 

The main reason I created this thread was to try to decide whether or not to install an OCC. I was ready to do it and created another thread to decide which one. It was on that thread that I heard that carbon buildup might not be a problem on the N18. For me, the jury is still out, but what Helix13mini says carries a lot of weight with me.

 

In your opinion, what can we do to fix that problem if the catch can isn't the solution?

 

Ha! That was the chunk of juicy in field info I was looking for I'm glad I got rid of mine and used the money towards race seats

 

Any N14's running water/meth/alky that have not experienced carbon build up (thanks to the injection)?

 

Rob,

The only way that YOU can help alleviate the problem is to clean your valves manually either with brushes or a walnut blasting service like Helix provides. Seafoam will offer you minimal help but will act like any fuel system cleaner as the product enters the combustion chamber.

Poor quality oil or oil that is severely run past its recommended change interval will also contribute to carbon issues. If you're using a full synthetic every 5-7K miles you're golden. Also, try to avoid taking short trips with your car without letting your engine warm up. Getting a little wild on the throttle helps a bit too. Engines do not like to be run at idle or extremely low loads all the time. They wanna work I followed this when my MINI was my daily driver and upon peeking in my intake ports my carbon buildup was about the same as what the cleaner N18 engine looked like above. Car had about 50,000 miles on the clock. I'll be cracking it open again this winter to see how things look again

 

Out of curiosity Shane how much does the walnut blaster cost? Either way now I will be using that money towards my I/C!

 

It appears that Helix and Clint are saying that, so far, it is not so much of a problem. I'm going to spend my money on go fast parts and pieces.

 

Ha, more than you'd like If you look up "media blasters" it will give you an idea. Not worth the cost if you're only doing it on your car and yours alone.

 

That's really not bad carbon buildup for that mileage. I did my FSI GTI with a riffle cleaning kit and got it completely cleaned, and it looked way worse than that after 10k. What are your driving habits? If you're putting on a lot of city miles, it looks great!

--Matt

 

Are you including cars with the N14 engine in that statement or just those with the N18? I'm hoping the former as I've debated for a year on whether or not to add an OCC to my MINI and and I'd really rather spend my funds on mods with less debatable performance.

 

In my experience, recirc cans in general are a waste of time. VTA catch cans work great though, if you can deal with the odor. BSH used to make one for these cars, but has stopped because of complaints about the mess and won't make any more of them.

--Matt

 

Good tips to know. I just dd my first full synthetic oil change at 5300 miles. My service indicator is showing the free one will be due at 9700 miles so I will continue doing one paid then one free every 5000 miles or so. I avoid short trips and commute 30 miles one way each day mostly at 70+ mph. I have about 3 miles before I get on I70 and almost always do a redline run down the on ramp at 5:30 a.m. Can't always do it on the way home though because of traffic. I do like to get into the upper part of the rev range quite a bit even if I don't get to the redline. I think I just ruled out installing an OCC. Thanks to all of you for the help.

 

There really isn't a fix beyond getting your valves and intake runners cleaned periodically.

 

Running water/meth injection immediately after a cleaning won't help keep it clean?? Seems like it would pay for itself in the long run if it works.

 

I think the issue with running meth is that most of it will evaporate when sprayed into a fine mist.

I am just not sold at all on running meth. Finding quality gas without ethanol is becoming somewhat difficult these days. I can't imagine trying to find race quality meth all the time. Screw that.

 

OK, so what I gather from this thread is that regardless what engine N14 or N18 - that an OCC is a waste of money and that those who sell em are just selling them because it's a doodad we'd buy? I think the OCC market just went in the dumper then, huh? <grumble> If this is the case, for lack of being able to do systemic research into the benefit (or not) of an OCC, kinda feel duped. Caveat Emptor

 

I don't think so.