Just had my valves blasted at 43K on my 2007 MCS. What is the consensus to reduce this problem in the future? Catch can, "blocks", chemical cleaning, some combo of the above or?
Thanks for your thoughts.

 

A catch can will not stop carbon build up on your intake valves.

PCV Block off's will not stop carbon build up on your intake valves.

If you have a fresh walnut blast, chemical treatment every so often MAY slow the carbon build up, but in itself will not prevent or cure it.

The reason this happens on DI cars and not PI cars is because there is no abrasive fuel washing over the back of the valves. Fuel is very coarse in nature and does a fantastic job of keeping the valve clean on PI cars.

So with that said, though I do not believe it's as abrasive as gasoline, Meth/water injection could very well cure it and some have claimed it does. So you would be installing something that gives a performance enhancement and potentially stopping carbon build up. The downside is it's not a cheap set up to do right, and it's a constant expense like washer fluid or oil changes.

Also, I'm fairly sure every single point I just made has been discussed along with some of the other threads you've made recently. I've found the search function on this site actually works really well.

 

I agree with Injected's comments above. My car had carbon cleaning just before I bought it. I put on an OCC and blocked the rear PCV within a couple thousand miles. I just had to have the carbon removed 30k miles after I bought it. I've been pretty disciplined about maintenance and draining the OCC.

The water/meth sounds like a potential solution, but I don't know enough about it.

My recommendation is to plan on cleaning the valves every 25/30k miles as part of your routine maintenance plan. Sorry that I don't have a better solution.

Have fun,
Mike

 

What PSI should be used when walnut blasting?

Rob

 

The best medicine is frequent cleaning of the valves. That is the only way. Catch cans are a huge waste of money for the R56.

 

What does blocking the passenger side PCV accomplish? I'm really confused by this.

 

If you want to get technical .. there are no "fixes" to prevent the issue from happening again. You can slow the issue, and there are a plenty of people out there who try and will offer suggestions, but there is no fix.

 

Abrasive fuel? What grit would you guess it to be?

 

LOL...guess he meant to sat gasoline is a "SOLVENT"
Still kinda funny...

 

Yes, your gasoline has abrasive particles in it. Sorry if my term "abrasive" isn't to your liking, but it's accurate.

 

Gasoline has no abrasive particles in it.

If there were any, the fuel filter would take care of it.

Gasoline is a solvent. With port injection, it washes the oil mist off of the backs of the intake valves. With direct injection, it does nothing to keep the oil from the Positive Crankcase Ventilation system from building up on the backs of the intake valves.

An oil catch can slow the build up on an N-14 engine, but will do nothing on an N-18 engine.

There is a lot of discussion on these forums about this, if you use the search function.

The only way to remove carbon build up is to walnut blast the intake valves.

Dave

 

Is a '12 non-S Cooper PI?

 

Do you mean DI?

 

The question is the same, but on the opposite side. PI meaning Port Injection rather than DI meaning Direct Injection...

 

Smaller than the 3-5 micron filters located in the fuel injectors?

 

Good follow up.

Also the detergents in top tier gas are pretty good at their job. Unfortunately these don't make it across the valves either.

Water/meth injection can help. It can also cost you a new engine that comes to just a hair under $10k installed.

 

I was just trying to understand and confirm if and why the non-S cooper does not exhibit the carbon buildup that the S has.

 

It is a DI engine. Does not flow as much fuel nor run as hot. It will see the same symptoms but will take longer to build deposits.

 

You are absolutely correct. This issue is eating Audi & VW's lunch. Audi has tried all sorts of methods to addresses the problem with no success, except for regular cleaning. Can you imagine buying a $100,000+ RS8 and then every 25,000 miles more or less pay to have major invasive surgery to clean the valves, tubes, etc.

 

Nothing new but interesting read.
http://www.edmunds.com/autoobserver-...-adopters.html

 

Good read. Thanks for the link. I did not know some of the carbon buildup was due to the valve not closing quickly enough and allowing combustion byproducts back out. I thought it was all from the PCV system. I'm still unsure about blocking the passenger side PCV though...

 

NO. The non-S uses port injection (not direct injection and does not have a high pressure fuel pump).

 

I believe the N18 engines began the employment of dual vanos which more closely controls\manages the valve overlap thus reducing the problem somewhat (a la GM). I'm not sure there were any PCV changes with the N18, but I presume some, which makes the rapidity of build up less when compared to the N14.

 

Was not aware they changed the top end that much. Thks for the clarification.

 

Yes, there were major changes in the N-18 engine's PCV system, from the N-14's design.

The N-18 engine has internal passages in the head from the head cover/PCV valve to the intake ports, instead of a separate PCV hose from the head cover to the throttle body, as on the N-14 engine.

Dave