Carbon build up explained

George Smooth

///Member
Since I am offering a cleaning service I though I should do a write up on what exactly this carbon build up is and why it occurs.

Due to modern unburned hydrocarbon regulations, vapors from the crankcase are usually vented into the intake stream in order to prevent oil droplets from escaping through the exhaust. In a port injection traditional engine, these droplets are ‘washed off’ the neck of the intake valve by a relatively constant stream of fuel. In a DI (direct injection) engine, the gasoline doesn’t touch the intake side of the valve. As a result, the droplets have a tendency to bake onto the valve and cause significant carbon deposits causing a reduction in performance, rough idling, difficulty starting and eventually bad sealing of the valves. To add to this effect, many advanced DI engines also include exhaust gas recirculation in order to lean out the combustion mixture and reduce in-cylinder temperatures for certain combustion modes (reducing NOx emissions). Since DI combustion has the ability to produce far more soot than premixed combustion (port injection), the problem is magnified.
Even more alarming is that these deposits can dislodge and damage other downstream components (turbochargers, catalytic converters, etc.). Manufacturers have added systems to capture these oil droplets and particulates, but no system is 100% effective. As a result, there are many disappointed early adopters with large repair bills. Even diesel engines haven’t been immune to these issues.
Symptoms of carbon build up are typically:
Gradual increase of consumption
Rough Idle
Detonation
Leaking valves
Power loss
Misfires
Engine check lights

Some pictures of various model cars to get a general idea of what it looks like.

2.0TFSI as found in Audi/Golf

20fsidirty.jpg


N54 X35i

n54dirty.jpg


Porsche Cayenne

porschecayennej.jpg


Peugot/ Mini

peugot.jpg


Mazda 2.3

mazda23l.jpg


[undefined=undefined]Our process in a Nutshell:[/undefined]
At Carbon Clean Services we have adopted a tried and tested method of cleaning the carbon of your valves and inlet ports. Walnut shell blasting has been used for the better part of the century to clean sensitive components ranging from pc boards to jet turbines. This is also important when used in the cylinder head of a vehicle as the majority are made of aluminum which is highly sensitive to surface changes.
Using the right size and density the walnut shell is blasted into the intake track using a BMW Tool creating a clean surface whilst preventing any damage to sensitive engine components. The process is as follows:
1. Removal of inlet manifold following manufacturers procedures
2. Inspection of the valves and rear of the throttle body
3. Closing of the valves on the port to be worked on by crankshaft rotation
4. The carbon blast procedure is conducted whilst simultaneously vacuuming carbon deposits and walnut shell. This procedure is totally self contained and does not create further clean-up work in the engine bay.
5. Repeat for the rest of the ports
6. The inlet manifold is then replaced using new factory manufactured gaskets.
Carbon Clean Services uses this process as it is both cost and time affective guaranteeing a same day turnaround in order to get the vehicle back on the road. Other methods currently used necessitate the use of strong chemicals and metal brushes. This unorthodox method requires the inlet to be soaked overnight creating both a time delay for the customer as well as facing corrosive risks on aluminum components.

Clean and polished
cylinder2clean12sec.jpg
 

moranor@axis

///Member
Official Advertiser
all that money spent on making perfectly flowing valves... only they have them covered in gunk :yuck:
 

Philip Foglar

///Member
Fantastic write-up and new service George!!

So I gather this is ideally a clean intake?

IMG_5718.jpg


Had my 330i's intake off a while back and this is what the intakes looked like - photos don't show the valves lower down, but they were the same as the rest of the intake surfaces...

IMG_5715.jpg


So for the DI engines, (as in the N54/N55) an oil catch can would help prevent this over time too, but not totally?
 

George Smooth

///Member
Philip Foglar said:
Fantastic write-up and new service George!!

So I gather this is ideally a clean intake?


Had my 330i's intake off a while back and this is what the intakes looked like - photos don't show the valves lower down, but they were the same as the rest of the intake surfaces...


So for the DI engines, (as in the N54/N55) an oil catch can would help prevent this over time too, but not totally?

Those intakes look 100%. You can nearly lick them. :rollsmile:

The oil catch cans as well as methanol have been shown to be help but no real quantified improvement. Most internet threads I have seen do not even consider them a help at all. Remember that with a oil catch can you capturing hot oil vapor that will turn to liquid due to the drop of temp in the catch can. So from what it catches a good percentage was going into the motor anyway. Its the little bits that are sticking over many km's that does the damage.
 

UpNcOmiNg!

Events Organiser
Thanks for that! Well written, even an idiot like me can understand that! :thumbs:


What was the mileage and mods on that n54? Out of interest
 

George Smooth

///Member
UpNcOmiNg! said:
Thanks for that! Well written, even an idiot like me can understand that! :thumbs:


What was the mileage and mods on that n54? Out of interest



That car was on 72,000km. There isn't really a trend related to mileage. From around 40,000km it starts building up properly. My car at 45,000km with meth was pretty bad. I have scoped the valves and am experimenting with some chemical cleaners at the moment to see if anything that is available can dent it. So far the two that I have tested have failed and there are two more brands to go. I am hoping one of them will at least pass for regular maintenance after the initial manual walnut clean. This will be more essential for diesel owners as the whole intake tract gets affected.
 

Zack

///Member
Some of those look really bad. :yuck:

Great write up. Question though... All these things in the shops that advertise cleaning carbon build up. Does those really work or make differences in the build up?
 

badboizn

Member
George Smooth said:
UpNcOmiNg! said:
Thanks for that! Well written, even an idiot like me can understand that! :thumbs:


What was the mileage and mods on that n54? Out of interest



That car was on 72,000km. There isn't really a trend related to mileage. From around 40,000km it starts building up properly. My car at 45,000km with meth was pretty bad. I have scoped the valves and am experimenting with some chemical cleaners at the moment to see if anything that is available can dent it. So far the two that I have tested have failed and there are two more brands to go. I am hoping one of them will at least pass for regular maintenance after the initial manual walnut clean. This will be more essential for diesel owners as the whole intake tract gets affected.



Are you able to do this carbon clean on an E30 M20 engine and what whould be the costs?
 

George Smooth

///Member
Zack said:
Some of those look really bad. :yuck:

Great write up. Question though... All these things in the shops that advertise cleaning carbon build up. Does those really work or make differences in the build up?

I am doing a diesel specific thread in which I will answer your question thoroughly. In a nutshell what is advertised and sold in the shops is mostly for fuel system treatment. The idea on those is that it keeps the injectors free of carbon. I had a car tested that used it and the injectors where not in very good shape but I reserve judgement until more products are tested. Its a lengthy process as each time the treatment must get applied and then the vehicle must do some mileage thereafter removing the injectors and testing them again. At the moment ultrasonic cleaning is the only proven solution.
As for the intake if its bad enough no chemical will clean the soot build up. First time round will require a physical clean of the intake system and thereafter a chemical treatment needs to get used for maintenance. We are at this stage at the moment deciding on which chemical treatment is most cost affective. Its a lengthy process as testing is done over time and the sample vehicles we have can only do so much mileage.
Here is some pics of a 1.9tdi we did in Maritzburg with 128,000km.

19tdi.jpg


19tdiintake2.jpg


19tdimanifold.jpg


This car received a sea foam treatment twice prior to taking the pics hence the conclusion that once its bad enough physical work needs to be done.
 

George Smooth

///Member
skiet said:
Does BMW do this under motorplan if I specify it to them?

BMW's position is that they will work on the car only if there is a fault present. Its not something you can request to be done. Chances are that when serious problems are caused you will be out of motorplan.
 

George Smooth

///Member
badboizn said:
George Smooth said:
UpNcOmiNg! said:
Thanks for that! Well written, even an idiot like me can understand that! :thumbs:


What was the mileage and mods on that n54? Out of interest



That car was on 72,000km. There isn't really a trend related to mileage. From around 40,000km it starts building up properly. My car at 45,000km with meth was pretty bad. I have scoped the valves and am experimenting with some chemical cleaners at the moment to see if anything that is available can dent it. So far the two that I have tested have failed and there are two more brands to go. I am hoping one of them will at least pass for regular maintenance after the initial manual walnut clean. This will be more essential for diesel owners as the whole intake tract gets affected.



Are you able to do this carbon clean on an E30 M20 engine and what whould be the costs?



The M20 will eventually have carbon build up in the combustion chamber. The valves and intake stay relatively clean as the injectors spray onto them. There is also no recirculation valves pushing oil into the intake. We are working on a decarboniser for the combustion chamber but its not ready for release.
 

Sleeper135i

Member
George, is there a viable way to disconnect the crankcase from venting to the intake and preventing oil buildup completely? vent to atmosphere?
 

Philip Foglar

///Member
George Smooth said:
Those intakes look 100%. You can nearly lick them. :rollsmile:

The oil catch cans as well as methanol have been shown to be help but no real quantified improvement. Most internet threads I have seen do not even consider them a help at all. Remember that with a oil catch can you capturing hot oil vapor that will turn to liquid due to the drop of temp in the catch can. So from what it catches a good percentage was going into the motor anyway. Its the little bits that are sticking over many km's that does the damage.

Thanks! Wasn't sure what to expect when I opened it up, but pretty impressed, then again, only 67k km...

Saw a couple of other oversees threads showing N54/N55 carbon build-up, looks really scary bad!

George Smooth said:
skiet said:
Does BMW do this under motorplan if I specify it to them?

BMW's position is that they will work on the car only if there is a fault present. Its not something you can request to be done. Chances are that when serious problems are caused you will be out of motorplan.

Plus I don't think I would let them do this - rather a specialist like yourself, this is not a job that can be rushed the way the agents would typically.

BTW, have often read about the use of Sea Foam which personally I am not familiar with, but seeing how this is done on YouTube vids makes it look really risky!!
 

George Smooth

///Member
Sleeper135i said:
George, is there a viable way to disconnect the crankcase from venting to the intake and preventing oil buildup completely? vent to atmosphere?

I haven't looked at it carefully enough to say how safe it is. There is evidence that cars with increased crankcase pressure have smokey turbos and it affects the oil return eventually messing up the turbo. Decreasing it has got unknown affects which I wouldn't mess with. A lot of guys that have even fitted a catch can encounter some or other problem due to changes with pressures.
 
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