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 fuel 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
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
[undefined=undefined]Our process in a Nutshell:[/undefined]
At Carbon Doctor 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 Blasting 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. Further more carbon is not completely cleaned and small deposits left behind will increase build up exponentially as they create a trap for the next cycle of build up.
Clean and polished