Walnut Blast Cleaning

At Burch Motor Works, we have the equipment and training to carry out Walnut Blast Cleaning. We carry out this procedure on several BMW and Mini engines. Please call to enquire whether you model/ engine may be affected and require this cleaning procedure.

Walnut blast cleaning

In principle there are two methods of cleaning the intake valves and intake tracts of any direct injection engine. A very elaborate and consequently expensive method is to completely take off the cylinder head and to have the valves lie in a very aggressive cleaning solution for at least 48 hours, after which they have to be cleaned manually as well in order to remove any remaining carbonising. The other method is the cleaning of the intake tract and valve of each cylinder with a blasting tool... This is where our new facilities come in! Our blasting tool uses pressurised air (usually 6-8 bar) to inject fine walnut shell granules into the intake tract. These granules hit the carbon dust at high speed and thus remove it entirely, while at the same time this material is soft enough not to damage the metal of the intake tract and the valves.

Carbon build-up symptons

This is not immediately bad for the engine, but over time can have a detrimental effect on its efficiency. If the valves are heavily carbonised, they may not close properly anymore, and symptoms such as a bumpy idle, vibrations and diminished throttle response can be observed; it may also contribute to increased oil consumption.

The carbonising process

Modern engines are often direct injection, as this process allows for advantages in fuel consumption as compared to conventional fuel injection, as well as yielding more power with an engine of identical displacement. However, the disadvantage of this is that the regular bathing and therefor cleaning of the intake valves by way of the fuel that they are exposed to does not happen any more. The intake valves are only in contact with air or rather blowby gases from the crankcase breathing circuit, in which substantial quantities of fuel and oil can be found. Over time, these lead to deposits of carbonised fuel and oil in the intake tract as well as on the intake valves themselves; this is also referred to as carbonising.