PMW Ltd

Have your intake valves cleaned with our specialist Crushed Walnut Shell Blasting Tool

Modern engines are now often direct injection, this setup allows for improvements in fuel efficiency and performance as compared to conventional fuel injection. However, the disadvantage is that the regular cleaning of the intake valves by the fuel being sprayed on the back of them (indirect injection) does not happen any more.

Why should I have my inlet valves cleaned?

The intake valves are only in contact with air and blow-by gases from the crankcase breather system, in which substantial quantities of fuel and oil vapour can be found.

Over time, these form carbon deposits in the intake tract, as well as on the intake valves themselves. This is also referred to as carbonising and 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 lumpy idle, vibrations, poor throttle response and poor performance can be noticed.

On many vehicles, the inlet port becomes so badly contaminated with carbon build up that the port size can be reduced significantly (30-70%). This drastically reduces air flow into the engine and performance / economy is affected accordingly.

Because this happens over a prolonged period of time, the driver is not immediately aware of a problem and only once a serious running fault occurs is the root cause of the problem found or determined.

Unfortunately, this carbonising effect is an inevitable by-product of direct injection and cannot be prevented. The use of additives in the fuel itself is useless, as the fuel does not come into contact with the intake tract or the valves.

There are many cleaning processes that claim to 'simply' remove the carbon build up and restore performance and economy. However, we have yet to see one that works on a petrol direct injection engine!

What can be done?

In principle there are 2 methods to clean the intake valves and intake tracts of any direct injection engine.

The best and most robust way of cleaning inlet and exhaust valves while restoring valve seat sealing / integrity is to remove the cylinder head and carry out a total strip and re-build. However, in most cases this can be an unwelcome financial outlay when compared to the much lower priced walnut blasting alternative. It must be stressed this route is the 'belt and braces' approach.

The other method is the cleaning of the intake tract and valves of each cylinder with a blasting tool - this is what we can now offer at PMW.

Our Walnut Blasting Tool uses compressed air to inject fine walnut shell granules into the intake tract. These walnut granules hit the carbon build up at high speed and remove it entirely, while at the same time the material is soft enough to not cause any damage to the metal of the intake tract and the valves.

That is also the reason why no other material should be used for this method. The advantages of this method are obvious: on the one hand, a labour intensive removal of the cylinder head is unnecessary, on the other hand the method is very fast and effective once the inlet manifold has been removed and the valves moved into the correct position for the cleaning process.

Please note this option will clean the carbon away but will not restore valve to seat integrity if pitted, burned or worn.

What are the improvements from Walnut Blasting and will I notice?

This is the question that interests everyone, and yes, you will feel a difference!

If your vehicle is more than 3 years old, you'll almost certainly feel the throttle response of the car is noticeably better (without hesitation) and the idle will be as smooth as it was when the car was new, along with an improvement in engine power and fuel efficiency.

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