These often stick to dirt and oil deposits and are transfer to the engine during re-assembly to disastrous effect. Even proper washing, or the use of steeping heads in toxic chemical baths, is expensive and time consuming while still not promising a correct preparation.

The only way to ensure safe and complete cleaning is through a mechanical effect associated with a decarboniser. This effect is achieved by the Serdi wmu90 by means of micro-bubbles generated by very high frequency ultrasonic waves and will secure elimination of carbon deposits in cavities and conducts even in the most inaccessible places.

The head is placed in a diluted fluid decarbonising agent, developed by Serdi and a well known international manufacturer. The working temperature is set at between 80 to 85 degrees celsius to give excellent results and restore the bright look of aluminium surfaces and the head treated for 10 to 15 minutes. Head size capacity easily accepts up to a Jaguar straight 6, for example.

The head is then rinsed with a high pressure clean water jet and dried before performance work or unleaded conversion takes place.