Ultrasonics: Redefining performance engine rebuilding

The process of rebuilding an engine can be a lengthy, difficult and delicate task. The use of an ultrasonic cleaner to clean the components reduces the time and effort required, while also ensuring that the process is effective and successful.

Whether you are a home mechanic or a garage mechanic rebuilding an automotive engine can be a delicate task. It is vital to that the components be both clean and reassembled correctly as failure to do so can result in a poor rebuild which is ultimately likely to fail in a much shorter time period or simply not run correctly right from the outset. This is particularly the case if the engine is a high performance engine designed for use on the track. Whether such track use is for competitive purposes or simply as a hobbie the importance of ensuring the rebuild is done correctly is crucial. Once the initial dismantling of the engine has taken place and the new parts are ready to be fitted it is essential to clean many of the components whilst off the vehicle. Although there are chemicals and aerosols designed to carry out carbon removal while the engine is complete they are no substitute for removing these tenacious deposits while the engine is broken down. This can be an extremely time consuming task as many of these residues will have been heated onto the components surface during operation making cleaning them off a difficult task. There are a number of solvent based products which can be purchased to carry this out but many require specialist enclosures in order for their use to be legal. Even with these solvents the results achieved can sometimes be questionable at the best of times with the part requiring extensive soaking and manual scrubbing to remove the deposits. This also means that a complete dis-assembly is needed to carry out the cleaning process which adds both time and effort to the task. If you're a home mechanic this is something that you always want to avoid if at all possible while in a garage it can increase the cost of a repair a great deal. However, ultrasonics offers a cost effective solution which will produce great cleaning results and often in a fraction of the time and with far less effort.

The process of ultrasonic cleaning uses high frequency sounds waves which are radiated through a liquid medium. These sound waves are created by peizo ceramic transducers which are bonded to the base of the ultrasonic bath. As an electrical current is passed through the two transducer crystal rings they become agitated and vibrate at around 40,000 times a second. This vibration converts the electrical energy to sound energy which is then transferred through the base of the tank into the liquid medium. As the sound waves pass through the fluid they cause the formation of microscopic bubbles. These bubbles continue to grow in size until they become unstable and cannot support their own density, causing them to implode. This is the phenomenon known as cavitation. As these bubbles collapse the surrounding cleaning fluid rushes in to fill the gaps, which creates an action similar to that of a scrubbing brush, but thousands of times a second per cubic centimetre. It is this process which gives ultrasonics is powerful cleaning action and makes it the most effective method for removing contaminants from hard substrates or complex shapes. This process can be further intensified by adding a cleaning detergent to the liquid. Ultrasonic detergents work on the same principle as a normal household detergent by aiding the loosening process. They also increase the saturation capacity of the liquid meaning it can hold more debris in solution so it cannot re-contaminate the item during removal from the ultrasonic tank. There are a variety of detergents available which can be used for various applications. Softer ferrous metals, such as aluminium, require a different detergent to steel as the harsher detergent can lead to surface pitting on soft metals. Speciality formulated carbon removal detergents easily lift of baked on debris without causing damage. Because the entire ultrasonic tank will contain cavitation bubbles it has the ability to penetrate areas which are unsighted or difficult to reach.

In Layman's terms; if an item is submerged within the cleaning liquid any surface area which is in contact with the medium will be exposed to cavitation, and therefore the cleaning action.

Here we look at some of the components which ultrasonic cleaning can improve the cleaning efficacy of and in a shorter time.

Cylinder heads have difficult to reach internal channels. For peak performance these channels where the air enter the engine need to be as clean and smooth as possible thus maximising the air flow to the combustion chamber. The oil cooling channels which run through the head and allow the oil to flow also need to be clean and free from potential blockages in order for the engine to gain sufficient cooling. These channels are subjected to high temperature contamination build up from both the combustion chamber and the engine oil. Typically deposits in these areas are carbon and coagulated oil. In the worst case scenario of an engine blow up, or a valve stem oil failure oil can also be forced backwards through the inlet manifold and become baked on in this notorious hard place to clean. In this situation the ability to clean without dismantling the head completely has obvious benefits. By placing the cylinder head, complete with valves and cams into an ultrasonic tank the cleaning action instantly reaches these channels and subjects the surface to a rigorous cleaning process, lifting off the deposits. Unlike alternative methods of cleaning it can take as little as ten minutes to removal these baked on residues with the cylinder head emerging in almost new condition. The minute gaps around the valves and through the valve guides are small enough for water particles to penetrate and if this occurs then cavitation will be occurring within these spaces, and ultimately the cleaning action.

Another component which is extremely difficult to clean effectively is that of fuel injectors. All modern engines use fuel injection systems as they are far more efficient than old style carbs. However, these small items have internal needles which become clogged over time. Cleaning agents which can be added to the fuel do clean them but not as efficiently as an ultrasonic process will. By placing injectors into an ultrasonic tank the internal channel of this needle will be subjected to cavitation and therefore ultrasonic cleaning. The process is gentle enough not to damage the internal elements of the injector as it breaks down any build up of fuel or dirt which passed through the fuel filter and made it into the injection system. The results of cleaning injectors in an ultrasonic cleaning system will be instantly visible with the fuel jet producing a cone shaped spray which leads to maximum fuel flow and efficiency.

Another component which is notoriously difficult to clean after an engine blow up is a turbocharger. Driven by the exhaust gases, which can reach over 800�C, the turbine wheel and housing will be exposed to any burning oil which is being forced from the combustion chamber. In many of today's high performance cars, the turbo will glow red hot when the engine is being driven hard which leads to the  turbine wheel becoming coated in oil and fuel residues as they travel en-route to the exhaust. These residues can become particularly difficult to remove because they are baked on at such high temperatures. The exhaust housing will also be subjected to these residues and often become coated. The very design of turbo housings makes them difficult to clean effectively, as they have either single or twin channels to direct the air onto the turbine wheel and the wastegate flap. The cleaning process used must ensure that no marks are left on the internal channel as this will disrupt the airflow resulting in reduced performance and air flow. Ultrasonic cleaning is especially effective for cleaning both of these parts as the turbine fins and smooth internal channel of the housing are easily penetrated by the liquid medium. Cleaning items like this will often require a longer cleaning cycle because the deposits are baked on in excess of 500'C. the risk of damage to the channel and impellers will be kept to a minimum and both items will emerge with the oil and fuel deposits removed, resulting in optimum flow through the housing onto the turbine wheel, and out through the exhaust downpipe. The clean fins will have less drag meaning improved performance and airflow, which can lead to a reduction in turbo lag. This is especially important in competition engines as lag can lead to loss of valuable tenths on lap times along with a reduced turbo life span.

These are just some of the areas which ultrasonic cleaning can be used when carrying out work on engines but its uses are far more diverse than this. It can be used to carry out cleaning of any metal components off a car. This can include brakes, differentials and universal joints. These all have difficult to reach areas which ultrasonic activity will occur in allowing them to be cleaned without the need for complete disassembly. This can be highly beneficial if any items simply requires cleaning before being reinstalled.

Ultrasonic cleaning also offers a number of benefits to the end user or business. Because it has the ability to clean items in a short time the running costs for an ultrasonic cleaner are low in terms of electricity and power consumption. In a typical operating environment the cleaning liquid will only need changing once a day meaning a reduction in water usage and the level of detergent dosing is often small with no more than 10% of the liquid being detergent.

With so many uses within an ultrasonic cleaner is a must for people in the reconditioning trade. It can greatly reduce the time required to clean, de-grease or de-carbonise components and without full disassembly making it an excellent choice, whether you are a performance engine manufacturer or a small engine reconditioner.