It is often said that the combustion chamber is the heart of any internal combustion engine, although the lungs might be an anatomically more accurate analogy. What is in no doubt though is that it has a fundamental bearing on the efficient operation of the engine; it is where we convert our chemical reagents into other substances and release energy in the process. The piston is an important part of this in any race engine. In a diesel engine, the combustion chamber is mostly formed in the...
With the push for ever-improved engine efficiency in general, and a specific drive toward increased torque and power output from race engines, there has been much work done on coating piston skirts to reduce frictional losses. There are various options available, from resin-bonded polymers to DLC. However, other piston coatings can also help us achieve our goals, although by very different means. Piston crown coatings are used for various reasons but, as we shall find out, there are...
There are a number of fasteners that are described as critical in an engine, but if an engineer is asked what these are, he or she will generally give a list of thread fasteners such as con rod bolts or cylinder head studs. Certainly high on any list of critical fasteners though should be piston circlips. Although at times in the past it has been common to use an interference fit to limit the axial movement of the piston pin, modern practice allows the piston pin rotational and axial...
The piston rings used in a race engine are primarily a seal, controlling the flow of oil upwards into the combustion chamber and the flow of blow-by gases into the crankcase. We don't want oil to get into the combustion chamber; in large enough quantities it can cause combustion problems, but even in small quantities where the oil is burned, the loss of oil can be serious, causing us to carry a supply of oil with us. On the road, this isn't a huge problem. In a race though, it means...
Piston pins play a vital, literally pivotal, role in the reciprocating internal combustion engine. Mechanically they are an extremely simple component and, in their most basic form, could be a simple, short length of solid bar. Indeed, many production piston pins are not far removed from this simplest interpretation, being a very plain steel thick-walled cylinder. Racing pins are generally more complex than production car pins, as we wish to reduce mass to an absolute minimum and are less...