If we look at sectioned drawings of some old piston engines, we might be able to count many more piston rings being used per piston than we would find these days. We might see multiple rings placed above the piston pin (as we would find now) but these might also be augmented by one or more rings below the piston pin, placed towards the bottom of the piston skirt. Cylinder sealing was much worse in years gone by – oil leakage past the rings was very bad, and rates of blow-by of...
Phosphate coatings have been covered in a couple of previous surface treatment articles. In the first of these articles, we looked mainly at engine applications, including piston rings, camshafts and so on. In the second article, we looked in slightly more depth at some of the advantages and disadvantages of phosphating. The design engineer or metallurgist who recommends this type of coating needs to be aware of the potential problems with hydrogen embrittlement of high-strength steels...
Accurate measurement and testing of parts with complex internal features can be fraught with difficulties. Often, the only way to achieve accurate checking is to sacrifice a part to destructive testing in order to ensure correct internal tolerances are being met. However, even this cannot ensure complete control over the quality of finished parts. For example, the make-up of parts produced using SLS (selective laser sintering) processes can vary from one component to the next, so a means...
The transmissions used in Formula One do not require the use of a clutch during gear changes, and as such, drivers only use a clutch during the start of the race and when leaving a pit stop. Despite this infrequent use, they are still an important contributor to a car’s performance, not least because a poor start can ruin a race result. Carbon-carbon clutches have been the norm in Formula One since the mid-1980s, providing high levels of bite and heat resistance coupled with low...
Valve collets (also known as valve keepers, valve cotters or valve locks) are not something that engine tuners often turn to in order to make their engines perform better or improve reliability. While collets for the general automotive market are very price-sensitive, decisions on the quality of racing collets are not driven purely by the desire to save, say, 0.1 cents per piece. So, where collets for passenger cars are stamped from sheet steel or wire, many of those produced for racing...