The vast majority of race engines, and propulsion engines in general, are of the reciprocating type and, for almost all of these, the piston pin is retained by (and has its end-float controlled by) a pair of round wire circlips. The subject of circlip design has been considered in a previous RET Monitor article; however, there are alternatives to the wire circlip which are either in current use or which have been used previously, either for racing or series production. There are two...
Chemical machining is a technique that removes material through the interaction between chemicals and a metallic workpiece. Electrochemical machining (also widely referred to as ECM) offers an alternative to electro-discharge machining (EDM) and is suitable for cutting a variety of materials including very hard alloys. Compared to EDM, there are several practical advantages. The surface finish possible with ECM is typically better than with EDM: ECM can produce mirror-finished parts. EDM...
In a previous RET-Monitor we looked at testing the material properties of composites, so this month we will investigate a machine that is particularly suited to tensile testing of such materials, the video extensometer, which can provide an accurate measurement of deformation and failure while also providing invaluable visual data on the method of failure. Material stress is normally calculated by measuring the specimen’s cross-sectional area and relating this to the measured load...
In previous RET-Monitors we have looked at the construction of racing gearbox casings; however, as regards performance and durability, the materials and manufacturing techniques used for their internals are even more important. Although often housed in very different packages, the gears used in transmissions destined for racing use are essentially the same whether they are for a Formula One car or a WRC racer. Generally, racing transmission manufacturers produce gear sets from high-quality...
In most race engines, much of the heat transfer from the valve to the cooling medium – whether it be oil, water or air – is via the valve seat insert, then into the head and eventually to a fluid that will reject the heat to atmosphere. In the case of the inlet valve, heat flux is only very modest compared to that in an exhaust valve. The inlet valve is kept cool owing to the flow of cool inlet charge over it, and very little heat is rejected to anywhere other than the valve...