Any technical discussion about engine vibration generally revolves around one of two areas, namely the cranktrain and the valvetrain. In terms of the crankshaft, torsional vibrations - or rather their avoidance or mitigation - are a major concern.
In these days of computer simulation, we can run analyses to study this phenomenon. For many years, however, engineers had to rely on formulae and a lot of painstaking calculations, as laid down in books such as “A Handbook of Torsional Vibration” by Nestorides. These Read more…
In my 
The big-end bearing shells that we find in almost all four-stroke racing engines are an item made with great precision. They are generally ‘graded’ and as such are available in thickness grades which have a range of only a few microns. Moreover, their length is critical in ensuring that the correct pre-load is achieved when fitting. The continuing development of various platings and coatings applied to the bearing shells allow higher pressures than were possible a few years ago.
In last month’s article on connecting rods, I looked at a common way of providing lubrication to the small end of the connecting rod - drilling (or multiple drillings) into the small end of the rod. In many cases this is enough to supply lubrication of the small end. But there are many cases where this might prove inadequate.
The lubrication of the big end of the con rod is generally looked after very well, especially in the four-stroke racing engine as it is normally positively lubricated, i.e. continuously fed by high pressure oil issuing from the oil holes thoughtfully provided by the designer in the crankpin. The lubrication of the small end of the con rod is, by comparison, not so well provided for in terms of lubrication. Owing to the low surface speeds and the oscillating nature of the contact, we cannot expect to provide a continuous hydrodynamic lubrication regime in this
In the case that you don’t have this article delivered to your inbox, I hope that the title has drawn you here either in the hope that you will find how to make your con rods smaller and lighter (in which case you may be disappointed) or because you disagree with the fundamental statement of the title.
In a number of previous articles, I have touched on the subject of residual compressive stress, and how this can be helpful to us in increasing the fatigue strength and hence life of components. This allows them to be smaller and lighter than would otherwise be possible for a given life requirement, and as designers and tuners of racing engines, this naturally appeals to us. Light components, most especially those that rotate are becoming more important than ever to the series production engine designer, as the push for fuel economy continues with haste. Very recently in fact, in 
The big end bearing is critical to the operation and reliability of the four-stroke racing engine. At lower levels of racing, it is possible to run with standard road-going shells of good quality (provided of course that they are rated highly enough to cope with the service loads). After this, special uprated bearings are required. On the RET Monitor website, Anne Proffit has written 
Last month, we looked further into the use of titanium for con rods and this month we look briefly into the use of steel, which remains in many cases the material of choice for con rods. There are far more manufacturers of con rods who offer steel rods than any other material. Titanium is definitely on the increase, and possibly the time will come where steel becomes a ‘minority’ material choice. Some of the reason for steel remaining popular is the price of the raw material – it remains markedly cheaper than titanium. Another important reason is the familiarity of the suppliers with steel con rods. Many have 
This month, we continue to examine material choices. In last month’s article, we looked at some of the reasons why people choose titanium as a con rod material. This month we shall carry on discussing titanium and some more closely allied materials.
