For those of you with a high boredom threshold, a constantly recurring theme in my articles for RET-Monitor and Race Engine Technology is to stress the importance of compressive residual stresses at the surface of components which are cyclically stressed. The compressive stress is extremely effective in improving the fatigue strength of engine components, and there are a number of ways of achieving this; some of these have been discussed before in RET-Monitor. Read more…

RF85 was covered last year in the pages of the May 2009 Race Engine Technology, but in that instance most of the data presented referred to the results of tests on cutting tools such as saw blades and taps.

I spoke recently to the owner of Better Than New, in Tennessee, US, the company which carries out the RF85 surface treatment and which claims to reduce dry friction between metal pairs by around 85% (hence the name RF85).

Read more…

Aluminium offers many benefits to mechanical engineering designers, and racing engine designers have long been keen to exploit its low density and good strength. There are now aluminium alloys commercially available with tensile strengths well above 700 MPa (>100 ksi) and the development of alloys for specific properties has accelerated in recent years.

One disadvantage with aluminium, however, is its propensity to oxidise - anyone who has left their Read more…

In the last article on the subject of surface finish, we looked at some of the important reasons for providing a good level of surface finish. On surfaces involved in sliding contact we can help to ensure that the lubricant film maintained by the basic geometry of the components and their motion is thick enough to keep the high-points or asperities of the two surfaces apart by providing a smoother surface with less peaks, and also peaks which are of a lower height. We also noted that the basic endurance limit of a material is increased Read more…

When we specify or design components for a racing engine, quite often we are interested in the surface finish. It is an important aspect of the overall perceived quality of the component, and it can have a large influence on the performance of the part in question for a number of reasons, of which there are three main ones to consider, namely endurance, wear and friction.

In terms of endurance, we know from reading Race Engine Technology, other magazines, Read more…

In racing we rely much more on machined components than our counterparts in the arena of series production engine design - we need to make parts quickly, we need the flexibility to make swift design changes and we want to take advantage of the improved mechanical and fatigue properties that high quality wrought materials offer us compared to castings etc. Whilst we all want to save money, especially in these straitened times of financial recession, we have less financial constraints than companies who have to produce hundreds of thousands of the same Read more…

In a previous article on the subject of surface treatments, RET Monitor contributor Tom Sharp discussed various surface hardening methods for crankshafts, and the method of nitriding was expanded upon in a subsequent article on the subject of nitride hardening. Not only does nitriding of steels offer a more wear-resistant surface, but there are substantial benefits from the introduction of compressive residual stresses with regard to fatigue behaviour.

Literature is littered with accounts of similar benefits Read more…

The use of amplified light has a great many applications in industry and beyond. Many of us reading this will do so having had our sight improved by laser eye treatment. In terms of the use of lasers in engineering, perhaps the most widespread application is laser-cutting, allowing sheet metal to be cut into any shape from a simple dxf drawing file. Many engineering works specialising in sheet metal will offer laser cutting nowadays. In a similar way, lasers are often used for part-marking purposes, from part and serial numbers to barcodes etc. Read more…

Last month we looked into induction hardening of crankshafts and the inherent differences between that process and nitriding.

We saw that induction hardening carries significant potential benefits; the main one being that the crankshaft is only heated locally which means that distortion can be effectively managed.

There is also no maximum limit on case depth with Read more…

Race engine crankshafts are typically produced from steel billets and are gas nitrided to improve fatigue life and reduce wear.

However nitriding is not suitable for all crankshafts, as the author found recently whilst detailing a crankshaft from a 70-year old historic Grand Prix racing engine. The crankshaft in question ran with rolling element main and crankpin bearings, in which the actual rollers ran directly on the journal surfaces of the crankshaft. Read more…