Lest you think Fig. 1 here is the remnant of some form of horrific engine blow-up, let me explain that what you are looking at is a ductile iron piston ring. Twisted and bent to all manner of shapes the resulting contortion demonstrates vividly how flexible the material can be. Ductile iron comes from a class of materials referred to as SG (spheroidal graphite) irons. Similar in composition to the grey cast-irons used in older type piston ring technology, the carbon flakes in grey...
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. There are various surface...
In the previous article, we looked at the prototype Formula One constantly variable transmission (CVT) system that Williams developed in conjunction with Van Doorn in the early 1990s, and spoke to engineer Arnaud Boulanger who was involved with the project. Anyone who follows Formula One closely will remember the dominant position that Williams had at that time. The CVT's development happened during a golden era for Williams; having the best car, they attracted the best drivers and for...
In the pushrod section of RET-Monitor the reader has been given an insight into the different aspects of pushrod design. Much information has been shared on the specifics of the pushrod concerning its shape, material and contact area of cup and/or bowl. The specifics of the connection between the either hollow or solid centre part of the pushrod has been briefly touched on. In this article the different concepts of connecting the pushrod ends to the centre part are explored further. In...
Esslinger Engineering of South El Monte, California, is primarily in the business of building midget engines based on Ford internals. The company has been in this line of work since 1990. Because its engines are not based on pushrod designs, Dan Esslinger, president, says there are not very many valve-spring issues. "It's just the design of the engine and the design of the camshaft," he says. "Even though we turn a lot of rpms (in the neighborhood of 10,000), we are not...