Last month, we started to look at materials which are being used for con rods. The article looked at the use of aluminium, which finds widespread use in drag-racing. This month we shall turn our attention to engines with less than 5000 hp and con rods in another low-density material: titanium. Titanium has long been used as a con rod material for racing, and its benefits have been slowly taken up by road car and motorcycle manufacturers in the last couple of decades, although this has only...
In the previous article, we looked at the hardening and tempering of crankshafts. This month we shall look at the final and probably most important stage of heat-treatment, namely that of surface treatments, especially nitride hardening, more commonly known as ‘nitriding’. Nitriding is essentially a surface treatment, and its effect extends to a finite distance below the surface of the component. Before we start, we should note that nitriding, whilst overwhelmingly popular for...
For those of you who have ever grappled with the art of carburettor ‘tuning’, the invention of the fuel injector must have come as something of a huge relief. The selection of choke sizes, main jets, emulsion tubes and air correction jets was all a bit fraught at times but once mastered and coupled with accelerator jets and something called ‘progression’, would seem to have guaranteed a job for life. Or so we thought. While the theory was always well understood it was...
Isn’t it strange how solving one issue in racing can sometimes lead to solving a different problem in production engines many years later. The evolution of the main bearing cap springs to mind. It was while examining a cylinder block prior to rebuilding a classic engine that made me reflect on how far, in terms of technology modern road vehicle engines have come. The crankcase in question was a five bearing four cylinder unit of 1970s origin and having a relatively undersquare...
It is a fact not appreciated by many, except the specialists, but the technology of the cylinder bore surface finish has changed significantly over the years. While oil consumption was perhaps the greatest driver in the past, the push to achieve even less and less exhaust emission at higher and higher mileages, has caused OE engine manufacturers to focus even greater resources into getting the surface finish of the cylinder bore exactly right. And while, to the OEM this means emissions...