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...
In this and future issues we will look at one of the most critical seals in a race engine, the seal between the top of the cylinder bore and the cylinder head. There are of course many ways of achieving this seal, but perhaps the first question we should ask ourselves is whether or not we need to have a joint which needs sealing in the first place. Race Engine Technology magazine is soon to feature an in depth review of a historic racing engine which did away with this joint by casting the...