The humble rotating shaft seal may be an afterthought for many a designer but its history is certainly never lacking in acronyms! Early lip seals were made using a nitrile rubber. Now referred to, as NBR the application was limited to working temperatures of no more than 90-100 degree C immediately under the lip at the rubbing surface. Changes in seal designs at this stage to use much narrower contact points not only improved its performance, but also reduced the amount of heat generated...
In the inexorable search for reduced weight, the various alloys of aluminium are most commonly used for high performance gasoline engines. Where peak firing loads are higher, for example as in the case of a modern direct injected diesel engine, this may need to be some form of S.G. (spheroidal graphite) iron. With its excellent flow properties in the molten state, sections can be cast much thinner than other cast irons and thus the disadvantage of a density nearer 7 gm/cm3 can, to a...
The surface condition of the cylinder bore has occupied the minds of motorists, engineers and enthusiasts for many years. Often expressed in terms of oil consumption – miles per litre or miles per quart depending upon which side of the Atlantic you reside – provided consumption isn’t excessive, all is generally thought to be fine. In a racing engine however, where cost of ownership is, let’s face it, more or less irrelevant, the real issue here is one of friction. In...
While it might be the aim of many engine designers to minimise the chance of any oil leakage by dispensing with the humble rotating shaft seal, it may not always be possible or even desirable. At any point where there is a mechanical take-off in the form of a rotating shaft, an oil seal will need to be present and while race engine designers try to minimise these occurrences, for the rest of us wishing to improve existing OE equipment or re-engineer old engines, that option simply does not...
If you’ve been in the automotive industry for any length of time you will by now have the words “higher performance, less weight at a cheaper price” more or less burned into the inner soul of your psyche. Since weight is the ultimate destroyer of any performance improvement, it nevertheless rankled if ever we were to reduce the weight of the power unit by some paltry amount someone always managed to find room for yet one more electric motor in the seat! Be that as it may...