The lubrication of the big end of the con rod is generally looked after very well, especially in the four-stroke racing engine as it is normally positively lubricated, i.e. continuously fed by high pressure oil issuing from the oil holes thoughtfully provided by the designer in the crankpin. The lubrication of the small end of the con rod is, by comparison, not so well provided for in terms of lubrication. Owing to the low surface speeds and the oscillating nature of the contact, we cannot...
In a previous article discussing the oil holes which are necessary in crankshafts, the author briefly discussed one of the methods by which oil is transferred to the crankpins for the purpose of lubricating the big end of the con rod and its bearings. The article discussed how the oil, having arrived at the main bearing, must make its way through the crankshaft via the oil drillings to the crankpin. We touched briefly on compound-angle drillings and axial drillings in that article, but...
Simply mention the words 'engine knock' to any aftermarket EMS supplier and I almost guarantee that the conversation will cease albeit perhaps only briefly. But safe to reiterate that 'knock' or more precisely detonation, should be avoided at all costs and that the engine should be mapped sufficiently away from these borderline conditions, the conversation will no doubt continue along the original lines. And in truth for the vast majority of race units, particularly naturally...
Ever since the dawn of mass manufacturing, engineers have been preoccupied with shape and position but it is only in comparatively recent times that this has been formalised into a geometrical standard. The language of geometric dimensioning and tolerancing, GD&T to you and me, consisting of rules, symbols and conventions, was designed to ensure parts could be made anywhere in the world and put together with the highest confidence to produce a fully functional product or assembly....
With a greater emphasis on waste and recycling in our private lives, is it no wonder that the ethos is now beginning to spill over into the world of competition. While once engine component parts might have been discarded in favour of new replacements, today, where possible, they may be reclaimed to race another day. No better example of this is the re-plating of aluminium motorcycle engine barrels; particularly those that tend to suffer most distress - those of two-stroke engines. The...