Crankshaft counterweights are required on certain engine configurations to allow the engine to run without excessive rocking couples; cruciform V8 crankshafts are an example of this. Other engine configurations can run happily without counterweighting of any type to eliminate rocking couples, but they often require some counterweighting in order to maintain bearing loads within reasonable limits. Bearing loads not only have affect engine reliability, but also on friction. Some engineers...
One of the skills of a race driver, indeed any driver, years ago was that of changing gear. Being able to change gear quickly and accurately, taking into account the vehicle speed and the ratio being selected, and doing so time after time without any unruly noise or damage to the gears/dog rings was a skill to be proud of - and not only prevented damage to the gearbox but won races too. Indeed, engineers who regularly stripped and maintained the gearboxes of the great but only two-times...
In this month’s article we will take a look at how engine designers arrive at the number of cylinder head bolts in their engine designs and the compromises they need to make in getting there. Looking at a broad range of engines, not just high-performance race engines, one sees a wide variety in the number of cylinder head bolts in the different designs. Look a little further the reasons for this are obvious. Typically, the number of bolts is a consequence of some other,...
Almost 25 years ago, when World Superbike first started, the machinery was pretty much showroom-standard 750 cc four cylinders and 851 cc twins. When 500 cc Grand Prix bikes had 50% more power than a superbike, 120 bhp was very respectable from an exotic four-stroke 750 cc four-cylinder such as a Yamaha OW-01 or a Honda RC30. The latest World Superbikes are still based on production machinery, but are highly specialised, and much closer to Grand Prix machinery in terms of power and lap...
The entire racing powertrain, from the engine, through the clutch to the transmission, is littered with threaded fasteners. Studs and bolts are responsible for holding together everything from the most mundane unstressed cover plate to the most highly stressed cyclically loaded fasteners such as those found on con rods, crankcase main bearing studs and cylinder head studs. For every bolt there is a corresponding female thread, and for every stud there are two female threads. Greater...