The poppet valve is almost universally used in all forms of transport powered by an internal combustion engine. Motorsport has always had a buoyant two-stroke sector in the motorcycle arena, although this is on the wane now with Grand Prix motorcycle racing having bidden farewell to its last two-stroke class at the end of 2011. So, we have confined ourselves to a four-stroke future, and this generally means poppet valves. Brave attempts by forward-thinking engineers over the generations to try to replace the poppet valve have come to nothing in Read more…
Archive for February, 2012
Aluminium as a valve material?
Thursday, February 9th, 2012Valve springs in the World of Outlaws environment
Thursday, February 9th, 2012
In many areas of motorsport, components are pushed to their limit to squeeze out as much performance as possible. Finding that balance between more performance and too high a risk of failure is something that engine builders are constantly wrestling with.
Ron Shaver of Shaver Engine Specialties, in Torrance, California, builds Tony Stewart’s World of Outlaws 410 cu in sprint engines. And, like many other parts of his Read more…
WSB quick shifters
Thursday, February 9th, 2012
The regulations governing transmissions in the World Superbike Championship require engineers to stick relatively closely to the design of the homologated units, on the production machine. Materials and ratios can be changed but the layout of the main components must remain the same, ruling out the possibility of using systems such as a seamless shift. The addition of quick shifters is allowed, however, and their operation and functionality can be a key factor in a bike’s overall performance. Read more…
Low-pressure carburising
Thursday, February 9th, 2012
The case hardening process, also known as carburising is very old, and pre-dates controlled nitriding processes by some decades; I have seen drawings of racing crankshafts from the 1920s that were hardened by this method. Other race engine parts that are commonly carburised are camshafts, piston pins and gears. The case hardening of highly stressed gears has been the most popular surface hardening process for decades, not only for racing gears but for highly loaded gears in Read more…
Seal material selection
Thursday, February 9th, 2012
Maybe it’s just me but for some reason choosing the most appropriate seal material for an application used to make me uncomfortable. Bamboozled by the plethora of the various product catalogues (for this was before the Internet age) the decision would often be left to the last possible moment, with all the attendant issues it created. I’m sure I wasn’t alone but back then small leaks were often tolerated and, with engine accessibility far easier, could be readily repaired or replaced. In modern, cramped engine compartments though, when Read more…
Feeling the tension
Thursday, February 9th, 2012
It is an undisputed fact that the greatest source of friction in a reciprocating internal combustion engine lies in its ring pack. But the forces necessary to maintain the seal between piston and bore are precisely those that create the parasitic drag, so it is little wonder that engine researchers/designers throughout history have placed an ever-important emphasis in this area. Read more…
The importance of natural frequencies
Thursday, February 9th, 2012
Some of the recent articles concerning pushrod valvetrains have tried to explain the importance of valvetrain stiffness. The advent of the Spintron tester, and its widespread deployment in the r&d shops of engine builders, has given engineers a better insight into valvetrain behaviour, especially the deviation from the ‘theoretical’ valve lift curve we might expect the lifter/pushrod/rocker to impart to the valve. Read more…
Shaver’s winning World of Outlaw pistons
Thursday, February 9th, 2012
Shaver Engine Specialties of Torrance, California, is the official engine builder for Tony Stewart Racing’s World of Outlaws sprint car team. Recently inducted into the Sprint Car Hall of Fame, Ron Shaver has a team of builders dedicated to producing 410 cu in engines for Stewart’s cars, an enterprise that can take as long as 60 hours for a single engine. Read more…
Ford’s 1964 Indianapolis engine
Thursday, February 9th, 2012
In 1963 a Ford-powered Lotus 29 driven by Jim Clark came tantalisingly close to winning the Indianapolis 500, and was prevented from doing so only by the leading roadster of Parnelli Jones dropping oil on the track. The Lotus was running a development of Ford’s Fairlane pushrod V8; drawing pump fuel through carburettors it produced far less power than the competition’s highly tuned Offys running on the more usual Indy brew of Read more…
Liner wear
Thursday, February 9th, 2012
As in all mechanical systems when adjacent parts in contact move relative to each other, wear will inevitably take place. Even in the best designs, lubrication only serves to delay the onset of damage, and failure of one form or another will always occur. The interface between piston/piston ring and the cylinder bore is a perfect example. Read more…
