In developing a race engine it is common to evolve valve-lift profiles constantly to improve the ‘breathing’ of the engine. The aim is to increase volumetric efficiency or, more precisely, to increased the trapped mass of fresh, unburned charge. In the case of race engines this often leads to the use of more ‘aggressive’ cam profiles. By ‘aggression’ in the case of valve-lift profiles, this means higher accelerations and the derivative of acceleration with respect to time called ‘jerk’ or ‘pulse’. Put simply, jerk quantifies the gradient of the Read more…
Archive for July, 2011
Stem stiffness and seating
Monday, July 4th, 2011Triple springs for drag boats
Monday, July 4th, 2011
Who could imagine using the same set of valve springs for more than two years in a nitrous-infused 565 cu in V8 engine that competes in the quarter-mile on water?
Wayne Gaskamp has been able to accomplish just that with his 1800-plus hp engine that propels Mike DeClark’s F Bomb drag boat in two categories of National Jet Boat Association (NJBA) competition, the seven-second and unblown fuel jet classes. Read more…
WRC rally transmissions
Monday, July 4th, 2011
With the exception of off-road racers competing in events such as the Dakar Rally, it is unlikely that any type of competition vehicle is required to deal with as varied a range of conditions as a WRC rally car. Ten years or so ago, WRC cars were far removed from any other type of current rally machinery, but with introduction of new rules in 2006 and Super 2000-based regulations in 2011, the complexity of the designs manufacturers can employ has been greatly reduced. Read more…
Nitriding
Monday, July 4th, 2011
There are a great number of components in the race engine that need a hard, wear-resistant surface. Crankshafts, camshafts, cam followers, gears, sprockets, spindles and pump shafts are some example of components that are regularly treated in some way to increase the hardness of the surface. In some cases, there is a requirement that the part has a high level of strength throughout, and such components which are through-hardened. Camshafts, and cam followers are commonly produced in both surface-hardened and Read more…
All screwed up
Monday, July 4th, 2011
As an engineer you must always be looking to improve the product, whether it be to improve its performance, increase reliability or simply make it easier and hopefully cheaper to manufacture. The general term for all this activity is development, and although now a dirty word in any engineering organisation - since it implies that the design wasn’t correct in the first place - the sealing of the combustion gases at the split line between the cylinder liner and fire face has always been the subject of much of this activity. Read more…
Titanium nitride coatings
Monday, July 4th, 2011
The first decade of the 21st century will probably be remembered for when the benefits of surface coating technology really took off in the wider automotive industry. Although it’s something we have known in the performance engine world for a long time, the increased interest will no doubt spur companies into looking for even lower levels of friction and higher levels of durability, all in the name of improved carbon dioxide emissions. Read more…
Rocker stands and shafts
Monday, July 4th, 2011
The pushrod valvetrain, while having great advantages for engine packaging, has the distinct disadvantage of not having a very direct connection between cam and valve, as is the case with overhead cam (OHC) engines. Even in the case where finger followers with roller bearings are used, the stiffness of the system is higher than is typically the case with an overhead valve (pushrod) system. As has been stated in previous RET-Monitor articles on pushrods, efforts are always being made to enhance the stiffness of the components in Read more…
Skirt wear on drag boat pistons
Monday, July 4th, 2011
Wayne Gaskamp, of Long Beach, California, builds drag boat engines for driver Mike DeClark’s National Jet Boat Association (NJBA) boat, F Bomb, which set the records of 7.15 s Elapsed Time at 144.46 mph on the water at Bakersfield, California, in April 2011.
The boat runs in two classes of this series, the seven-second class and the unblown fuel jet class. It’s leading the latter in points after three events and is in second Read more…
Oil coolers - the Laminova
Monday, July 4th, 2011
Engine oil is rather like that famous brand of lager that is said to refresh the parts other beers cannot reach, for in cooling the piston undercrown, valvetrain and bearings it is clearly performing a function in those areas inaccessible to the engine coolant. As in the case of the engine cooling system, this heat eventually has to be distributed into the passing air surrounding the vehicle.
For many years, and where natural flow of air around the Read more…
Chromed rockers
Monday, July 4th, 2011
I can hardly believe it - it’s now almost 50 years since hard rock first came to our ears. That genre of music produced by (often distorted) electric guitars, bass and drums, sometimes accompanied by piano or keyboard, made its mark on the 1960s - much like, in a different sphere of endeavour, the invention of nickel silicon carbide began to influence cylinder bore coatings. Read more…
