In the recent Race Engine Technology article on valves, there was some discussion of the merits of hollow valves, and indeed the subject has been covered by Anne Proffit and I in these Monitor articles in the past.
We should briefly restate here the reasons for hollow valves. The first and more obvious reason is mass reduction in cases where a reduction in stem axial stiffness does not compromise the proper action of the valve or present problems through lack of bending Read more…
Containing a valvetrain that works with a four-cylinder, heavily boosted engine that develops more than 1000 hp should be a difficult enterprise, but Time Attack factory Scion (Toyota) team WORLD Racing is having no problems with its steel coil valve springs.
Time Attack, which is a form of American road racing where the car-driver tandem compete for a time slip is “a bit of road racing with a bit of a drag racing element to Read more…
There are often lots of shiny parts in a race engine, and some companies produce parts of a high surface finish as a sales point; there is a perception by some that a polished part is better quality and therefore has an inherently higher value.
There are very good reasons though why some parts benefit from having a high level of surface finish. One only has to look at the data presented in engineering textbooks on the subject of fatigue strength and cyclic Read more…
Historically, the rear main bearing oil seal has always been a challenge for the engine designer. Ask any modern competitor of a classic or vintage racecar when apart from getting the engine started in the first place, the second most important quest is to keep the oil where it belongs - in the sump and not on the garage floor!
Hidden out of sight somewhere between the rearmost Read more…
If you think sealing the gap between the piston and cylinder bore of a conventional reciprocating engine presents something of a challenge, then spare a thought for the problems facing the Wankel engine. Once heralded as the rightful successor to the humble piston engine, the rotary Wankel unit gave a smoother power delivery in a more compact form, but early examples suffered greatly from combustion gas sealing issues between the rotor and its housing. And if you examine the dynamics of it all, you begin to see why. Read more…
Rockers are a critical element in the valvetrain of any overhead-cam engine, and so we should not be surprised to find that their development continues to be the subject of much activity in racing circles. Much of the racing in the US, for example - including the incredibly popular NASCAR categories and their various ‘feeder’ series - is based on engines using the overhead-cam (pushrod) valvetrain.
In recent years, NASCAR has allowed the various Read more…
In Time Attack, a popular form of road racing in the US, the objective is not to compete wheel-to-wheel but rather to set down the fastest lap possible. According to Rob Cardona, manager of WORLD Racing, Toyota’s Scion brand official team, “It has a bit of road racing with a bit of a drag-racing element to it, going for a time slip without racing each other.”
While cars in any particular class will be on the track at Read more…
In the world of automotive engineering there is a strong belief that unreliability creeps in when humans interfere. Take servicing the engine oil system, for instance.
Consisting of a pump, a filter, some bearings and one or two other components - not forgetting, of course, the oil - when assembled under the cleanest of conditions and serviced regularly to the same standards, we can expect the engine to last for the full design life (generally at least 150,000 miles, or 240,000 km) and Read more…
In this article I want to emphasise the non-material side of the cylinder head, focussing on cooling. Whereas in previous articles I have provided some insight into cylinder head structure and coolant flow, this time I will look at cooling mechanisms in the cylinder head.
The unceasing demand for higher specific power has enforced higher operating temperatures on engine parts, in particular cylinder heads, which has a significant effect on thermo-mechanical loading and consequently Read more…
It could be that I’m giving the wrong impression here but on a cold winter’s evening there is nothing I like so much as a small glass of whisky. Settling into my favourite armchair alongside the dying embers of a log fire and savouring the delights to come, I watch carefully as the dash of tepid water (not too much now!) is added to the tumbler and then slowly mixes. That it does so is one of life’s extraordinary things, as the surplus electrons of the water’s oxygen atoms are attracted to the electron-deficient hydrogen atoms of the alcohol, strangely Read more…
