Perhaps the most noticeable trend in lubricant technology over the last 30 years or so is the movement towards lower viscosity oils. The relentless drive for greater efficiency and hence higher power has led to developments where in the past claims of an increase of up to 25kW have been made in a Formula One engine just by changing the oil. Whether you believe this to be true or not is immaterial but research over the years has shown that reducing the viscosity of the oil can lead to friction reduction in the piston ring pack and the bearings. However with its altogether much Read more…

Invariably measured in crankshaft degrees, the duration of any camshaft is generally accepted to be the number of degrees the valve is lifted off its seat to the instant that it shuts again. Ideally it should open instantaneously to its maximum lift and then remain open until it would be closed again equally quickly. This would produce a square shaped valve motion diagram and cause the maximum amount of charge air or exhaust gas to flow. In real life however, the opening and closing are constrained by the laws of physics and valves have to be carefully lifted off their seat, accelerated to maximum Read more…

It always surprises me how often people approach a recognised expert in a particular subject and yet fail to act on their advice. We can all think of occasions when say, consulting a solicitor or lawyer, since theirs is a world of uncertainty and risk, it might be reasonable to seek alternate council. But in seeking advice from a reputable camshaft supplier it seems silly to ignore their advice and go for a completely different cam to that suggested. And yet, I am told, it still happens.

In selecting any new performance camshaft the starting point must surely be the catalogue Read more…

In a good camshaft design the cam profile is but one half of the story. Lifting the valve off its seat and then opening fully before closing it again and dropping it gently back onto its seat requires a lot of careful mathematics and, executed well, should give the maximum valve area opening period for the minimum of forces involved. But just as much as efficient inlet and exhaust cam profiles are critical to any high performance engine, the timing of their opening and closing in relation to each other and in particular to that of the piston motion, can never be overstated. Read more…

So the next generation of British Touring Cars (BTCC) as far as we know at the moment will be 2.0 litre and turbocharged. Starting in 2011, the engines according to the initial press release, will need to be based on 4-cylinder production units and give something like 300 bhp with a 7000 rpm limit and 0.8 bar boost. Running through an inlet restrictor however, for the first time since 1999, camshafts will we were told, be totally unregulated. Way back then there were no restrictions on the cam lift of the 2.0 litre units and engines were delivering something like 320-330 bhp at the stimulated rev limit of 8500 rpm. Read more…

If you were to compare an engine of today with one built, say for instance 50 years ago, no doubt much will have changed. Cylinder head layout, block construction, pistons, rods and cranks have all changed in their various ways. But the one component that is outwardly very similar, having changed very little in that time, is the camshaft. That is not to say there has been little development over the years. Hollow cams, smaller cams, bigger cams, even multiple cams per valve have all been tried and adopted to some extent but when it comes down to it, how many variations of getting a series Read more…

I think it was British Prime Minister Harold Macmillan who is claimed to have first coined the phase, “You’ve never had it so good.” In a speech at a Conservative party rally the phrase referred to the fact that after 15 years of shortages and rationing, the post war economy was now looking rosy again. But for anyone involved in cam design the phrase may be as true in 2009 for him/her, as it was back in 1957 for the people of Britain.

Today, with powerful user-friendly computer software, kinematic cam profile analysis may be readily Read more…

A new concept from the French Surface preparation and coating specialist HEF promises to enhance performance at the cam/tappet interface by altering surface micro-topography. In high pressure applications the lubricant film separating two surfaces can be so thin it is little deeper than surface roughness, even where the components have been super-finished. “Clearly therefore micro-topography of surfaces can have a great influence on performance,” remarks HEF R&D specialist Louis Mourier. He says that HEF has been studying means to

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The heart of any internal combustion gasoline engine just simply has to be the camshaft and the valve mechanism it controls. Designed to maximise the amount of air entering the cylinder at a range of engine speeds, it is often perhaps the first port of call when seeking to improve engine performance. In theory, and in an ideal world, the inlet valve should open to its full lift precisely at piston top dead centre and then close again when the piston next comes to rest at bottom dead centre. Apart from assuming that the intake charge has no inertia this also assumes that the inlet valves themselves

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It is perhaps not widely appreciated that the stand-up comic and a camshaft have much in common. Both rely on split second delivery: the punch line in the case of the former while the latter ensures that the engine valves are opened and closed to a predetermined plan. If the punch line is too early or too late an audience who might otherwise be rolling around in the isles could be on the point of getting up and walking out.

A similar metaphorical disaster could be awaiting the engine. Opening or closing the valves too late or too early could at best lead to a loss in engine performance or at worst,  a catastrophic event with a valve passing through a piston. Read more…