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
Archive for July, 2009
Micro texturing camshaft surfaces
Monday, July 13th, 2009The sting is in the beehive
Sunday, July 12th, 2009
Donn Rickard was designing valve springs even before 1981, when he started R/D Valve Springs in Hesperia, California. A veteran of the racing game, Rickard is responsible for design work and farms out his actual manufacturing to Performance Springs, Inc. in Michigan, known throughout the industry by their acronym, PSI.
“In the late 1990s I helped design the current racing valve spring and it really hasn’t changed much over the years. It is still made of an alloy silicon chrome with vanadium added to the mixture,” Rickard told me.
The modern racing car gearbox
Sunday, July 12th, 2009
It can be sobering to sit back and consider what we ask of a racing car gearbox when we require it to perform a structural role as well as functioning as a change speed box…
Generally the loads that we will ask it to absorb are a significant proportion of, or even a multiple of all up vehicle weight, and they will act in a variety of directions and combinations.
Cavitation Shotless Peening
Sunday, July 12th, 2009
Most people in the high performance world recoil when they hear a reference to cavitation. Cavitation, the formation of vapour bubbles in a flowing liquid, is usually the prelude to component failure, particularly
with propellers, impellers, pumps, and all forms of hydraulic machinery. In some cases, even cylinder heads have been known to fail from this phenomenon. Cavitation occurs when the pressure of a liquid stream falls below its vapour pressure. As bubbles form and then collapse rapidly, intensely destructive shock waves can be produced
Form in place
Sunday, July 12th, 2009
Form-in-place gasket technology is becoming widely available.
Every time an engine builder has to lay a silicon bead on a head gasket, he finds himself muttering, “There has to be a better way to do this!”, as he wipes the goo off his fingers. Excess silicone sealant inevitably squeezes out at the joint, creating a freestanding bead of material that is held in place solely by a very thin film at the seal joint, creating the perfect opportunity for it to fatigue off
The Lord of Rings
Sunday, July 12th, 2009
Of all the components in a race engine, the top or compression ring has probably the hardest task. Although its primary purpose is to seal the combustion chamber from the crankcase below, this role is somewhat complicated by the requirement to dissipate the vast majority of the heat in the piston and to do so under the most trying of dynamic conditions. Positioned as close as possible to the top of the piston crown as is technically feasible, it is suggested that as much as 80% of the heat in the top of the piston, is conducted through this ring and into the cylinder wall.
Its all in the tip
Sunday, July 12th, 2009
According to Dr Andy Randolph, engine technical director at NASCAR championship contenders Earnhardt Childress Racing, the interesting period for pushrod development was a couple of years ago. “Many teams were looking into alternative materials for a stiffer, yet lighter solution, compared to the traditional chrome moly steel” that had been in use for many years.
Dr Randolph notes that the exotic materials solutions produced some beneficial effects, but to his mind, the cost-to-benefit trade-off just did not make the grade.
Top Gear
Sunday, July 12th, 2009
Few of us give our oil pump a second’s thought. So long as that big red light on the dashboard keeps going out at the required time and doesn’t flash too much when the engine is hot and idling, then all would seem to be well. But the poor old engine designer, when setting out at the initial design stage, has much to think about. To begin with, he realises his engine will need lubricating oil flow to the main and big end bearing assemblies. Notice the word flow and not pressure. The oil pressure is required mainly to overcome the centrifugal action of the oil in the crankshaft feeding the big-end bearings.
Piston progress
Sunday, July 12th, 2009
It has taken about two to three years of trial and error, but one American manufacturer believes they have found a new family of aluminium metal matrix materials for use in piston manufacturing. Rather than the customary silicon carbide matrix, a material that has a tendency to wear out manufacturing tools and has extremely sharp edges, this exclusive material consists of spheroidal aluminium oxide AI203 particles, randomly distributed as its reinforcement.
Keeping the faith
Sunday, July 12th, 2009
You can’t talk about cylinder liners for very long without referring to the terms of either ‘wet’ or ‘dry.’ Although fairly self-explanatory, these refer to liners, which are either in direct contact with the engine coolant or those which are not. And at one time, and more years ago than I care to remember, these terms may also have referred to a certain type of Tory politician. In those recessionary times (yes, we had them back then as well!) monetary policy was the political mantra and you either believed in it or not. Likewise with cylinder liners, you are either a firm believer in wet liners or you are not.
