In order to reduce stress and improve mechanical performance for any highly loaded powertrain component, surface finish is of the utmost performance; a superior surface improves fatigue resistance by removing potential stress raisers and the possibility of crack propagation. For geartrain components this is especially important, requiring high surface hardness to maintain impact strength and resist bending loads on the gear teeth, even though most of the gear material itself must exhibit enough ductility to reduce the risk of brittle failure under shock loading. Furthermore, any Read more…
Archive for March, 2011
DLC in transmission components
Thursday, March 31st, 2011Cryogenic metal treatments
Thursday, March 31st, 2011
There is a vast array of metallic materials of all kinds whose mechanical properties are improved by heat treatment. Steels are commonly raised to high temperatures, quenched and subsequently tempered by raising the temperature to a carefully controlled level and maintained there for a known amount of time; aluminium and titanium alloys are often solution-treated by heating to a given temperature before quenching and age-hardening by heating. In the case of most steels after quenching, the steel is brittle, and tempering softens the material and gives it a level of ductility. Read more…
The monobloc engine
Thursday, March 31st, 2011
Isn’t it strange to think that what we regard today as being ‘obvious’ wasn’t quite so obvious in the early days of race engine design. Take the head gasket, for instance. Today’s young engineers are almost conditioned to think in terms of separate castings for the combustion chamber and valves, and that of the cylinder-supporting structure. But in days gone by, the very idea of having separate components bolted together with apertures where engine coolant, oil and combustion gas crossed must have been totally unthinkable. Read more…
Lifters - flat versus roller
Thursday, March 31st, 2011
In the RET magazine Focus article on pushrod valvetrains (issue 45, March/April 2010), we looked at the effect of flat tappets in limiting the lift velocity of a direct-acting cam on a lifter. The limitation is exactly the same as that in direct-acting overhead camshaft engines. Textbooks on the subject tell us that the distance of the cam-to-lifter contact from the axis of a flat tappet is proportional to the lift velocity of the cam profile. The exact relationship is shown in mathematical form in the RET article. Read more…
Heat transfer
Thursday, March 31st, 2011
With the dominance of four-stroke engines in racing, and the near-monopoly that poppet valves have in such engines, it is little surprise that these parts have become well developed. While most racing is still based on naturally aspirated engines, it is likely that a much greater proportion of race engines in future will be turbocharged, following the continuing trend in series production engines toward smaller boosted power units. There are compelling reasons for doing this; not only is engine efficiency improved, but a small, light engine
Does size matter?
Thursday, March 31st, 2011
How much valve spring does an engine tuner need to propel 8000 hp down a 1000 ft dragstrip? Is it best to use titanium, or is steel sufficient? And are two springs best, or should there be three?
For Bob Vandergriff Jr’s C&J Energy Services National Hot Rod Association Top Fuel dragster, this year competing full-time in the Full Throttle Drag Racing Series of 22 events, the choices are predicated on a change to the set-up configuration for the 2011 season. Read more…
Changing the combination
Thursday, March 31st, 2011
When Bob Vandergriff Jr decided to take his operation full-time in the National Hot Rod Association Full Throttle Drag Racing Series Top Fuel category, he also made the commitment to change his tune-up combination in order to run with the balance of the field more readily.
According to crew member Rob Hauser, “We’re trying to adapt to a newer, more late-model tune-up for 2011 than we used in years past; we’re going with what a lot of the other teams are running.” Read more…
Alternative energy: flywheel batteries
Thursday, March 31st, 2011
The subject of ‘alternative energy’ is soon to be covered in the pages of RET magazine (issue 53), and will cover various technologies aimed at making motor racing more environmentally friendly.
One very topical subject is that of the various hybrid technologies that seek to make our race vehicles more efficient by storing and re-using the kinetic energy normally converted to heat under braking. This is being very actively developed by roadcar manufacturers - for Read more…
The wet sump
Thursday, March 31st, 2011
When it comes to any form of competition engine, I prefer my oil systems to be like my Martinis - dry. But as 99% or more of the engines in the world store their oil immediately below the crankcase, it will come as no surprise that some race regulations insist that this arrangement must be retained. And apart from having to mount the engine a little higher in the chassis and the ever-present issue of oil surge on corners and under braking/acceleration, other problems, sometimes totally unseen, could arise. Let me explain. Read more…
The two-stroke ring
Thursday, March 31st, 2011
Love them or loathe them, and despite being virtually outlawed in international motorcycle racing, two-stroke engines are still the main form of propulsion in the world of karting. With far fewer moving parts and power:weight ratios that most four-stroke engine designers can only dream about, the piston ring in a two-stroke engine has an altogether greater task than those in its four-stroke cousin. Not only does it have to seal the combustion chamber at much higher engine speeds and cope with an increased heat flow (one bang per revolution as opposed to one bang per two Read more…
