When engaged in building Dodge Mopar engines for use in USAC’s National Midget series, Bob Wirth of Hayward, California relies on pushrods from Smith Bros of Bend, Oregon. He works with the raised port (RP) head and relates, “The RP cylinder head layout is really hard on parts. The intake rocker is offset 3/4-inch and that exacerbates the stress at the adjuster and at the end of the pushrod, because you’ve got a rocking couple across the span of the rocker. This ‘ball...
There are valvetrain tricks to making good power and obtaining durability and longevity from a Dodge Mopar USAC National Midget engine, according to engine builder Bob Wirth of Hayward, California. “We need them all.” The biggest problem with midget racing – like Pro Stock drag racing – is that the rate of acceleration of the engine can be exceptionally high, above 2000-3000 rpm per second. The valve spring must be able to control the mass of the valvetrain through...
Last month, we looked at the application of hollow valves, and noted, as had Anne Proffit’s recent article, that titanium is a popular choice for these components. Many engineers who specify hollow valves do so for reasons of mass reduction and improved valve control; hence titanium is a natural choice in this respect.Titanium has very low density compared to the more traditional poppet-valve materials and so is the kind of material that we look to when trying to minimise mass as part...
The article on Advanced Metals last month looked at some of the aluminium materials which are being used and investigated currently in Formula One. This month we shall begin to look at some of the applications of titanium alloys, again at which materials are currently being used, and what might be over the horizon. The main applications for titanium in racing engines currently are connecting rods, valves and fasteners. Indeed, there are a number of production engines where titanium is now...
RET recently attended the 2009 UK Formula Student competition at the Silverstone circuit in Northamptonshire. Of the total 87 teams from 16 countries, seven were in Class 1A, of which four were from the UK. Class 1A is the competition’s low carbon category. Teams are encouraged to use green technology and alternative fuels to reduce their CO2 emissions. In an additional challenge, the teams calculate the CO2 and energy that are used during manufacture of the car. Teams compete in all...