While pushrods may not have a place in (relatively) unrestricted, top-flight racing engines any more, they are still a part of the racing landscape in many forms of racing, whether by regulation or through financial expediency.NASCAR, of course, mandates the use of a pushrod engine in all its racing series, along with a single block-mounted camshaft and a controlled height above the crankshaft. Like almost every part of a racing engine, pushrod design is the subject of a number of opposing...
If a valve spring for a race engine is to survive a service life of 1400 race miles or 1600 absolute miles then it needs to be robust and reliable. In the Indy Racing League's IZOD IndyCar Series, where the Honda Indy V8 is the sole motive power, Honda Performance Development (HPD) has gone with a steel, flat-top, double-valve spring without insert, to achieve the balance needed on road courses, street circuits, short ovals, speedways and superspeedways. HPD has tried different designs...
In the previous article on this subject we looked at the use of Inconel as a valve material. This month I'll look at an application of another high-temperature valve material, Nimonic alloys.These are nickel-based alloys which, similar to Inconel materials, maintain a high proportion of their room-temperature strengths at elevated temperatures. As with Inconel alloys they are commonly used in turbocharged or supercharged applications, where the high operatingtemperatures in these...