Your shopping cart is empty.
Product Qty Amount


Pushrod stiffness

[email protected]
The pushrod, or overhead valve (OHV), engine has a lot to recommend it in terms of packaging, although it achieves this at the expense of much valvetrain stiffness compared to an overhead cam (OHC) mechanism. One of the least stiff members in the pushrod valvetrain is the pushrod itself. Owing mainly to space constraints, but also possibly to mass targets in a smaller regard, the pushrod is a long slender component whose stiffness can dominate the dynamic behaviour of the whole valvetrain...

Double-spring valve springs for success

[email protected]
John Force Racing (JFR) is one of the most successful Funny Car teams in the history of the NHRA Full Throttle Drag Racing Series. Understanding that multiple team cars on the track results in successfully shared technology, JFR this year is competing with three drivers - John Force, Robert Hight and Mike Neff. There would have been four, but daughter Ashley Force Hood is taking the year away from competition to give birth to her first child. Neff, the crew chief who helped Gary Scelzi to...

Valve-stem texturing - snake oil or snake skin?

[email protected]

The matter of ensuring that valve-stem lubrication is sufficient has two main benefits. First, any friction between stem and guide creates energy that is necessarily subtracted from crankshaft output power and converted to heat. Minimising this is clearly a desirable aim. Second, if the lubrication is sufficient, we minimise the rate of wear of the valve guide and valve. There are a number of surface treatments that aim to reduce friction and make the stem less susceptible to wear, and...