When it comes to overhead valve engines, one of the largest battles engine builders fight is deflection of the pushrods. So much time and effort are spent to get the camshaft’s specifications right, you absolutely don’t want to lose any of the lift because the pushrod you’re using is yielding like a diving board under the load of opening the valves.
Erson Cams understands the challenges faced by a valvetrain with aggressive cam-lobe ramp rates, big lift numbers, and huge valvespring loads. So, to help combat the inherent deflection that pushrods will experience in those conditions, they have released some thicker-walled variants of their existing pushrod lineup. Minimizing deflection is a function of several variables — not just pushrod diameter — which is why they have focused on supporting big-power applications that don’t call for giant hogs-leg pushrods.
The new pushrods on display at the PRI Show are of the more common 5/16-inch and 3/8-inch-diameter varieties. Made out of seamless aircraft-quality 4130 chromoly steel tubing that is through-hardened and carburized for a hardness of at least 58 Rockwell C. The pushrod ends are centerless-ground, hard-turned 210-degree radius ball ends, and the overall pushrod assemblies are black-oxide coated and held to a maximum runout of only .005 inch. Oh, and they are made entirely in the USA.
These new thicker-wall pushrods come in at .105-inch wall-thickness for the 5/16-inch-diameter pushrods, and .135-inch wall-thickness for the 3/8-inch-diameter pushrods, helping to balance valvetrain stiffness with overall reciprocating weight, allowing you to get the absolute most out of your particular cam and valvetrain combination.