1989-1998 12 Valve Cummins 5.9L Extreme duty 750hp and over
The pushrod is a very important and often overlooked component in any high horsepower build. It doesn't have to do a much, just transmit lift from the lifter to the rocker arm, and bend or deflect as little as possible. Reducing mass in an engine is almost always a good thing however there are a few places, in order to work correctly under high stress, that require a super rigid part. The problem is that more rigidity almost always means more mass. In these applications that require a super rigid part, pushrods, rods, wrist pins etc., to reduce mass would be to get a part that either doesn't live long, or a part that reduces performance. This is where pushrods fall.
There are ways to get a strong part with better design and better materials without gaining mass in some instances. But that mindset too often means one-off designs and exotic materials, and that means a lot of money. In the pushrod world there is a small group of materials that work best for the given mass. Mainly performance pushrods are made from a form of chromoly. Ours are no different being made of 4130 chromoly with hardened 8620 pressed in ends.
A note from Hamilton Cams:
I hear some concern about pushrods and weight, but I can assure you the negatives of additional mass are more than outweighed by the benefits of having the valve open at the correct time, having the valve stay open longer and the additional lift gained from no deflection (bending).
The pushrods in street driven Cummins turning 4500rpm are just a fraction of the weight of cup teams pushrods that spin more than double the rpm's of a Cummins. Race teams spend millions on engine design, and research supports a more rigid design with more mass.
Hamilton pushrods are proudly made in the USA with the highest quality materials available. We have spent many hours designing and comparing with every "performance" diesel pushrod on the market to make sure we have the best. Our pushrods are 3/8” .095” wall on our heavy duty series and 3/8” .095” on the intake and 7/16” .120” or .168” on our exhaust pushrods on our extreme duty sets. If you don’t see what you want, give us a shout. Some of our options include wall thickness, ball and cup sizes, custom lengths, custom tapers, and private labeling.
THE LARGER DIAMETER PUSH ROD IS FOR THE EXHAUST ROCKER/TAPPET.
Part Number: 07-p-002