Do I really need  to replace my factory pushrods?

Pushrods play a critical role in transferring camshaft profiles to your intake and exhaust valves. Often overlooked during cam swaps and other engine upgrades, pushrods transfer lifter movement to the rocker while enduring pressures in excess of 1000 lbs per square inch. 

In a high-rpm, high horsepower application, the demand on the pushrods is greatly increased. Factory pushrods are relatively weak compared to aftermarket pushrods, and physically can’t handle these added demands. The result is deflection or “bending” of the factory pushrods causing a loss in lift, duration,  and ultimately -horsepower.

So whether you’re replacing your camshaft, upgrading rocker arms, or completely rebuilding your engine, it’s always a good idea to replace your OE pushrods with high quality, aftermarket units. COMP Cams® offers a variety of pushrod designs to suit nearly any application.

Note: Pushrods and rockers wear together much like a cam and lifters. Even though the pushrods may not show any wear, installing new rockers on old pushrods can result in premature failure because of microscopic stress fractures sustained by the pushrod from contact with an “unfamiliar” rocker surface.

Do I need to measure my pushrod length when ordering new pushrods or can I just use the recommended factory length?

We always recommend that you determine the correct pushrod length for your engine before ordering pushrods.  It is important to remember that unless your engine is in the exact  configuration that it left the factory in, the “stock” pushrod length is unlikely to be correct.

There are too many variables that can change the pushrod length that your engine requires, including: engine block deck height, cylinder head deck thickness, camshaft base circle diameter, lifter design, valve stem length, machine work performed, etc. 

COMP Cams® carries Pushrod Length Checking Tools in several different lengths to help you establish correct pushrod length. Once the correct length is determined, you can place an order online at the COMP Cams® Store or direct at 1-800-999-0853.  

What is the most accurate way to measure pushrod length? 

There are two techniques that we recommend for determining accurate pushrod length.  Both techniques are listed below and require the use of COMP Cams® Pushrod Length Checking Tools.  It is important to use one of these tools to ensure that the measurement you take is precise because it directly affects the life and efficiency of your engine’s valve train. 

Technique #1: This first technique uses one of our Hi-Tech™ Pushrod Length Checkers, which adjusts by screwing the two halves of the tool outward. These are marked with the length of the tool with the two halves screwed completely together.
Adjusting the checking pushrod outward one full turn increases its length by .050” –a line that is laser-etched across both halves of the tool will help you keep track of the number of turns you have made.

Note that Hi-Tech™ Pushrod Length Checking Tools are available in both ball-ball, and cup-ball end configurations, which takes the grief and guesswork out of accurately obtaining lengths for cup-end pushrods.

Use the rocker arm geometry verification method to determine how many turns of the tool must be made in order to achieve the correct pushrod length. Multiply the number of turns that were required by .050”, and add the resulting number to the length stamped on the tool, which will tell you what length pushrod you need. For example, a pushrod stamped 7.800 adjusted outward three rotations would be 7.800” + .150” = 7.950”.  

Visit the COMP Cams® web store or your favorite retailer for the Magnum or Hi-Tech™ Pushrod that corresponds to this measurement.

Technique #2: This technique assumes that you have purchased one of our Magnum Pushrod Length Checkers. Once fixed, you don’t need to have an expensive gauge or an extra long caliper to measure it. You need a pushrod of a known length to compare it to (a standard).

Verify your rocker arm geometry, then use a common 6” caliper to measure the difference between the standard and the adjusted pushrod length checker. Add this difference to the length or your standard, and order the pushrod length that corresponds to this measurement.

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