What happens if the pushrod length is too short?
This means the pushrod length does not have to be all that precise. Within a certain range, the lifter (aka tappet) will automatically adjust it’s length longer if the pushrod is too short, or shorter if the pushrod is too long.
Is it necessary to have an adjustable pushrod?
Makers of performance parts are simply telling you adjustable pushrods are “required” because that’s probably the easiest way to get the pushrod length right. It’s certainly not the only way, though. Furthermore, it’s not even the best way. At a given weight level, an adjustable pushrod is not as strong or reliable as a non-adjustable.
Can a short pushrod cause excessive valvetrain noise?
So as you can see, there are a whole bunch of common practices that can change your needed pushrod length. If you’ve done any of these things, pushrod length is something you need to pay attention to. Pushrods that are too short for the application will cause excessive valvetrain noise and wear.
Why do I need longer pushrods on my Harley twin?
Smaller than stock base circles are common in high lift cams as a way to alleviate cam box and tappet pin clearance issue. Using longer cylinders, which is common practice when using longer strokes and/or longer than stock connecting rods, can create the need for longer pushrods.
This means the pushrod length does not have to be all that precise. Within a certain range, the lifter (aka tappet) will automatically adjust it’s length longer if the pushrod is too short, or shorter if the pushrod is too long.
Why is the lift ratio of a pushrod important?
The rocker’s lift ratio multiplies the force of the spring as it pushes back against the rocker as the valve closes. The motion and distance traveled on the valve side of the rocker is also more significant than on the lifter and pushrod side.
What’s the best radius for a pushrod tip?
Some builders prefer to use a .210-degree radius tip in higher lift applications, where rocker arm/pushrod interference can be an issue. Because these applications are typically high rpm, high lift, and high spring pressure, Borer says they do not offer .210 radius in the 1010 material or the .083″ wall performance line.
Makers of performance parts are simply telling you adjustable pushrods are “required” because that’s probably the easiest way to get the pushrod length right. It’s certainly not the only way, though. Furthermore, it’s not even the best way. At a given weight level, an adjustable pushrod is not as strong or reliable as a non-adjustable.