Is there an adjuster on a performance pushrod?
None of the parts know or care if there’s a adjuster somewhere on the pushrod to change it’s length with. 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.
How does height of cylinder head affect pushrod length?
Changing the height of the cylinder head changes height of the rocker arm relative to the cam, and therefore it needs to be factored into the needed pushrod length. In particular, it’s very common to “deck” a head to raise compression in a high performance motor.
Can you change the length of a stock pushrod?
If your motor is all stock, the answer is no. Your stock pushrods are designed to be within the acceptable length range even in the worst case tolerance stack-up situation. Changing the height of the cylinder head changes height of the rocker arm relative to the cam, and therefore it needs to be factored into the needed pushrod length.
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.
When do you need an adjustable pushrod on a Harley twin?
When you need to set your lash or your lifter plunger preload precisely, as is done for solid lifters or travel limited hydraulic lifters, an adjustable pushrod is the only reasonable way to accomplish it.
Do you need adjustable pushrods on a hydraulic lifter?
Since the self-adjusting hydraulic lifter is by far the most common, we’ll cover it first. The most common method for getting the pushrod length right after any of the aforementioned changes is to use adjustable pushrods. In fact, it’s so common that you’ll see some performance parts labeled “Adjustable Pushrods Required”.