how to determine pushrod length, 351W, nonadjustable valves, rollercam, hydraulic lifters
Okay, nukkleheads, here's an often repeated question. There is a lot of wrong information out there, so let's see if we can get it right in one go so future readers get the right information.
Setup: 1996 351W 5.8L. Stock everything, rollercam, roller hydraulic lifters, stock rockers (non roller).
Trying to find: pushrod length.
Own: pushrod length measure device.
why am I dinking with it: valve train noisy
Details: I've read that for non-adjustable rockers, the only two ways you can adjust - well - anything - is by changing pushrod length, the lifter's height, and shimming or shaving the rocker pedestals. I have no intention of doing anything to the pedestals, or the lifter heights, so that leaves the pushrods. The valve train as it stands is NOISY, and I've determined I have oil coming to the lifters, and they're pumped up. That only leaves the pushrod lengths as culprits.
I've seen a lot of videos out there describing "preload", "lash", etc, but most of these videos have to do with adjustable rockers. I don't know what the right procedure is to determine the pushrod length for a non-adjustable rocker. I am thinking it's RELATED to how it's done for adjustable rockers, but not the same. In other words, get lifter onto the base of the cam lobe, then start tightening the rocker's non-adjustable bolt until the slack goes out of the pushrod, then figure out how much further you have to tighten the bolt until it snugs up and reaches torque range. This is assuming the lifters are either all the way pumped up, or you're watching them *very* closely to make sure they're not depressed into their bores. Obviously, if there is too MUCH slack, when the bolt is all the way tight, the pushrods are too short. If they're too long, and the lifters are pumped up, the valve won't close all the way.
Currently, I can turn the bolt about 1/4 to 1/2 full turn before it reaches torque snugness.