If you ever change your heads, camshaft, or you're just upgrading your valve train, you will need to readjust the rocker arm / valve / push rod setup. Unfortunately, this is not a simple bolt down and go item. Take your time, watch what you're doing, and you shouldn't have any click clacking when you're done. The following procedure is for adjusting stud mounted roller rockers with hydraulic lifters. You will need to have the valve covers removed and a method of rotating the crank clockwise by hand. During the procedure, work on one intake/exhaust set (cylinder) at a time. In this example, we'll use the number 1 cylinder located at the front of the engine on the passenger side. The very first roller rocker is sitting on the intake valve and the second roller rocker is resting on the exhaust valve. (How can you tell? Look at the exhaust header and the location of the header tube in relation to the valve location. They will typically line up with each other on the 5L Ford engine).
The idea is to set the pre-load and tighten the roller rocker while the lifter is resting on the camshafts base circle or heel. This ensures that both the intake and exhaust valves are closed while you're trying to set the pre-load.
To start, rotate the engine in it's normal clockwise rotation by hand
and watch the intake and exhaust valves on the number one cylinder. As the exhaust valve just begins to open, stop rotating the engine and focus on the intake roller rocker on that same cylinder. If the push rod was snug against the lifter, loosen the intake roller rocker and allow the lifter to return to its normal position.
To get the proper pre-load, begin tightening the intake roller rocker
while moving the push rod up and down with your fingers. Ensure that the push rod is seated properly in the lifter and roller rocker cup. Once the up and down play is gone, start feeling for a slight resistance while turning the push rod with your fingers. It won't be much beyond that point. I like to move the push rod up and down at first because oil on the parts will hide a bit of the turning resistance. This point in slight resistance is called "Zero Lash".
Your intake roller rocker is now ready to be tightened at its final
setting. For a street driven vehicle, tighten the adjusting nut 1/2 - 3/4 of one full turn further than your zero lash point and lock the adjuster into position. For a race application, it's suggested to run the setting slightly loose at 1/8 - 1/4 turn past zero lash.
Now that your intake valve is adjusted properly, it's time to adjust the exhaust valve on that cylinder.
Rotate the engine clockwise again and watch the intake roller rocker that you just adjusted. The intake
valve will open and then close. When the intake valve is just shy of being closed, adjust the exhaust valve for cylinder number 1. Use the same procedure listed above to obtain the proper zero lash, and tighten the roller rocker adjusting nut according to your application.
The intake and exhaust valves are now properly adjusted for cylinder number 1. Follow the same
procedure on each of the remaining intake/exhaust sets (cylinders).
Although this should be done as one of the first steps, make sure your push rods are the proper
length. Consider taking a mirror and/or feeler gauge, and check under the roller rocker arm to ensure proper clearance between the roller rocker and the top of the valve spring retainer.
On a side note:
If you are installing new lifters, it's not necessary to soak the lifters in oil prior to the install as long as
you prime the engine with oil prior to start up (according to Crane Cams). However, I usually dip / coat them in oil on the install.
There is a hole on the side of the lifter. It doesn't make a difference which direction it faces.