DML FAQ : Engine : How should I install new roller rockers?
From Chuong Nguyen:
Install all of them and loosen all the allen bolts in the middle.
Do one side of the truck at a time.
Once all the rocker arms are in, adjust them. Slowly start from the front of the motor on back, loosen the nut that holds the rocker arm until you hear a slight tick tick tick tick. Then slowly tighten until the ticking JUST stops. Give her another 1/2 or 1/4 of a turn and tighten the allen nut in the middle in and move on to rocker #2. Continue until done. You might get oil that will splatter over your headers/manifolds, so I guess you could get aluminum foil and make a little shield so it doesn't burn on them, but that's personal preference.
On my 97+ dakota, the valve cover gasket is this reusuable material and doesn't require replacement, so you might not need a new valve cover gasket.
From Sam Parthemer:
Once you get TDC on cyl #1, to find the next TDC, you need to only rotate the engine 45 degrees (you'll see a smaller timing mark on the harmonic balancer). As that approaches, check the next cyl in the firing order (#8) which will close exhaust port. Once the timing marks align you are at TDC on cyl #8. Tighten, then turn engine another 45 degrees (there's another timing mark) you'll be on cyl #4 TDC, tighten, rotate again 45 degrees (you guessed it, another small mark) you'll be on #3, continue #6, #5, #7, and #2. Once you do the first 2 you'll see how easy it is.
Because you may have collapsed a few of the lifters, you'll probably need to do this twice unfortunately. Have it so that the pushrod has just a little friction when you go to spin them - take up the slack for the up/down, then try to spin the push rods between your fingers like a pencil - get a little resistance, tighten down 1/2 turn and lock 'em down. Once you do all of them, you may find that the tapping sound doesn't go away quite as easily. If it doesn't subside, remove both covers, back off all the rockers, and try it one more time (by now the lifters have pumped up, and you can do the install as if fresh from the start-- it will work 100% of the time from this condition).
From Bernd Ratsch:
Remove all the plugs, ground the coil wire, and spin the engine (with the covers off) to pump up the lifters (effectively "priming" the lifters). Then, recheck all the rockers one more time.
This saves a step after the initial startup as it pumps up the lifters and won't excessivly drain the battery while spinning the engine with the plugs removed. Also, warm or hot valve covers aren't fun to remove.