Additional information that may be useful to other Explorer owners with this issue, in no particular order...
- The radiator doesn't have to be removed. In fact, I discourage it, since the radiator, trans cooler and AC condenser are inexplicably married in a most unholy union. A standard harmonic balancer puller will not fit with the radiator in the truck, but a shorter bolt from Orchard Supply Hardware in the center of the puller provided a good workaround. For the puller I had, it was a 5/8" fine thread (18 per inch, I think; Home Depot only had coarse thread 5/8" bolts). You will need to provide some sort of spacer between the end of the bolt and the crankshaft snout, so that the bolt doesn't chew up the crank (maybe a socket from that cheap auto parts store tool set you bought in a pinch that one time...).
- I had posted in another thread that I was having trouble getting the power steering pump off. Instructions I found elsewhere said it had to be unbolted from the engine (and one set of instructions even stated it had to be completely drained and removed). It simply needs to be unbolted (but all bolts need to be removed, as the bracket for the PS reservoir blocks access to one of the front cover bolts). The issue with mine is one of the bolts, attaching it to the front cover, is hidden behind a PS line on the pump. The pump has four mounting holes, and several sets of instructions I saw for Mustangs and other vehicles say only three of them need to be used. I believe this bolt was placed incorrectly at the factory and should have been in the rear hole instead of the front. I cut it off with a Dremel and a cutoff wheel between the pump and the front cover, and will add one to the rear hole soon. (You do also have to pull the pulley, because even with the pump unbolted, it won't move out of the way enough to get to the front cover bolt behind it. When I did the head gaskets on my Expedition, I had enough room to pull it out of the way.)
If you suspect your motor has jumped time due to chain slack, the next two points will NOT apply to you. Mine didn't, so I was able to use this procedure successfully. I've used this procedure on a 5.4 and a 4.6 with good results.
- Cam timing: it's not necessary to get the camshaft holding tool that Ford specifies (or the crank holding tool, for that matter). Before removing the chains, set up the engine as follows: The dot on the crank sprockets should be at a 6:00 position (this puts the keyway on the crank at what would be about a 10:30 position for the hour hand). The cam sprockets should have their dots at about an 11:00 position on the passenger side and 12:30 position on the driver side. From there, the tensioners can be removed. Note that one or both of the cams might rotate a bit after the timing chain tension is released. Not a big deal, if the motor is set up right before releasing them. You'll fix that on installation...
- Timing chain/tensioner install: This is a minimum two person job, if you don't have the holding tools. Rely on the copper-colored links on the chains, but mark them with something to make them more obvious (I used a Sharpie). Place one of the colored links on the crank sprocket, at the dot at 6:00. Then route the chain through the tensioner and guide arms, and start to place it over the cam sprocket, placing the other colored link at the dot on the cam sprocket. You may find you have to rotate the cam a bit to get it to sit right (using a ratchet and 18mm socket), and also hold the chain on the bottom of the crank sprocket. Once the links are in the right spot, you can release the hold on the tensioner, and the cam if you had to rotate it. Repeat for the passenger side.
- Find all the debris you can. I had it in all sorts of places in the front cover and the front of the engine. I didn't find anything in the pan, but didn't drop it, either. The guides seem to initially break into large pieces, but the meat grinder environment turns them into little pieces pretty quickly.
- Ford changed the design of the tensioner assembly sometime after 1998. Before, you could collapse it in a vise, and insert a paper clip in a hole to hold it (my Expedition and Ranger both worked this way). Now that hole is gone, and a retaining clip is used. I got lucky in that I had to get one new tensioner, so I used the retaining clip from it on both tensioners. If your tensioners are good, you'll need to find that retaining clip or come up with another method to collapse the tensioners. Auto parts stores didn't know what I was talking about when I asked about it, and my local Ford dealer doesn't carry any of the Ford-specified "special" tools.
- While you're in there, modify the little drip guard for the oil filter if you haven't already, so it doesn't eat up the wiring harness that sits right above it. Three 13mm bolts and five minutes, and about 3/4" off the top and that's it.