forgot to put oil in...

If it was for only 30 seconds you likely didn't do too much damage most the bearings will hold some oil on their surfaces, hopefully you just heard dry knocking and you shut it off fast. Did you damage? Yes Will it make any 'significant' change? Likely, and hopefully not. If now that you've oiled it, and you start it and it keeps knocking...well then I'm sorry... (Always make sure pressure goes up after an oil change.)

its a long shot but id say a wheel bearing

i recommend to fill'er up with about 6 litres of Lucas and hold'er at 5200 rpms for about 4 min. that will help you to get rid of the knock.

you have nothing to lose but to start it up again and see what happens, I would run it at a idle for a bit, if it starts to bog down and labor or doesnt sound good, after a few minutes i would take the oil pan off, pray i could get it off without a tremendous amount of work without pulling the motor and look up at all the connecting rod bearing caps, a dry one with no oil on it will tell you that you spun that bearing. just buy a set of standard main bearings providing this motor has never been overhauled and ut it back together. you probably havent hurt the crank too bad. new pan gasket and bearing should be had for less than a $100 bucks, the learning lesson though is priceless. Alex has a good point, Lucas is good stuff a quart wont hurt, his fix will either make it or break it. - good luck

i had an old car and didnt check the oil level in a while and when i checked it after i heard a little bit of knocking i filled it and it went away i dont think any significant damage was really done :) if it was for a short time it should be fine

i hear you Kelly, things get bad enough without extra help and encouragement, i have personally knocked a hole in a pan after a really fun friday nite and made it home, next day i fired it up and backed up to hear a bunch of nice tapping and shut it right off, i dont think there would of been a pint of oil on the ground where it was parked. i pulled the pan off and welded it up and filled it back up and it was just fine. my worst case was a government motor piece of chevy shit that i jumped the oil sending unit on cause it wouldnt allow the fuel pump to run. it spun a bearing about the time it took to walk to the front of the hood to see the motor sieze and stop. Adam it is a ford and it should be OK

By the way hydraulic lifters will tap pretty good from just sitting a long time, they loose the oil in them but will pump back up and take the push rod clearance up. chances are this it the noise you are hearing. rod knock usually takes some doing and i dont think you ran it enough to spin a bearing in the connecting rod/

probably spun the rod and main bearings, time to rebuild the lower end. if it's the 5.4L you have about 15 seconds of run time before she pops.

just do a normal oil change put oil in new filter let it idle and sit for a lil bit and there ya go and if ya still worry call the ford dealer ask a mechanic there OH and get Luc oil and additive Lucas oil is hwere its at!

So what happened in the end?