While swapping the engine from the 04 to the 03 I took advantage of the opportunity to do the headgaskets and oil pump. The engine ran fine previously but while I had the lifters out most of them fell over and drained of oil. Fast forward to tonight and I filled the oil filter with oil and tried cranking the engine with no fuel pump fuse or relay to build oil pressure. Probably 4 bursts of 10-15 seconds each but the oil pressure light never went out. I pulled the pressure switch and all was dry so I threw caution to the wind and replaced the fuel pump relay and fuse.

After about 3 seconds of cranking it started but the engine sounded horrible, like a coffee can full of marbles, so I shut it down within a second or two. I removed the drive belt (there's no coolant in the vehicle anyway) and tried starting it again to ensure it wasn't something outside the engine, but it still sounded awful. I did this once or twice more but immediately shut it off due to the sound. At first I feared the oil pump gears weren't doing their thing (new gears, vaseline, original timing cover) and maybe that was the noise, but it sounded more like coming from the top of the engine. I pulled the oil pressure switch and a bunch of oil came out so I felt a little better. I gulped and started it a 4th (or 5th) time and to my relief the oil pressure light went out within 2-3 seconds but I shut it down again immediately because it still sounded pretty bad.

Could the awful racket be dry lifters? I have only run the engine a total of maybe 10 seconds in total, should I be just letting it run to see if the sounds gets better (or goes away). Before I do that I want to confirm the possibility that maybe this is to be expected given the empty lifters. I have no experience with hydraulic lifters but noticed (after the fact) that the RAVE says to keep them upright. Anyone been here before? Naturally I'm afraid of damaging anything but maybe I'm just wussing out?

 

To avoid any lifter noise, I dropped all of mine into a cup of oil and let them sit overnight, then I took an available free pushrod and manually pressed with it to make several clicks on each lifter (while each was still submerged in oil). This insured that each one filled up with oil.

No lifter noise on its first start after my rebuild!

 

Ouch, that was a good idea. Had not occurred to me. Live and learn. Next time...

ARGH

Edit, well in the absence of any better advice I started the truck this morning and let it idle. In 10-15 seconds the lifter noise quieted to a small tick, and with 60 seconds the engine sounded smooth as I could hope for once again. For anyone finding this thread, excruciating lifter noise will go away once the oil refills them.