Thanks for the ideas. It's been a while since I tore into one of these.
Tom: I've got everything out except the crank: Spinning by hand, no noise. Then add the cam & gear (no lifters) with the 2 plate screws snug: Spin by hand, thump thump thump just like when it's running
CNC: Pistons show very little wear, about .003-.004 piston-to-wall, skirts ok, no noise from crank, cam thrust is very tight (maybe even TOO tight, the plate doesnt rotate as smoothly as I'd like to feel). So I'm convinced its the cam or cam gear setup, only noise I can find.
The cam IS worn, some lifters concave, 4 wouldnt even come out (had to pull em from the bottom then file a ridge off the edge). I've seen & run worse cams though. One pushrod wasnt spinning so I pulled that rocker & pushrod, but the same noise while running. It just doesnt SOUND like lifter noise.
I had something similar once on a big Ford, turned out to be a high spot on the damper "ticking" against the timing tab. REALLY sounded internal, disgusting it was something that simple. That's why I stripped this one all the way down til I found a possible culprit.
I'll try to post a movie.
Sure, I could re-do it all but at this point this is a matter of PRINCIPLE, I'm determined to find this noise & fix it for free. This engine was supposed to be a free project (gaskets only) & now I'm obsessed with that. Hope you get the idea - just determined to find it!
Ok here it is on You Tube. I know it almost sounds like a loose bolt or the spinner wrench rattling but it's not. This gear is aluminum, are the fiber gears quieter or less prone to this noise? Then again my 292 has an aluminum gear and no such noise:
