This is a little far fetched.....

There is a very small pin that is the far end of the chain guide post.
that the chain guide rests and rotates on.

If that pin sheared off, the end of that post could be "floating"
and when the chain is stressed it's vibrating against the inner wall of the
chain guide chamber?

I broke one upon reassembly one time when I was torqueing the chain guide post.

Mike

No idea, but I'm thinking now of just driving the car a bit around the block to see if by making the noise I can possibly wear down whatever is interfering or misaligned. If the noise gets better, I keep driving, if worse head back. I'm going to make a WAG though that it's not gonna change. I have a feeling this engine's going to be coming apart...

I checked the oil filter and there was no debris in it, metallic or otherwise.

So, weirdly I have a shaft that will ONLY accept a single row bearing (I measured to be sure), but the cover is definitely dual-row type.

I think that's an extremely bad idea. Noises generally don't go away with positive results.

There is no possibility of a good outcome from this that prevents you from spending less money. Either take the bull by the horns and get it into a qualified mechanic to fix this or you might as well just start throwing money away my friend.

Normally, I would agree with you, but after reviewing some recordings I made of the noise earlier, it does actually seem like the noise is abating somewhat compared to before.

Probably because whatever is making the noise is slowly wearing away..........but that does not mean it is getting better, just that it is wearing away.

I've been working on engines of all types since the age of 8.. Cars, trucks, tractors and jets.

I haven't heard a "good" noise yet. The engine is screaming to you that its hurting. Either you listen to it and do whats required, or it will show you who the boss is.

I vote a screwed up chain guide or tensioner. If you put enough miles on her, the noise is guaranteed to stop. :eek:

BB...
Above has been half a dozen very knowlegable people giving you the same good advice - don't procede without due care & caution. And the advice is for free too.....
Now you may believe you know more than this collective brains trust and you may have plenty of money to burn on your engine, but if I were you I would think long & hard about the possible (probable) outcome of "just driving the car a bit".
It really looks like its time for some professional advice (and that's not being defeatist, just smart looking at the potential outcome). I suspect it will be a lot cheaper than the suck it and see action you are proposing.

i would agree with the above... you'll have to have have some huge huevos and a wallet to match if you are going to push an engine in pain.

this might help you: Pelican Technical Article: Porsche Boxster / 996 Engine Teardown & Disassembly

yep it might mean a partial disassembly, but if you do go that route you may as well make it worthwhile.

So, as you may've seen in another thread, I solved the squealing issue -- it was a loose plug. I wasn't following good diagnostic procedure and wound up spending a lot of unnecessary cash. Always check the small things first!

Thanks to everyone who responded with suggestions. The car is running great now with new clutch / coils / oil / IMSB!

The only thing you can do in these situations is re-trace your steps and whether or not you think the issue is related to what you've done you have to check it anyway. Good job finding it..

Good you found it, and a much less expensive fix than anticipated. The process of elimination works. :)