Thanks for the responses on the oil, but, I'm not really focusing on oil as my issue. I posted the synthetic oil discussion I had with him as informational. I'm not out to change anyones mind on synthetic oil, but I just don't think that synthetic oil is the cure for my problem. It may make it better, but if everything was ok, running dino oil would not be the cause of my problem. Therefore, I'd like to get to root cause rather than mask the issue.

So in terms of the noise, would a leaky prechamber cause anything that would make the cylinder noisier or do the adjacent cylinders point to something like a head gasket?

Still haven't been able to find the compression measurements - I'm still looking.

Oh - one more thing, which makes no sense to me. I used a stethescope to try to listen to where the noise is coming from. It really does appear to be doming from the front of the engine. When I listen to the water pump or the timing cover, I hear the metalic noise the loudest. I have run it without the belt, so it can't be the water pump, regardless of it making noise, and I guess it could still be under the timing cover, but it would not stop when removing fuel from one of the injectors (at least I don't think so!)