Do you know if the inner cam bearing is stock?

You've got an oil pump that seems to be acting wonky and a motor making whining noises. That sounds like a problem that's in the cam chest somewhere to me.

If you're reasonably certain that the cam bearing has never been replaced, I'd just get in there and do it now. Once you've got the cam chest opened up, you can get a good look around and see if you can find something going on with the oil pump.