Well, I've torn apart my engine and replaced just about all of the reciprocating parts in the past few months to get rid of knocking sound I have... all to no avail. After tearing apart the head twice, and completely removing the vtec assembly, I've still the noise. I did finally take a stethoscope to engine and started trying to pinpoint it. Here's what I've got.... there's a sound like a hammer hitting an anvil very faintly all over the block, head, intake, and exhaust manifolds. Its not particularly distinct in any of these areas though. Where it is distinct is right on the fuel injectors (which have the same frequency as the tapping, but are out of phase, except the #4. Its the same amplitude as the others though, so I don't think thats the cause), on the steel bracket that attachs to the water pump and the pump itself(where it is very loud along with the sound of rushing water), on the driver's side engine mount, and the timing belt cover right about even with the tensioner pulley.
I've done tons of speculating but I'm hoping someone else has had this problem before, so I can get a definite answer as to whats about to **** itself. I only real parts around there that move are the oil pump, water pump, the tensioner pulley, and the alternator. The noise sounds almost sounds like a bad bearing, but like I said, I'm not terribly sure. Any help would be much appreciated.