Nissan Repair: 2004 Nissan Frontier S/C, cam follower, rod bearings

Question
My engine only has 20,000 miles on it and it recently had a head job because of a serious engine overheating that occurred after an accident.  Now upon cranking the engine I hear a constant light tapping which increases with throttle to the engine.  The engine seems to run great, but I cannot seem to find out what the tapping is.  The tapping appears to be at the bottom of the engine, but it is hard to tell.  Any idea what it could be?  

Thanks in advance for any input.

Chris

Answer
Chris,

The tapping could be a cam follower that needs adjustment.  But, that is on top and under the valve cover.  The other options are an exhaust leak due to the head coming off and being reinstalled.  Could be the gasket on he exhaust manifold.  Other more serious problems could be the rod bearings are worn due to overheating or check for a dented oil pan.  If the bearings were bad the oil pressure would read low.