Small Engines (Lawn Mowers, etc.): knocking in briggs and stratton 13.5 eng, briggs and stratton, main bearing

Question
i was wondering what would cause the engine to knock,I took it apart and could not find anything other than the governor was worn and the camshaft scored. I replaced both pieces and it still knocks and now it sound like it may be out of time, any help would be appreciated.Engine no is 21b707,model no0453e1 and code is 060417za

Answer
A few things come to mind.  Is the connecting rod journals out of spec?  Are the upper or lower main bushings out of spec?  The crankshaft journals?  Is the rod torqued?  Is the rod installed upside down?  Is the cylinder, piston wore out?

Valve Clearance, both valves .004-.006
Rod Torque 150 inch pounds
Crank reject sizes
      Mag Jounral 1.356"
      Crankpin Journal 1.497"
      PTO Journal 1.693"
Main Bearing Reject
      Mag use tool 19219
      PTO 1.629"
Cylinder Bore 3.4365
             3.4375
For the timing, did you line up the crank and cam marks?  Is the flywheel key sheared?  I have had keys shear after rebuilding the engine.
Let me know if this helps.
Eric