To locate noise, I use an old timers trick, a broom stick. Noise travels better in dense material so if you touch the wood to lets say the water pump and you hear ... while pressing the other end of the broom stick against your head. I know this sounds strange but it works.
Try listening to the back end of the motor. There is a flex plate (automatic trany. I do not know if manual has this) and if one or more of the six mounting bolts have loosened, they will hit the bell housing and make a 'tic-tic' that is = to the RPM.
Valve train noise is 1/2 RPM.
So get a broom handle, poke around and avoid the moving parts!
Good luck and post the results.