get large screw driver and place it over the left engine mount and handle to ur ear, if it louder round the mount then look at pump bearing might be causing the noise, place the screw driver again over the rocker cover if it less noise in that area it helps to pin point the noise, i thought mine was a loose bolt or somthing like that but might be worth the listen, or ask a mate to help u, my pump took under 1 hr to complete but new timing belt would be adivsed, so allow 2 hrs in total if the noise u discribe is coming from mount area.