check the spit valves
Not really enough information given - however - if they are badly out of adjustment you might be referring to the sound of the valves tapping - OR - you are hearing the noise of pre-ignition - perhaps the timing of the engine is off badly.
sounds like your valves are rattling check your oil
Worn piston rings, Burned valves, Sticky valves,
Could be that your valves are out of adjustment or if you have the nonadjustable valves then it could be a build up of carbon on the valves.
you cant if rattling noise occures its a worn lifter very common on 3.1 motors
pressure gradients.
The closure of mitral and tricuspid valves causes the first heart sound. The second heart sound is produced by the closure of semilunar valves (pulmonic and aortic valves).
Bad valves !
By minute electrical singles produced by the heart itself to open and close the valves.
One of the most common reasons for bent valves is a broken timing chain or belt.
when a engine runs too hot it usually warps the heads & causes the valves to stick causing rattling,& it also gets so hot it spreads oil away from components and spalding or pitting occurs; But , there is really no easy fix, it is pretty costly to repair..............