How do you adjust hydraulic tappets on engin?

To adjust hydraulic tappets, first ensure the engine is cold and remove the valve cover to access the tappets. Rotate the engine to position the piston of the cylinder you're adjusting at top dead center (TDC) on the compression stroke. Using a feeler gauge, check the clearance between the tappet and the rocker arm; if necessary, adjust the tappet by turning the adjustment screw or nut until the correct clearance is achieved. Finally, recheck the clearance and replace the valve cover.