How do you adjust valves on nh 220 c1?

To adjust the valves on a New Holland 220 C1 tractor, first ensure the engine is cool and remove the valve cover. Rotate the engine to align the timing marks at Top Dead Center (TDC) on the compression stroke for the cylinder you are adjusting. Use a feeler gauge to check the gap between the rocker arm and the valve stem, adjusting it to the manufacturer’s specified clearance by loosening the lock nut and turning the adjusting screw. Finally, recheck the clearance and reassemble the valve cover.