The manufacturer recommends adjusting the valve clearance at the specified interval only if the valve train is making excessive noise. Begin by disconnecting the cable from the negative terminal of the battery. Next, remove the spark plugs and the valve cover. Position the number 1 piston at TDC on the compression stroke, then measure the clearance of the indicated valves with a feeler gauge; when the number 1 piston is at TDC, the valve clearance for the number 1 and number 3 cylinder exhaust valves and the number 1 and number 2 cylinder intake valves can be measured. Record each measurement and compare them with the desired valve clearance, noting which are out of specification for later determination of the required lifter. Turn the crankshaft one complete revolution, realign the timing marks, and measure and record the clearances of the remaining valves; when the number 4 piston is at TDC, the valve clearances for the number 2 and number 4 cylinder exhaust valves and the number 3 and number 4 cylinder intake valves can be measured. These engines do not use valve adjusting shims, so if a clearance is out of specification, the lifter must be replaced with a new lifter that has a different thickness head to correct the clearance, requiring the removal of the camshafts to access the lifters. Mark the lifters to be replaced and record which valve they came from, then measure the thickness of the center of the lifter with a micrometer. To calculate the correct thickness of a replacement lifter that will place the valve clearance within the specified value, use the formula N=T+A-V, where N is the thickness of the new lifter, T is the thickness of the old lifter, A is the valve clearance measured, and V is the desired valve clearance. Select a lifter with a thickness as close as possible to the calculated valve clearance, as lifters are marked on the underside to indicate their size. Mark the new lifters for their destination, lubricate them with engine assembly lube, and install them. After replacing the lifters, install the camshaft(s), and complete the remainder of the installation in reverse order of removal, reconnecting the battery and performing the necessary re-learn procedures.
Posted by NissanPartsDeal Specialist