Nissan Repair: valve adjustment, compression stroke, torque specification

Question
could you please give a brief block of instructions for adjusting the valves on a 1990 Nissan 12 valve 2400.

Answer

2400 Hi John -

Here are the basic instructions. I have also included a diagram.

Hope this helps -

Z24i Engine

See Figures 1, 2 and 3

For the intake valves: 1-4-5-8 valve clearance is 0.012 in. (0.30mm). For the exhaust valves: 2-3-6-7 valve clearance is 0.012 in. (0.30mm). The pivot locknut torque specification is 12-16 ft. lbs. (16-22 Nm).

  1. The valves must be adjusted with the engine warm, so start the truck and run the engine until the needle on the temperature gauge reaches the middle setting. After the engine is warm, shut it off.
      
  2. Note the location of any wires and hoses which may interfere with cylinder head cover removal, disconnect them and move them to one side. Remove the bolts holding the cylinder head cover in place and remove the cover. Remember, the engine will be hot, so be careful!
      
With the No. 1 piston at TDC, adjust the top set of valves FIRST; with the No. 4 piston at TDC, adjust the bottom set of valves SECOND

  3. Rotate the crankshaft until the timing marks indicate that the No. 1 piston is at TDC of the compression stroke. If you're not sure of which stroke you're on, remove the No. 1 spark plug and hold your thumb over the hole. Pressure will be felt as the piston starts up on the compression stroke.
      
  4. Check valves (1), (2), (4) and (6) using a flat bladed feeler gauge. The feeler gauge should pass between the valve stem end and the rocker arm screw with a very slight drag. Insert the feeler gauge straight, not at an angle.
      
  5. If the clearance is not within the specified value, loosen the rocker arm lock nut and turn the rocker arm screw to obtain the proper clearance. After correct clearance is obtained, tighten the locknut.
      
  6. Rotate the crankshaft until the timing marks indicate that the No. 4 piston is at TDC of the compression stroke. If you're not sure of which stroke you're on, remove the No. 4 spark plug and hold your thumb over the hole. Pressure will be felt as the piston starts up on the compression stroke.
      
  7. Check valves (3), (5), (7) and (8). Check and adjust valve clearance as necessary.
      
  8. Install the cylinder head cover gasket, the cover itself and any wires or hoses which were removed. Check the engine oil level.