LS400 1990-1997

Valve Lash (Clearance) Adjustment

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CAUTION
On models with an air bag, wait at least 90 seconds from the time that the ignition switch is turned to the LOCK position and the battery is disconnected before performing any further work.



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Fig. Adjust these valves FIRST - LS400



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Fig. Adjust these valves SECOND - LS400



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Fig. Valve shim selection chart

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the No. 3 timing belt covers.
  4.  
  5. Disconnect the spark plug wires and remove the cylinder head covers.
  6.  
  7. Turn the crankshaft pulley and align it's groove with the timing mark 0 of the No. 1 timing cover. Check that the timing marks of the camshaft timing pulleys and timing belt rear plates are aligned. If not, turn the crankshaft 1 revolution (360 degrees) and align the mark.
  8.  
  9. Measure the clearance between the valve lash adjuster and the camshaft on the valves in the first sequence and record.
    1. The intake valve clearance cold is 0.006-0.010 in. (0.15-0.25mm).
    2.  
    3. The exhaust valve clearance cold is 0.010-0.014 in. (0.25-0.35mm).
    4.  

  10.  
  11. Turn the crankshaft 1 full revolution (360 degrees) and align the mark.
  12.  
  13. Measure the clearance between the valve lash adjuster and the camshaft on the valves in the second sequence and record.
  14.  
  15. Remove the adjusting shim and turn the crankshaft to position the cam lobe of the camshaft on the adjusting valve upward. Position the hole in the shim toward the outside of the cylinder head. Press down the valve lash adjuster with the proper tool and place the proper tool between the camshaft and the valve lash adjuster. Remove the tool.
  16.  
  17. Remove the adjusting shim with the proper tool.
  18.  
  19. Use the accompanying charts to determine the correct replacement shim. Install the specified valve shim on the valve lash adjuster with the proper tool.
  20.  
  21. Recheck the valve clearance. Install the cylinder head covers.
  22.  
  23. Connect the spark plug wires and install the No. 3 timing belt covers.
  24.  
  25. Connect the negative battery cable.
  26.  

 
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