Mitsubishi Pick-ups and Montero 1983-1995 Repair Guide

VALVE LASH

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Models that are equipped with hydraulic lash adjusters require no adjustment. The best way to maintain hydraulic adjusters is through regular oil and filter changes.

Valve lash must be adjusted on all engines not equipped with hydraulic (oil-filled) automatic lash adjusters. Some engines are also equipped with an additional set of small valves called jet valves which require adjustment. These valves require special adjustment procedures which are addressed later in this section.

ADJUSTMENT



2.3L Diesel Engine

See Figure 1

The valve clearance (hot engine) for intake and exhaust valves is 0.010 in. (0.25mm). Check and or adjust the valve clearance about every 16,000 miles (24,000 km)-refer to the Maintenance Interval chart.

  1. Run engine until normal operating condition is reached.
  2.  
  3. Stop engine and turn off the ignition.
  4.  
  5. Rotate the engine until piston in No. 1 cylinder is at Top Dead Center (TDC) on the compression stroke. To do this, use a wrench or socket on the crankshaft pulley to rotate the engine in a clockwise direction until the timing mark on the crankshaft pulley or crankshaft vibrational damper lines up with the timing tab on the front of the engine block.
    1. Remove the rocker arm cover to gain access to the intake and exhaust valves.
    2.  
    3. Observe the No. 1 cylinder valve springs. If either of the two valve springs is compressed, or either of the two valve springs is at a different height from the other one, then the No. 1 cylinder is not on its compression stroke. If this is the case, rotate the engine one more crankshaft revolution until the timing marks once again line up.
    4.  

  6.  



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Fig. Fig. 1: The correct sequence for adjusting the valve clearances-2.3L diesel engine

  1. Loosen the locknuts on the intake and exhaust valves of cylinder No. 1, the intake valve of cylinder No. 2 and the exhaust valve of cylinder No. 3 (labelled A in diagram).
  2.  
  3. Adjust the clearances to 0.010 in. (0.25 mm) with a feeler gauge. Retighten the locknuts.
  4.  
  5. Use the same method previously described to rotate the engine until the No. 4 piston is at TDC on its compression stroke.
  6.  
  7. Loosen the locknuts on the intake and exhaust valves of cylinder No. 4, the intake valve of cylinder No. 3 and the exhaust valve of cylinder No. 2.
  8.  
  9. Adjust the clearances to 0.010 in. (0.25 mm) with a feeler gauge. Retighten the locknuts.
  10.  
  11. Reinstall the rocker arm cover.
  12.  
  13. Check idle speed and readjust if necessary. Check for any leaks from around the rocker arm gasket.
  14.  

2.0L and 2.6L Engines

These engines are equipped with jet valves and hydraulic lash adjusters. The lash adjusters eliminate the need for periodic intake and exhaust valve adjustments.

  1. The first step is to warm the engine to operating temperature. Since the engine will cool as you work, it's best to actually drive the vehicle at least several miles in order to heat the internal parts to maximum temperatures. Drive some distance after the temperature gauge has stabilized. Then, stop the vehicle, turn off the engine, and block the wheels.
  2.  
  3. Remove the rocker arm cover as described in Engine & Engine Rebuilding .
  4.  
  5. Recheck the torque for the cylinder head assembly bolts. Observe the sequence in the appropriate illustration (see Engine & Engine Rebuilding ).
  6.  
  7. Rotate the engine until piston No. 1 cylinder is on the compression stroke at Top Dead Center (TDC). To do this, use a wrench or socket on the crankshaft pulley to rotate the engine in a clockwise direction until the timing mark on the crankshaft pulley or crankshaft vibrational damper lines up with the timing tab on the front of the engine block.
    1. Observe the No. 1 cylinder valve springs. If either of the two valve springs is compressed, or either of the two valve springs is at a different height from the other one, then the No. 1 cylinder is not on its compression stroke. If this is the case, rotate the engine one more crankshaft revolution until the timing marks once again line up.
    2.  

  8.  
  9. Loosen the jet valve locknut and back off on the adjusting screw a small amount. Insert a 0.10 in. (2.5 mm) feeler gauge between the rocker and the end of the jet valve stem. Check the clearance by moving the feeler gauge in and out. A slight drag should be felt. If the clearance is not as specified, turn the adjusting screw either in or out until the clearance is correct. Hold the screw to prevent it from moving and tighten the locknut. Check the clearance again to make sure it didn't change when the locknut was tightened.
  10.  
  11. Depending on what cylinder you started with, bring the next cylinder in the firing order to TDC and repeat the adjustment procedure as described in Steps 5 and 6. Repeat this procedure until all the valves are adjusted.
  12.  
  13. Install the rocker arm cover using a new gasket as required.
  14.  
  15. Check the timing and idle speed and adjust as necessary. Check for any leaks.
  16.  

2.4L, 3.0L and 3.5L Engines

The newer 2.4L, 3.0L and 3.5L engines are not equipped with jet valves, thus, because of hydraulic lash adjusters, do not have any valves that require periodic adjustment. The only time the valves on these engines would have to be adjusted is in the case of reassembly after dismantling the engine head. For this procedure refer to Engine & Engine Rebuilding .

 
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