Chrysler RAM50/D50/Arrow 1979-1993 Repair Guide

Valve Lash

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GENERAL INFORMATION



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.

ADJUSTMENT



2.0L Engine

See Figures 1 through 6

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

The cylinder head bolts should be retightened before attempting this adjustment.



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Fig. Fig. 1: View of the auto-lash adjuster



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Fig. Fig. 2: Rotate the crankshaft clockwise until the No. 1 cylinder is as TDC-2.0L engine shown



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Fig. Fig. 3: Jet valve clearance adjustment



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Fig. Fig. 4: Measure the No. 1 and 2 jet valves indicated by the arrows



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Fig. Fig. 5: Loosen the locknut and adjust the clearance using a feeler gauge and turning the adjusting screw



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Fig. Fig. 6: Measure the No. 3 and 4 jet valves indicated by the arrows

  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 air cleaner assembly.
  4.  
  5. Remove all of the spark plugs from the cylinder head to make the job a little easier.
  6.  
  7. Remvo the front upper timing cover.
  8.  
  9. Remove the rocker arm cover as described in Engine And Engine Overhaul .
  10.  
  11. Recheck the torque for the cylinder head assembly bolts. Observe the sequence in the appropriate illustration (see Engine And Engine Overhaul ).
  12.  
  13. 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 vibration damper lines up with the timing tab on the front of the engine block.
  14.  

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.

  1. Measure the jet valve clearance at the location of the arrows indicated in the illustration. Standard value on a warm engine should be 0.0098 in. (0.25mm).
  2.  
  3. If the clearance is not within specifications, 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.
  4.  
  5. Rotate the crankshaft 360° so the No. 4 cylinder is at TDC.
  6.  
  7. Measure the jet valve gap at the location indicated by the arrows in the illustration. Standard value on a warm engine should be 0.0098 in. (0.25mm).
  8.  
  9. 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 previous steps. Repeat this procedure until all the valves are adjusted.
  10.  
  11. Install the rocker arm cover using a new gasket as required.
  12.  
  13. Install the air cleaner and spark plugs.
  14.  
  15. Check the timing and idle speed and adjust as necessary. Check for any leaks.
  16.  

2.3L. Diesel Engine See Figure 7

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 vibration 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. 7: 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 (labeled 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.  

2.6L Engine See Figures 8 through 12

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



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Fig. Fig. 8: Align the cut-out in the crankshaft pulley with the timing mark



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Fig. Fig. 9: Next, check whether or not the alignment mark on the camshaft sprocket is at the position shown-2.6L engine shown



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Fig. Fig. 10: Measure the jet valve clearance at the locations indicated by the arrows

The cylinder head bolts should be retightened before attempting this adjustment.

  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 air cleaner assembly.
  4.  
  5. Remove all of the spark plugs from the cylinder head to make the job a little easier.
  6.  
  7. Remove the front upper timing cover.
  8.  
  9. Remove the rocker arm cover as described in Engine And Engine Overhaul .
  10.  



Click image to see an enlarged view

Fig. Fig. 11: Hold the screw and loosen the locknut



Click image to see an enlarged view

Fig. Fig. 12: Insert a feeler gauge and turn the screw to adjust the clearance

  1. Recheck the torque for the cylinder head assembly bolts. Observe the sequence in the appropriate illustration (see Engine And Engine Overhaul ).
  2.  
  3. 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 T mark lines up with the timing tab on the front of the timing cover. Next check whether or not the alignment mark on the camshaft sprocket is at the position shown in the illustration.
  4.  

If the alignment mark on the camshaft sprocket is off by 180°, position the No. 4 cylinder at TDC.

  1. Measure the jet valve clearance at the location of the arrows indicated in the illustration. Standard value on a warm engine should be 0.0098 in. (0.25mm).
  2.  
  3. If the clearance is not within specifications, 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.
  4.  
  5. Rotate the crankshaft 360° in the clockwise direction, and align the cutout in the pulley with the T mark on the timing chain cover.
  6.  
  7. Measure the remaining valve and, if not within specifications, adjust as necessary.
  8.  
  9. Install the rocker arm cover using a new gasket as required.
  10.  
  11. Install the air cleaner and spark plugs.
  12.  
  13. Install the spark plugs.
  14.  
  15. Check the timing and idle speed and adjust as necessary. Check for any leaks.
  16.  

2.4L and 3.0L Engines

The 2.4L and 3.0L engines are equipped with hydraulic lash adjusters. They do not have any jet 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 And Engine Overhaul .

 
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