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    GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

    Adjustment

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    1.9L GASOLINE AND 2.2L DIESEL ENGINES



    See Figure 1

    The valves are adjusted with the engine Cold.

    1. Remove the rocker arm cover. For details, please refer to Engine & Engine Overhaul of this guide.
    2.  
    3. Verify that the rocker arm shaft nuts/bolts are properly torqued to 16 ft. lbs. (22 Nm).
    4.  
    5. Using a wrench on the damper pulley bolt or using a remote starter button, turn the crankshaft until the No. 1 piston is at TDC of the compression stroke. You will know when the No. 1 piston is on it's compression stroke because both the intake and exhaust valves will remain closed as the crankshaft damper mark approaches the timing scale.
    6.  

    Another method to tell when the piston is coming up on the compression stroke is by removing the spark plug and placing your thumb over the hole, you will feel the air being forced out of the spark plug hole. Stop turning the crankshaft when the TDC timing mark on the crankshaft pulley is directly aligned with the timing mark pointer or the zero mark on the scale.

    1. With the No. 1 piston at TDC of the compression stroke, perform the following valve setting procedures:
      1. If working on the 1.9L engine, use a 0.006 in. (0.152mm) feeler gauge, to set intake valves of cylinders No. 1 & 2. Using a 0.010 in. (0.254mm) feeler gauge, set the exhaust valves of cylinders No. 1 & 3.
      2.  
      3. If working on the 2.2L engine, use a 0.016 in. (0.40mm) feeler gauge, to set the intake valves of cylinders No. 1, 2 & 3, then set the exhaust valve of cylinder No. 1.When adjusting the valve clearance, loosen the locknut with an open-end wrench, then turn the adjuster screw with a screwdriver and retighten the locknut. The proper thickness feeler gauge should pass between the camshaft and the rocker with a slight drag when the clearance is correct.
      4.  

    2.  
    3. Rotate the engine one complete revolution, so that cylinder No. 4 is on the TDC of its compression stroke and the timing marks are aligned. This time the No. 4 cylinder valves remain closed as the timing mark approaches the scale.
    4.  



    Click image to see an enlarged view

    Fig. Fig. 1: Valve adjustment using a feeler gauge

    1. With cylinder No. 4 on the TDC of the compression stroke, perform the following valve setting procedures:
      1. If working on the 1.9L engine, use a 0.006 in. (0.152mm) feeler gauge, to set intake valves of cylinders No. 3 & 4. Using a 0.010 in. (0.254mm) feeler gauge, set the exhaust valves of cylinders No. 2 & 4.
      2.  
      3. If working on the 2.2L engine, use a 0.016 in. (0.40mm) feeler gauge, to set the intake valve of cylinder No. 4, then the exhaust valves of cylinders No. 2, 3 & 4.
      4.  

    2.  

    2.0L AND 2.8L ENGINES



    See Figure 2

    These engines utilize hydraulic valve lifters which means that a valve adjustment is NOT a regular maintenance item. The valves must only be adjusted if the rockers arms have been disturbed for any reason such as cylinder head, camshaft, pushrod or lifter removal.

    1. Remove the air cleaner and the rocker arm cover(s). For details, please refer to Engine & Engine Overhaul of this repair guide.
    2.  
    3. Rotate the crankshaft until the mark on the crankshaft pulley aligns with the 0 mark on the timing plate. Make sure that the No. 1 cylinder is positioned on the compression stroke. You will know when the No. 1 piston is on it's compression stroke because both the intake and exhaust valves will remain closed as the crankshaft damper mark approaches the timing scale.
    4.  

    Another method to tell when the piston is coming up on the compression stroke is by removing the spark plug and placing your thumb over the hole, you will feel the air being forced out of the spark plug hole. Stop turning the crankshaft when the TDC timing mark on the crankshaft pulley is directly aligned with the timing mark pointer or the zero mark on the scale.

    1. With the engine in the No. 1 firing position, perform the following adjustments:
      1. If working on the 2.0L engine, adjust the intake valves of cylinders No. 1 & 2 and the exhaust valves of cylinders No. 1 & 3.
      2.  
      3. If working on the 2.8L engine, adjust the intake valves of cylinders No. 1, 5 & 6 and the exhaust valves of cylinders No. 1, 2 & 3.
      4.  

    2.  
    3. To adjust the valves, back-out the adjusting nut until lash can be felt at the push rod, then turn the nut until all of the lash is removed.
    4.  

    To determine if all of the lash is removed, turn the push rod with your fingers until the movement is removed.

    1. When all of the lash has been removed, turn the adjuster an additional 1 1 / 2 turns; this will center the lifter plunger.
    2.  



    Click image to see an enlarged view

    Fig. Fig. 2: When adjusting valves on engines equipped with hydraulic lifters, turn the pushrod between your thumb and forefinger in order to determine lash

    1. Rotate the crankshaft one complete revolution and realign the timing marks; the engine is now positioned on the No. 4 firing position. This time the No. 4 cylinder valves remain closed as the timing mark approaches the scale.
    2.  
    3. With the engine in the No. 4 firing position, perform the following procedures:
      1. If working on the 2.0L engine, adjust the intake valves of cylinders No. 3 & 4 and the exhaust valves of cylinders No. 2 & 4.
      2.  
      3. If working on the 2.8L engine, adjust the intake valves of cylinders No. 2, 3 & 4 and the exhaust valves of cylinders No. 4, 5 & 6.
      4.  

    4.  
    5. Once the valves are properly set, install the remaining components.
    6.  

    2.5L ENGINE



    Because the rocker arm fasteners are secured and torqued, valve lash is NOT adjustable on the 2.5L engine. If a valve train problem is suspected, check that the rocker arm bolts are tightened to 22 ft. lbs. (30 Nm). Be sure to only tighten the rocker arm bolts when the hydraulic lifter for that rocker arm is on the base circle of the camshaft and NOT when it is held upward on the lobe. When valve lash falls out of specification (valve tap is heard), replace the rocker arm, pushrod and hydraulic lifter on the offending cylinder.

    4.3L (VIN Z) ENGINE



    See Figure 2

    This engine utilizes hydraulic valve lifters which means that a valve adjustment is NOT a regular maintenance item. The valves must only be adjusted if the rockers arms have been disturbed for any reason such as cylinder head, camshaft, pushrod or lifter removal.

    On 1993 models, the 4.3L (VIN Z) engine may be equipped with either of two rocker arm retaining systems. If your engine utilizes screw-in type rocker arm studs with positive stop shoulders, no valve lash adjustment is necessary or possible. If so equipped, please refer to the 4.3L (VIN W) valve lash information, found later in this section. If however, your engine utilizes the pressed-in rocker arm studs, use the following procedure to tighten the rocker arm nuts and properly center the pushrod on the hydraulic lifter:

    1. To prepare the engine for valve adjustment, rotate the crankshaft until the mark on the damper pulley aligns with the 0° mark on the timing plate and the No. 1 cylinder is on the compression stroke. You will know when the No. 1 piston is on it's compression stroke because both the intake and exhaust valves will remain closed as the crankshaft damper mark approaches the timing scale.
    2.  

    Another method to tell when the piston is coming up on the compression stroke is by removing the spark plug and placing your thumb over the hole, you will feel the air being forced out of the spark plug hole. Stop turning the crankshaft when the TDC timing mark on the crankshaft pulley is directly aligned with the timing mark pointer or the zero mark on the scale.

    1. With the engine on the compression stroke, adjust the exhaust valves of cylinders No. 1, 5 & 6 and the intake valves of cylinders No. 1, 2 & 3 by performing the following procedures:
      1. Back out the adjusting nut until lash can be felt at the pushrod.
      2.  
      3. While rotating the pushrod, turn the adjusting nut inward until all of the lash is removed.
      4.  
      5. When the play has disappeared, turn the adjusting nut inward 1 additional turn.
      6.  

    2.  
    3. Rotate the crankshaft one complete revolution and align the mark on the damper pulley with the 0° mark on the timing plate; the engine is now positioned on the No. 4 firing position. This time the No. 4 cylinder valves remain closed as the timing mark approaches the scale. Adjust the exhaust valves of cylinders No. 2, 3 & 4 and the intake valves of cylinders No. 4, 5 & 6, by performing the following procedures:
      1. Back out the adjusting nut until lash can be felt at the pushrod.
      2.  
      3. While rotating the pushrod, turn the adjusting nut inward until all of the lash is removed.
      4.  
      5. When the play has disappeared, turn the adjusting nut inward one additional turn.
      6.  

    4.  
    5. Install the remaining components, then start the engine and check for oil leaks.
    6.  

    4.3L (VIN W) Engine

    The 4.3L (VIN W) engine and some of the 4.3L (VIN Z) engines are equipped with screw-in type rocker arm studs with positive stop shoulders. Because the shoulders allow the rocker arms to be torqued into proper position, no adjustments are necessary or possible. If a valve train problem is suspected, check that the rocker arm nuts are tightened to 20 ft. lbs. (27 Nm). When valve lash falls out of specification (valve tap is heard), replace the rocker arm, pushrod and hydraulic lifter on the offending cylinder.

     
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