Isuzu Cars and Trucks 1981-1991

Timing Chain and Sprockets

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REMOVAL AND INSTALLATION
G180Z and G200Z Engine
  1. Disconnect the negative battery cable. Rotate the engine until No. 1 piston is at TDC on the compression stroke.
  2.  
  3. Remove the rocker arm cover, the front cover and the oil pan.
  4.  
  5. Depress or lock the shoe of the automatic chain adjuster in the retracted position.
  6.  
  7. Remove the camshaft sprocket-to-camshaft bolts and the sprocket.
  8.  
  9. Remove the timing chain from the timing sprockets.
  10.  
  11. Using a puller, remove the sprocket and the pinion gear from the crankshaft.
  12.  
  13. Remove the bolt or E-clip and remove the automatic chain adjuster.
  14.  
  15. Inspect the adjuster pin, arm, wedge and rack teeth. Replace assembly if worn. Remove the chain tensioner.
  16.  
  17. Check the timing chain for wear.
  18.  
  19. Check the tensioner pins for wear or damage and replace if necessary.
  20.  
  21. Replace the chain tensioner and adjuster using the E-clips or bolt.
  22.  



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Fig. Timing chain positioning G180Z and G200Z engines



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Fig. Remove the E-clip to remove the adjuster G180Z and G200Z engines



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Fig. Locking the timing chain adjuster G180Z and G200Z engines



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Fig. Aligning the timing chain with the camshaft sprocket G180Z and G200Z engines

To install:

  1. Install the timing sprocket and pinion gear with the groove side toward the front cover. Align the key grooves with the key on the crankshaft, then, drive into position.
  2.  
  3. Confirm the No. 1 piston is at TDC; if not, turn the crankshaft so the key is turned toward the cylinder head side (No. 1 and No. 4 pistons at top dead center).
  4.  
  5. Install the timing chain by aligning the mark plate on the chain with the mark on the crankshaft timing sprocket. The side of the chain with the mark plate is on the front side and the side of the chain with the most links between the mark plates is on the chain guide side.
  6.  
  7. Install the camshaft timing sprocket so the mark side of the sprocket faces forward and so the triangular mark aligns with the chain mark plate.
  8.  


NOTE
Keep the timing chain engaged with the camshaft timing sprocket until the sprocket is installed on the camshaft.

  1. Using a new gasket and sealant, install the front cover assembly.
  2.  
  3. Install the rocker arm cover and oil pan.
  4.  
  5. Refill the cooling system and the crankcase.
  6.  
  7. Connect the negative battery cable.
  8.  

V6 Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Rotate the crankshaft to position the No. 1 cylinder at the TDC of its compression stroke.
  4.  
  5. Remove the front cover.
  6.  
  7. Inspect the sprocket for chipped teeth and wear.
  8.  
  9. Inspect the timing chain for wear; if the chain can be pulled out more than 9.5mm (0.374 in.) from the damper, replace the chain.
  10.  
  11. Remove camshaft sprocket-to-camshaft bolts, the sprocket and the timing chain; if necessary, use a mallet to tap the sprocket from the camshaft.
  12.  
  13. Using a puller tool, press the crankshaft sprocket from the crankshaft.
  14.  

To install:

  1. Using an installation tool and a hammer, drive the crankshaft sprocket onto the crankshaft; make sure the timing mark faces outward.
  2.  
  3. Using Molykote or equivalent, lubricate the camshaft sprocket thrust surface and install the timing chain onto the sprocket.
  4.  
  5. While holding the camshaft sprocket and chain vertically, align the marks on the camshaft and crankshaft sprockets.
  6.  



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Fig. Timing chain alignment marks

  1. Align the camshaft dowel with the camshaft sprocket hole. Install the camshaft sprocket and torque the bolts to 17 ft. lbs. (23 Nm).
  2.  
  3. Lubricate the timing chain with engine oil.
  4.  
  5. Install the front cover and crankshaft pulley.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Start the engine, then, check and/or adjust the timing.
  10.  

 
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