Chevrolet Chevette/1000 1976-1988 Repair Guide

Timing Belt and Sprockets

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REMOVAL & INSTALLATION



Gasoline Engine


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Fig. Fig. 1Exploded view of the timing belt and related components



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Fig. Fig. 2Camshaft alignment and timing belt tension check



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Fig. Fig. 3Timing belt adjustment specifications


CAUTION
Do not discharge the air conditioner compressor or disconnect any air conditioning lines. Damage to the air conditioning system or personal injury could result.

A belt tension gauge is necessary for the completion of this procedure.

  1. Rotate the engine so the timing mark on the camshaft pulley is at 0 degrees, #1 cylinder is at Top Dead Center. With #1 cylinder at TDC, a 1 / 8 " drill rod may be inserted through a hole in the timing belt upper rear cover into a hole in the camshaft drive sprocket. This is provided to verify camshaft timing and to facilitate installation of the belt.
  2.  
  3. Remove the timing belt lower cover.
  4.  
  5. Loosen the idler pulley retaining bolt and allow the idler to rotate clockwise.
  6.  
  7. Remove the timing belt from the camshaft and crankshaft sprockets.
  8.  
  9. Remove the distributor cap and mark the location of the rotor at #1 cylinder firing position. For vehicles equipped with air conditioning, remove the air conditioning compressor and the lower compressor bracket. DO NOT disconnect any lines!
  10.  
  11. Remove the timing belt sprocket bolt and washer.
  12.  
  13. Remove camshaft sprocket.
  14.  
  15. Remove crankshaft sprocket.
  16.  

To install:

  1. Place crankshaft sprocket on end of crankshaft. Be sure that the locating tabs face outward.
  2.  
  3. Align the dowel in the camshaft sprocket with the locating hole in the end of the camshaft.
  4.  
  5. Apply Locktite® sealer or equivalent to the threads of the bolt and install bolt and washer. Torque to 100 Nm (75 ft. lbs.).
  6.  
  7. Install belt on camshaft and crankshaft sprockets.
  8.  
  9. Using a 1 / 4 " allen wrench, rotate the idler pulley counterclockwise on its attaching bolt until all slack is taken out of the belt. Tighten the bolt.
  10.  
  11. To facilitate the installation of the timing belt, #1 cylinder should be at TDC. If necessary, rotate the crankshaft clockwise a minimum of one revolution. Stop when #1 cylinder reaches TDC. DO NOT reverse direction.
  12.  
  13. Install a belt tension gauge between the camshaft sprocket and the idler pulley on the slack side (see illustration).
  14.  
  15. Adjust to the proper tension by loosening the idler attaching bolt. Using the 1 / 4 " allen wrench, rotate the idler pulley until the proper tension is attained. Torque the attaching bolt to 20 Nm (15 ft. lbs.).
  16.  
  17. Install the timing belt lower cover and front cover.
  18.  
  19. Replace the distributor cap.
  20.  
  21. For vehicles with air conditioning, replace the lower compressor bracket and the air conditioning compressor.
  22.  
  23. Attach the negative battery cable.
  24.  

Diesel Engine


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Fig. Fig. 4Injector gear setting mark location for diesel engines



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Fig. Fig. 5Camshaft fixing plate for diesel engines



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Fig. Fig. 6View of the timing belt holder



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Fig. Fig. 7Tension spring location



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Fig. Fig. 8Timing belt component installation sequence for diesel engines



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Fig. Fig. 9Tighten the tension pulley bolts in sequence, top first, bottom second



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Fig. Fig. 10Final tightening sequence for the tension pulley and plate bolts

In order to complete this procedure you will need three special tools. A gear puller (J-22888), a fixing plate (J-29761), and a belt tension gauge (J-26486).

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the fan shroud, cooling fan and the pulley.
  2.  
  3. Disconnect the bypass hose and then remove the upper half of the front cover.
  4.  
  5. With the No. 1 piston at TDC of the compression stroke, make sure that the notch mark on the injection pump gear is aligned with the index marks on the front plate. If so, thread a lockbolt (8mmX1.25) through the gear and into the front plate.
  6.  
  7. Remove the cylinder head cover and install a fixing plate (J-29761) in the slot at the rear of the cam. This will prevent the cam from rotating during the procedure.
  8.  
  9. Remove the crankshaft damper pulley and check to make sure that the No. 1 piston is still at TDC.
  10.  
  11. Remove the lower half of the front cover and then remove the timing belt holder from the bottom of the front plate.
  12.  
  13. Remove the tension spring behind the front plate, next to the injection pump.
  14.  
  15. Loosen the tension pulley and slide the timing belt off the pulleys.
  16.  
  17. Remove the camshaft gear retaining bolt, install a gear puller and remove the gear.
  18.  

To install:

  1. Reinstall the cam gear loosely so that it can be turned smoothly by hand.
  2.  
  3. Slide the timing belt back over the gears and note the following: the belt should be properly tensioned between the pulleys, the cogs and the belt and the gears should be properly engaged, the crankshaft should not be turned and the belt slack should be concentrated at the two tension pulleys. Push the tension pulley in with your finger and install the tension spring.
  4.  
  5. Partially tighten the tension pulley bolts in sequence (top first, bottom second) so as to prevent any movement of the pulley.
  6.  
  7. Tighten the camshaft gear retaining bolt to 45 ft. lbs. Remove the injection pump gear lockbolt.
  8.  
  9. Remove the fixing plate from the end of the cam.
  10.  
  11. Install the crankshaft damper pulley and then check that the No. 1 piston is still at TDC. Do not try to adjust it by moving the crankshaft.
  12.  
  13. Check that the marks on the injection pump gear and the front plate are still aligned and that the fixing plate still fits properly into the slot on the camshaft.
  14.  
  15. Loosen the tensioner pulley and plate bolts, concentrate the looseness of the timing belt around the tensioner and then tighten the bolts.
  16.  
  17. Belt tension should be 46-63 lbs. checked at a point midway between the upper two pulleys.
  18.  
  19. Remove the damper pulley again and install the belt holder in position away from the timing belt.
  20.  
  21. Installation of the remaining components is in the reverse order of removal.
  22.  

 
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