GM Corvette 1984-1996 Repair Guide

Timing Chain and Sprockets

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REMOVAL & INSTALLATION



5.7L (VIN 8) Engine

See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine front cover.
  4.  
  5. Rotate the crankshaft and align the timing marks.
  6.  



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Fig. Fig. 1: The timing marks MUST be aligned before proceeding

  1. Unfasten the camshaft sprocket retaining bolt(s).
  2.  
  3. Remove the timing chain and camshaft sprocket as an assembly.
  4.  
  5. If necessary, remove the crankshaft sprocket using a suitable puller.
  6.  



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Fig. Fig. 2: Exploded view of the timing chain, sprockets and related components

To install:
  1. If removed, install the crankshaft sprocket.
  2.  
  3. Align the timing marks on the camshaft and crankshaft sprockets.
  4.  
  5. Install the timing chain and camshaft sprocket.
  6.  
  7. Install the camshaft sprocket retaining bolts and tighten to 20 ft. lbs. (27 Nm).
  8.  
  9. Install the front cover in the vehicle, then connect the negative battery cable.
  10.  

5.7L (VIN J) Engine

See Figures 3, 4, 5 and 6

PRIMARY TIMING CHAIN AND CRANKSHAFT SPROCKET
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the timing chain front cover assembly.
  4.  
  5. Remove the left and right intake camshafts.
  6.  
  7. Remove the bolts attaching the primary chain guide to the oil pump, then remove the guide from the vehicle.
  8.  
  9. Remove the idler sprocket assembly attaching bolts, then disengage the primary timing chain from the idler and crankshaft sprockets. Remove the chain from the vehicle.
  10.  
  11. Using the crankshaft torsional damper puller along with J-38211 or equivalent sprocket tool, remove the crankshaft sprocket. Note which side of the sprocket faces forward for installation purposes.
  12.  
  13. Remove the key and oil pump seal seat from the crankshaft.
  14.  



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Fig. Fig. 3: Primary and secondary timing chain assembly-5.7L (VIN J) engine



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Fig. Fig. 4: Timing chain assembly-5.7L (VIN J) engine



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Fig. Fig. 5: Crankshaft sprocket removal-5.7L (VIN J) engine



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Fig. Fig. 6: Installing the crankshaft sprocket-5.7L (VIN J) engine

To install:
  1. Inspect the primary chain guide for excessive wear. Wear groove should not exceed a depth of 0.040 inch (1.0mm). If necessary, replace wear strip.
  2.  
  3. Install oil pump seal seat and key onto the crankshaft.
  4.  
  5. Install the crankshaft sprocket using J-38132 or equivalent sprocket installer. Make sure sprocket is installed with same side to the front as noted during removal, this should be the wide shoulder.
  6.  
  7. Engage the primary chain onto the idler and crankshaft sprocket.
  8.  
  9. Apply Loctite® 262 or equivalent, to the idler sprocket assembly bolts and tighten to 19 ft. lbs. (26 Nm).
  10.  
  11. Apply Loctite® 262 or equivalent, to the primary chain guide bolts. Install the guide and bolts. Push the guide so the slack is removed from the chain and tighten the bolts to 89 inch lbs. (10 Nm).
  12.  

When installing guide, do not use any leverage tools, finger pressure is sufficient.

  1. Install the left and right intake camshafts.
  2.  
  3. Install the timing chain front cover.
  4.  
  5. Connect the negative battery cable.
  6.  

SECONDARY TIMING CHAINS AND IDLER SPROCKET ASSEMBLY
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the camshafts.
  4.  
  5. Remove the primary timing chain and crankshaft sprocket.
  6.  
  7. Disengage the left and right secondary chains from the idler sprocket.
  8.  
  9. Remove the idler sprocket assembly.
  10.  
  11. Remove the left and right secondary chains from the vehicle.
  12.  

To install:
  1. Inspect chains and sprockets for abnormal wear or damage. If abnormal wear or damage is present on either the secondary timing chain, cam sprockets or idler sprockets, the entire assembly must be replaced.
  2.  
  3. Inspect the idler sprocket shaft bearings for wear or damage. If necessary, replace idler sprocket shaft bearings as follows:
    1. Remove the idler sprocket screw, washer and shaft.
    2.  
    3. Using tool J-3628 or equivalent, remove bearings from idler sprocket.
    4.  
    5. When installing bearings, ensure the manufacture's name and part Nos. are visible from either end of the sprocket assembly.
    6.  
    7. Using a press, carefully push in the bearings until they are flush with idler sprocket. Apply minimum pressure to obtain a fit 0.0-1.3mm below the surface.
    8.  

  4.  
  5. Install the shorter (inner) secondary chain through the right head and install J-38099 or equivalent timing chain retaining tool.
  6.  
  7. Locate the right chain onto the rear idler sprocket.
  8.  
  9. Install the longer (outer) secondary chain through the left head and install J-38099 or equivalent timing chain retaining tool.
  10.  
  11. Locate the left chain onto the middle idler sprocket.
  12.  
  13. Install the primary timing chain.
  14.  
  15. Install the camshafts.
  16.  
  17. Connect the negative battery cable.
  18.  

5.7L (VIN P and 5) Engines

See Figures 7 and 8

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the timing chain front cover.
  4.  
  5. Rotate the crankshaft until the timing marks on the timing chain sprockets are aligned nearest each other. The camshaft sprocket mark should be at the 6 o'clock position while the mark on the crankshaft sprocket should be at the 12 o'clock position.
  6.  
  7. Remove the camshaft sprocket bolts.
  8.  
  9. Remove the camshaft sprocket and timing chain.
  10.  



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Fig. Fig. 7: Exploded view of the timing chain, sprockets and related components-5.7L (VIN P and 5) engines



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Fig. Fig. 8: Removal and installation of the crankshaft sprocket-5.7L (VIN P and 5) engines

To prevent piston or valve damage, do not turn the crankshaft after the timing chain has been removed.

  1. Remove the water pump bearing retainer bolts, then remove the driveshaft assembly using J-39243 or equivalent driven gear assembly remover.
  2.  
  3. Remove the crankshaft sprocket using J-5825-A or equivalent crankshaft sprocket remover.
  4.  
  5. If necessary, remove the crankshaft key.
  6.  

To install:
  1. If removed, install the crankshaft key.
  2.  
  3. Install the crankshaft sprocket using a suitable installation tool.
  4.  
  5. Install the water pump driveshaft assembly using a suitable tool. Install the retainer bolts and tighten to 108 inch lbs. (12 Nm).
  6.  
  7. Align the timing marks and install the camshaft sprocket and timing chain. The gears of the camshaft sprocket and water pump driveshaft must mesh or damage to the thrust plate retainer could occur.
  8.  
  9. Install the camshaft sprocket bolts and tighten to 21 ft. lbs. (28 Nm).
  10.  
  11. Install a new O-ring to the water pump driven gear shaft using a suitable seal installation tool.
  12.  
  13. Install the timing chain front cover and connect the negative battery cable.
  14.  

 
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