GM Celebrity/Century/Ciera/6000 1982-1996 Repair Guide

Camshaft

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REMOVAL & INSTALLATION



2.2L Engine

See Figure 1

The engine must be removed from the vehicle for this procedure.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine assembly from the vehicle. Mount the engine on a suitable engine stand.
  4.  
  5. Remove the serpentine drive belt.
  6.  
  7. Remove the serpentine drive belt tensioner assembly with the alternator attached.
  8.  
  9. Detach the strut bracket and the rear alternator bracket.
  10.  
  11. Unbolt the front engine mount bracket.
  12.  
  13. Remove the oil level indicator tube.
  14.  



Click image to see an enlarged view

Fig. Fig. 1: Camshaft and timing chain assembly on the 2.2L engine

  1. Unbolt and remove the oil pan.
  2.  
  3. Remove the crankshaft balancer and front cover.
  4.  
  5. Remove the timing chain and camshaft sprocket.
  6.  
  7. Disconnect the spark plug wires.
  8.  
  9. Remove the rocker arm cover.
  10.  

When removing the valve train components they must be kept in order for installation in the same locations from which they were removed.

  1. Remove the rocker arm nuts, rocker arms, balls and pushrods.
  2.  
  3. Remove the power steering pump brace.
  4.  
  5. Disconnect the cylinder head with the intake and exhaust manifolds attached.
  6.  
  7. Remove the valve lifters.
  8.  
  9. Remove the camshaft thrust plate mounting bolts and the thrust plate.
  10.  
  11. Remove the oil pump assembly.
  12.  
  13. Remove the camshaft carefully from the engine.
  14.  

To install:
  1. Coat the camshaft lobes and bearings with GM Engine Oil Supplement (E.O.S.) 1051396 or equivalent, then insert the camshaft carefully into the engine.
  2.  
  3. Install the oil pump drive assembly.
  4.  
  5. Install the thrust plate, then tighten the mounting bolts to 106 inch lbs. (12 Nm).
  6.  
  7. Install the valve lifters.
  8.  
  9. Attach the cylinder head and manifold assemblies to the engine.
  10.  
  11. Connect the power steering pump brace.
  12.  
  13. Install the pushrods, rocker arms, balls and rocker arms nuts. Tighten the nuts to 22 ft. lbs. (30 Nm).
  14.  
  15. Install the valve cover.
  16.  
  17. Connect the spark plug wires.
  18.  
  19. Install the timing chain and camshaft sprocket. Verify that the camshaft and crankshaft sprocket timing marks are correctly aligned.
  20.  
  21. Install the timing chain front cover and crankshaft balancer.
  22.  
  23. Install the oil pan.
  24.  
  25. Bolt down the oil level indicator.
  26.  
  27. Attach the front engine bracket, rear alternator bracket and strut bracket.
  28.  
  29. Install the drive belt tensioner and alternator assembly, then install the serpentine drive belt.
  30.  
  31. Install the engine assembly into the vehicle.
  32.  
  33. Attach a new oil filter on the engine, then fill the engine crankcase with clean oil.
  34.  
  35. Connect the negative battery cable.
  36.  
  37. Fill the cooling system with new coolant.
  38.  
  39. Start the vehicle, top off the coolant, check for leaks.
  40.  

2.5L Engine

See Figures 2, 3 and 4

  1. Relieve the pressure in the fuel system before disconnecting any fuel line connections.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the engine as previously outlined, and support it on a suitable engine stand.
  6.  
  7. Unbolt the rocker cover, rocker arms and pushrods.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: Remove the camshaft thrust plate screws by working through the holes in the gear

  1. Remove the spark plugs and fuel pump on carbureted models.
  2.  
  3. Unsecure the pushrod cover and gasket. Remove the lifters.
  4.  
  5. Remove the alternator, the alternator lower bracket and the front engine mount bracket assembly.
  6.  
  7. Remove the oil pump driveshaft and gear assembly.
  8.  
  9. Remove the crankshaft hub and timing gear cover.
  10.  
  11. Unfasten and remove the 2 camshaft thrust plate screws by working through the holes in the gear.
  12.  



Click image to see an enlarged view

Fig. Fig. 3: A press is needed to remove the camshaft timing gear

  1. Remove the camshaft and gear assembly by pulling it through the front of the block. Take care not to damage the bearings.
  2.  
  3. If replacement of the camshaft gear is necessary, use the following procedure:
  4.  



Click image to see an enlarged view

Fig. Fig. 4: Measure the end clearance of the thrust plate

  1. Remove the camshaft gear using an arbor press and adapter.
  2.  
  3. Position the thrust plate to avoid damage by interference with the key as the gear is removed.
  4.  
  5. When assembling the gear onto the camshaft, support the camshaft at the back of the front journal in the arbor press using press plate adapters.
  6.  
  7. Press the gear on the shaft until it bottoms against the spacer ring.
  8.  
  9. Measure the end clearance of the thrust plate. End clearance should be 0.0015-0.0050 in. (0.0381-0.1270mm).
  10.  
  11. If clearance is less than 0.0015 in. (0.0381mm), replace the spacer ring.
  12.  
  13. If clearance is more than 0.0050 in. (0.127mm), replace the thrust plate.
  14.  

To install:
  1. Lubricate the camshaft journals with a high quality engine oil supplement and carefully install the camshaft and gear into the cylinder block.
  2.  
  3. Rotate the camshaft and crankshaft so the timing marks on the gear teeth align. The engine is now in No. 4-cylinder firing position.
  4.  
  5. Install the camshaft thrust plate-to-block screw. Tighten the screw to 90 inch lbs. (10 Nm).
  6.  
  7. Attach the crankshaft hub and timing gear cover.
  8.  
  9. Install the oil pump driveshaft and gear assembly.
  10.  
  11. Attach the lower alternator bracket, alternator and the front engine mount bracket assembly.
  12.  
  13. Install the spark plugs and fuel pump.
  14.  
  15. Install the lifters. Install the pushrod cover and gasket.
  16.  
  17. Install the pushrods, rocker arms and rocker cover.
  18.  
  19. Place and attach the engine in the vehicle.
  20.  
  21. Connect the negative battery cable.
  22.  

2.8L Engine
  1. Relieve the pressure in the fuel system before disconnecting any fuel line connections.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the engine as previously outlined, and support it on a suitable engine stand.
  6.  
  7. Remove the intake manifold, valve cover, rocker arms, pushrods and valve lifters.
  8.  
  9. Remove the crankshaft balancer and front cover.
  10.  
  11. Remove the timing chain and sprockets.
  12.  
  13. Carefully remove the camshaft. Avoid marring the camshaft bearing surfaces.
  14.  

To install:
  1. Coat the camshaft with lubricant 1052365 or equivalent, and install the camshaft.
  2.  
  3. Install the timing chain and sprocket.
  4.  
  5. Install the camshaft thrust button and front cover.
  6.  
  7. Install the crankshaft balancer.
  8.  
  9. Install the intake manifold, valve cover, rocker arms, pushrods and valve lifters.
  10.  
  11. Install the engine in the vehicle.
  12.  
  13. Connect the negative battery cable.
  14.  
  15. Adjust the valves, as required.
  16.  

3.0L Engine
  1. Disconnect the battery cables.
  2.  
  3. Remove the engine as described earlier.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the valve covers.
  8.  
  9. Remove the rocker arm assemblies, pushrods and lifters.
  10.  
  11. Remove the timing cover, chain and camshaft sprocket. This will avoid burring of the camshaft journals by the crankshaft during removal. Slide the camshaft forward out of the bearing bores carefully to avoid marring the bearing surfaces.
  12.  

To install:
  1. When replacing the camshaft, take extra care to avoid marring the bearing surfaces.
  2.  
  3. Install the valve mechanism.
  4.  
  5. Attach the intake manifold to the engine.
  6.  
  7. Install the engine.
  8.  
  9. Connect the battery cables, start the engine, and check for leaks.
  10.  

3.1L Engine (VIN T)
  1. Remove the engine as previously outlined earlier in this section.
  2.  
  3. Remove the valve lifters, then remove the front cover.
  4.  
  5. Remove the timing chain and sprocket.
  6.  
  7. Slide the camshaft from the engine, take care not to damage the camshaft bearings. The journals are the same diameter.
  8.  

To install:
  1. Coat the camshaft lobes and bearings with GM Engine Oil Supplement (E.O.S.) 1051396 or equivalent, then insert the camshaft carefully into the engine.
  2.  
  3. Lubricate the camshaft journals with engine oil.
  4.  
  5. Install the camshaft.
  6.  
  7. Attach the timing chain and sprocket.
  8.  
  9. Install the crankcase front cover.
  10.  
  11. Install the lifters.
  12.  
  13. Install the engine.
  14.  
  15. Fill the engine crankcase with clean engine oil. Fill the cooling system.
  16.  
  17. Double check everything has been connected, start the engine, top off the cooling system, then check for leaks.
  18.  

3.1L Engine (VIN M)

CAUTION
Fuel Injection systems remain under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.

  1. Relieve the fuel system pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the engine assembly.
  6.  

When removing valve train components they must be marked for installation in the same location they are removed from. When the camshaft is being replaced the valve lifters should also be replaced.

  1. Remove the intake manifold, valve cover, rocker arms, pushrods and valve lifters.
  2.  
  3. Remove the crankshaft balancer and front cover.
  4.  
  5. Remove the timing chain and sprockets.
  6.  
  7. Remove the oil pump driven gear mounting bolt and remove the oil pump driven gear.
  8.  
  9. Remove the two bolts and remove the camshaft thrust plate.
  10.  
  11. Carefully remove the camshaft. Avoid marring the camshaft bearing surfaces.
  12.  

To install:
  1. Coat the camshaft with lubricant 1052365 or equivalent, and install the camshaft.
  2.  
  3. Attach the camshaft thrust plate and tighten the mounting bolts to 89 inch lbs. (10 Nm).
  4.  
  5. Install the oil pump driven gear and tighten the mounting bolt to 27 ft. lbs. (36 Nm).
  6.  
  7. Install the timing chain and sprocket.
  8.  
  9. Attach the camshaft thrust button and front cover.
  10.  
  11. Install the crankshaft balancer.
  12.  
  13. Install the intake manifold, valve cover, rocker arms, pushrods and valve lifters.
  14.  
  15. Install the engine assembly.
  16.  
  17. Connect the negative battery cable.
  18.  
  19. Adjust the valves, as required.
  20.  
  21. Add engine and coolant as required.
  22.  
  23. Start the engine and verify no oil leaks.
  24.  

3.8L Engine
  1. Relieve the pressure in the fuel system before disconnecting any fuel line connections.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the engine as previously outlined, and support it on a suitable engine stand.
  6.  
  7. Remove the intake manifold.
  8.  
  9. Unbolt and remove the valve covers.
  10.  
  11. Remove the rocker arm assemblies, pushrods and lifters.
  12.  
  13. Unbolt and remove the timing chain cover.
  14.  

Align the timing marks of the camshaft and crankshaft sprockets to avoid burring the camshaft journals by the crankshaft.

  1. Remove the timing chain, camshaft sensor magnet assembly and sprockets.
  2.  

To install:
  1. Coat the camshaft with lubricant 1052365 or equivalent, and install the camshaft.
  2.  
  3. Install the timing chain, camshaft sensor magnet assembly and sprockets.
  4.  
  5. Install the camshaft thrust button and front cover.
  6.  
  7. Complete installation by reversing the removal procedure.
  8.  
  9. Add engine oil and coolant as required.
  10.  
  11. Connect battery negative cable.
  12.  

4.3L Diesel Engine

This procedure requires the removal, disassembly, cleaning, reassembly and bleed-down of all the valve lifters. Read that procedure, described earlier, before proceeding.

  1. Remove the engine as described earlier.
  2.  
  3. Remove the intake manifold.
  4.  
  5. Remove the oil pump drive assembly.
  6.  
  7. Unbolt the timing chain cover.
  8.  
  9. Align the timing marks.
  10.  
  11. Remove the rocker arms, pushrods and lifters, keeping them in order for reassembly.
  12.  
  13. Remove the timing chain and camshaft lifters, keeping them in order for reassembly.
  14.  
  15. Remove the camshaft bearing retainer.
  16.  
  17. Remove the cam sprocket key.
  18.  
  19. Remove the injection pump drive gear.
  20.  
  21. Remove the injection pump driven gear, intermediate pump adapter and pump adapter. Remove the snapring and selective washer. Remove the driven gear and spring.
  22.  
  23. Carefully slide the camshaft out of the block.
  24.  
  25. If the camshaft bearings are being replaced, you'll have to remove the oil pan.
  26.  
  27. Installation is the reverse of removal. Perform the complete valve lifter bleed-down procedure mentioned earlier.
  28.  

INSPECTION



Degrease the camshaft, using solvent, and clean out all oil holes. Visually inspect cam lobes and bearing journals for excessive wear. If a lobe is questionable, check all lobes as indicated below. If a journal or lobe is worn, the camshaft must be reground or replaced.

Inspect the sprocket, key way and threads, bearing surfaces and lobes for: wear, galling, gouges, and overheating.

Do not attempt to repair a camshaft, replace it if damaged. If a new camshaft is installed, all the valve lifters must be replaced.

Measure the bearing journals, with a micrometer, measure the diameter and run-out. If out of specification, replace the camshaft. Measure the camshaft lift, lubricate the journal bearings with GM 1052365 or equivalent. Carefully set the camshaft on "V" blocks or between the camshaft centers. With dial indicators, measure the cam lift. If out of specification, replace the cam.

 
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