GM Lumina/Silhouette/Transport APVs 1990-1999 Repair Guide

Camshafts, Bearings, and Lifters

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Specific directions for the removal and installation of many of the following components have already been given in previous sections. Only the basic instructions for removal of the components will be given here. For more detailed instructions on the repair procedures, and the special tools necessary to perform those procedures, refer to the separate component listings given earlier in this section of the manual.

REMOVAL AND INSTALLATION



Camshaft and Bearings
3.1L ENGINE

The camshaft is cast alloy iron with tapered 13.2mm wide lobes, with the exception of lobes 2 and 10, which are 11.2mm wide. It is offset from the lifters and tapered to provide positive valve lifter rotation. The camshaft is supported by four journals and includes an oil pump drive gear and a fuel pump eccentric.

  1. Remove the engine from the vehicle and place on a suitable holding fixture.
  2.  
  3. Remove the valve covers.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the valve rocker arms and pushrods.±
  8.  
  9. Remove the valve lifters.
  10.  
  11. Remove the crankcase front cover.
  12.  
  13. Remove the timing chain and sprocket.
  14.  
  15. Remove the camshaft.
  16.  
  17. To remove the camshaft bearings use the special bearing tool (J 33049).
  18.  
  19. Select the proper pilot, nut and thrust washer.
  20.  
  21. Assemble the bearing puller. Make sure the puller nut engages a sufficient number of threads to pull out the bearings.
  22.  

All the camshaft bearings are the same diameter and care must be taken in removing the camshaft to avoid damage to bearings. Never reuse camshaft bearings once they have been removed.

  1. Inspect the camshaft sprocket, keyway and threads. Inspect the bearing surfaces and lobes for: wear, galling, and gouges, overheating (bluing) discoloration.
  2.  

Whenever a new camshaft is installed, coat the camshaft lobes and journals with camshaft and lifter prelube.

To install:
  1. Select the front, rear, and intermediate camshaft bearings to be installed.

    Select the proper expander assembly and driving washer.
     
    Assemble the installation tool according to manufacturer's recommendations.
     
    Index the bearing oil holes with engine block oil passages.
     
    Secure an intermediate bearing onto the tool. Drive the intermediate camshaft bearings into place.
     
    Place #1 or #4 camshaft bearing onto the tool and index the oil holes. Drive the outer camshaft bearings into place.
     

  2.  
  3. With a piece of 3 / 32 inch brass rod with a 90°bend at the end, probe the bearing oil holes and verify that they are properly aligned.
  4.  


CAUTION
Proper alignment of the oil holes is critical. Restriction of the oil flow will cause severe engine damage.

  1. Lubricate the camshaft journals with engine oil.
  2.  
  3. Install the camshaft.
  4.  
  5. Install the timing chain, and the crankcase front cover.
  6.  
  7. Install the valve lifters and attaching parts.
  8.  
  9. Install the remaining components, and the engine assembly.
  10.  

3.4L ENGINE

The special tool required to perform this repair procedure is: Camshaft Bearing Remover/Installer

  1. Remove the intake manifold.
  2.  
  3. Remove the rocker arm covers, rocker arms, pushrods, and lifter assemblies.
  4.  
  5. Remove the oil pump driven gear assembly.
  6.  
  7. Remove the right side tire and wheel assembly, remove the inner splash shield.
  8.  
  9. Remove the crankshaft pulley.
  10.  
  11. Remove the front cover.
  12.  
  13. Remove the timing chain and sprockets.
  14.  
  15. Remove the camshaft thrust plate, and camshaft.
  16.  
  17. Remove the camshaft rear cover.
  18.  
  19. Assemble the camshaft bearing removal tool according to the manufacturer's recommendations. Tighten the expander assembly snug against the camshaft bearing.
  20.  
  21. Remove the bearings (drive out) and discard; never reuse camshaft bearings once they have been removed. Always install new bearings.
  22.  

When removing or installing a camshaft, avoid marring the bearing surfaces.

To install:
  1. Select the front, rear, and intermediate camshaft bearings to be installed.

    Select the proper expander assembly and driving washer.
     
    Assemble the installation tool according to manufacturer's recommendations.
     
    Index the bearing oil holes with engine block oil passages.
     
    Secure the intermediate bearing onto the tool. Index the oil hole at 4 o'clock when looking from the front of the engine block. Drive the intermediate camshaft bearings into place.
     
    Place #1 or #4 camshaft bearing onto the tool and index the oil holes at 3 and 6 o'clock respectively when looking from the front of the engine block. Drive the outer camshaft bearings into place.
     

  2.  
  3. With a piece of 3 / 32 inch brass rod with a 90° bend at the end, probe the bearing oil holes and verify that they are properly aligned.
  4.  


WARNING
Proper alignment of the oil holes is critical. Restriction of the oil flow will cause severe engine damage.

  1. Apply a suitable sealer to the rear camshaft cover and then install the camshaft cover flush with the engine block.
  2.  

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: View of the special tool needed to install the camshaft bearings

  1. Liberally coat the camshaft with a suitable prelube before installation.
  2.  

Camshaft journals are the same diameter so care must be used when installing the camshaft to avoid bearing damage.

  1. Use of a large screwdriver inserted in the camshaft bolt hole will help ease installation of the shaft into the bearings. Rotating the camshaft back and forth will also help with the installation.
  2.  
  3. Install the camshaft, the camshaft thrust plate, And the timing chain and sprockets.
  4.  
  5. Install the front cover, the crankshaft sensor shield, and the crankshaft pulley.
  6.  

Dip the valve lifters in prelube or equivalent before installation.

  1. Install the pushrods, rocker arms, and rocker arm covers.
  2.  
  3. Install the oil pump driven gear assembly.
  4.  
  5. Install the intake manifold.
  6.  
  7. Change the oil, and fill the fluids.
  8.  

3.8L ENGINE

The special tool required to perform this repair procedure is a camshaft bearing remover/installer.

  1. Remove the intake manifold.
  2.  
  3. Remove the rocker arm covers, the rocker arms, and the pushrods.
  4.  
  5. Remove the lifter guides, and the lifters.
  6.  
  7. Remove the crankshaft pulley, and the crankshaft sensor shield.
  8.  
  9. Remove the timing chain front cover.
  10.  
  11. Remove the timing chain and sprockets.
  12.  
  13. Remove the camshaft thrust plate, then remove the camshaft.
  14.  
  15. Remove the camshaft rear plug.
  16.  

When removing or installing the camshaft, avoid marring the bearing surfaces.

  1. Assemble the camshaft bearing tool removal tool according to the manufacturer's recommendations. Tighten the expander assembly snug against the camshaft bearing.
  2.  
  3. Remove the bearings (drive out) and discard; never reuse camshaft bearings once they have been removed. Always install new bearings.
  4.  

See Figure 2

Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the camshaft and related components-3.8L engine

To install:
  1. Select the front, rear, and intermediate camshaft bearings to install.
  2.  
  3. Select the proper expander assembly and driving washer.
  4.  
  5. Assemble the installation tool according to manufacturer's recommendations.
  6.  
  7. Index the bearing oil holes with engine block oil passages.
  8.  
  9. Secure an intermediate bearing onto the tool. Index the oil hole with the engine block. Drive the intermediate camshaft bearings into place.
  10.  
  11. Place #1 or #4 camshaft bearing onto the tool and index the oil holes. Drive the outer camshaft bearings into place.
  12.  
  13. With a piece of 3 / 32 inch brass rod with a 90°bend at the end, probe the bearing oil holes and verify that they are properly aligned.
  14.  


CAUTION
Proper alignment of the oil holes is critical. Restriction of the oil flow will cause severe engine damage.

  1. Lubricate the camshaft journals liberally with engine oil.
  2.  
  3. Apply a suitable sealer to the rear camshaft cover and then install the camshaft cover flush with the engine block.
  4.  
  5. Liberally coat the camshaft with prelube before installation.
  6.  
  7. Install the camshaft, and the camshaft thrust plate.
  8.  
  9. Install the timing chain and sprockets, be sure the timing marks are aligned.
  10.  
  11. Install the front cover.
  12.  
  13. Install the crankshaft sensor shield, and the crankshaft pulley.
  14.  
  15. Dip each of the valve lifters in prelube before installation, install the lifters and lifter guides.
  16.  
  17. Install the pushrods, install the rocker arms, and the rocker arm covers.
  18.  
  19. Install the intake manifold.
  20.  

Valve Lifters

3.1L ENGINE

If the lifters are removed, they must be reinstalled in their original location. If replacement is necessary use lifters with a narrow flat ground along the lower 3 / 4 of the lifter. These flats provide additional oil to the cam lobe and lifter surfaces.

  1. Drain and recycle the engine coolant.
  2.  
  3. Remove the rocker arm covers, remove the rocker assemblies, and pushrods.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the valve lifter.
  8.  

See Figures 3, 4, 5 and 6

Click image to see an enlarged view

Fig. Fig. 3: Valve lifter operation-3.1L engine



Click image to see an enlarged view

Fig. Fig. 4: Removing the lifter lock down; it holds lifters in place and does not let them rotate.



Click image to see an enlarged view

Fig. Fig. 5: Removing the lifter from its bore by pulling it straight up



Click image to see an enlarged view

Fig. Fig. 6: The bottom side of the lifter is where the roller contacts the cam.

To install:

Whenever new valve lifters are being installed, coat the base of the lifter with prelube, or soak it in oil. In addition, coat the cam lobes with oil.

  1. Install the valve lifter.
  2.  
  3. Install the pushrods, the rocker assemblies, and set the valve lash.
  4.  
  5. Install the intake manifold, and the rocker covers.
  6.  
  7. Replace the fluids, change the oil.
  8.  

3.4L ENGINE
  1. Remove the valve covers.
  2.  
  3. Remove the upper intake manifold, remove the lower intake manifold.
  4.  
  5. Remove the valve rocker arms and pushrods.±
  6.  
  7. Remove the lifter guide bolts, remove the lifter guide, and remove the lifter.
  8.  

To install:
  1. Coat the lifters with prelube
  2.  
  3. Install the lifters to the same location from which they were removed.
  4.  
  5. Install the lifter guide, install the lifter guide bolts and tighten to 10N.m (89lb. in.).
  6.  
  7. Install the valve rocker arms and pushrods.
  8.  
  9. Install the lower intake manifold, install the upper intake manifold.
  10.  
  11. Install the valve rocker arm covers.
  12.  
  13. Reverse the removal process to complete the repair procedure.
  14.  

3.8L ENGINE
  1. Remove the rocker arm covers.
  2.  
  3. Remove the intake manifold.
  4.  
  5. Remove the rocker arms and pedestals.
  6.  

Be sure to keep all valve train parts in order so they may be reinstalled in their original locations and with the same mating surfaces as when removed.

  1. Remove the pushrods.
  2.  
  3. Remove the guide retainer bolts and retainer.
  4.  
  5. Remove the lifter guides, and the valve lifters.
  6.  

See Figures 7 through 13

Click image to see an enlarged view

Fig. Fig. 7: Unfasten the lifter guide bolt (see arrows); there are two for each side



Click image to see an enlarged view

Fig. Fig. 8: Once the bolts are removed, remove the lifter guide



Click image to see an enlarged view

Fig. Fig. 9: View into top of lifters at pushrod seat with the lifter guide and pushrods removed



Click image to see an enlarged view

Fig. Fig. 10: Pull the lifter straight up to remove it from the bore. The lifter is keyed at the top to fit in the guide without rotating.



Click image to see an enlarged view

Fig. Fig. 11: The bottom of lifter rides against the cam lobe. The roller reduces friction and gives the lifter its name



Click image to see an enlarged view

Fig. Fig. 12: The pushrod seats in the top of the lifter.



Click image to see an enlarged view

Fig. Fig. 13: View of the lifter and pushrod; the hole in the pushrod carries oil for lubrication.

  1. Clean all gasket surfaces with degreaser. Clean the valve train parts, using a suitable solvent. Inspect the valve train parts. Inspect the lifters and cam lobes for wear.
  2.  

To install:
  1. Dip the valve lifters in prelube before installation.
  2.  
  3. Install the lifter guides, and guide retainer. Tighten bolts to 27 ft. lbs. (37 Nm).
  4.  
  5. Install the pushrods, rocker arms, and pedestals.
  6.  
  7. Apply thread lock to the bolt threads to prevent them from backing out. Install the bolts and tighten to 19 ft. lbs. (25 Nm), plus an addition 70° rotation.
  8.  
  9. Install the intake manifold and gaskets.
  10.  
  11. Install the rocker arm covers and gaskets.
  12.  
  13. The remainder of installation is the reverse of the removal procedure.
  14.  

 
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