Quest 1995-1996

Camshaft, Bearings & Lifters

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Bearing Replacement



Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

  1. Remove the cylinder head.
  2.  
  3. If not removed during cylinder head removal, remove the rocker arm shafts, and the rocker arm shaft supports with the lifters.
  4.  
  5. Remove and discard the camshaft oil seal. Please refer to Camshaft and Crankshaft Front Seals, Removal and Installation for the procedure.
  6.  
  7. Measure and record the camshaft end-play. Please refer to Inspection, Camshaft End-Play for the procedure.
  8.  
  9. Remove the three bolts from the camshaft end plate and remove the plate.
  10.  
  11. Temporarily install the camshaft sprocket and bolt.
  12.  
  13. Remove the camshaft thrust plate. A special tool is recommended to hold the camshaft sprocket in position while removing the camshaft thrust plate bolt, however, if the special tool is not available, use the following procedure. Insert a large punch or drift through a hole in the camshaft sprocket. To prevent damaging the head, place a rag over the rocker arm cover mating surface of the cylinder head. Rotate the camshaft clockwise until the tool makes contact with the rag. Hold the tool securely in place and remove the thrust plate bolt.
  14.  
  15. Remove the camshaft thrust plate.
  16.  
  17. Remove the camshaft sprocket.
  18.  
  19. Gently slide the camshaft out of the cylinder head, being careful not to damage the cylinder head bearing surfaces or the camshaft.
  20.  

To install:

  1. Coat the camshaft journals and lobes with new engine oil.
  2.  
  3. Gently slide the camshaft into the cylinder head, being careful not to damage the cylinder head bearing surfaces or the camshaft.
  4.  
  5. Temporarily install the camshaft sprocket and bolt.
  6.  
  7. If the camshaft end-play was not within specifications during disassembly, a different thickness thrust plate must be installed. For thrust plate identification and specifications, please refer to the graphics. If a new camshaft is being installed, measure the camshaft end-play. Please refer to Inspection, Camshaft End-Play for the procedure.
  8.  
  9. Install the camshaft thrust plate and bolt. Tighten the bolt to 58-65 ft. lbs. (78-88 Nm).
  10.  
  11. Remove the camshaft sprocket.
  12.  
  13. Install the camshaft end plate.
  14.  
  15. Install the camshaft oil seal. Please refer to Camshaft and Crankshaft Front Seals, Removal and Installation for the procedure.
  16.  
  17. Install the cylinder head.

    Click image to see an enlarged view

    Fig. Hold the camshaft sprocket in place to remove and install the thrust plate bolt



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    Fig. Removing the camshaft end plate bolts



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    Fig. Camshaft thrust plate identification

  18.  

Camshaft Front Seal Replacement



Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

  1. Remove the timing belt.
  2.  
  3. Remove both camshaft sprockets. A special tool is recommended to hold the camshaft sprockets in position while removing the sprocket bolts, however, if the special tool is not available, use the following procedure. For each sprocket, wrap a rag around the outer edge of the sprocket. Grip the rag and sprocket with a large pair of water pump pliers, being careful not to damage the sprocket. Remove the sprocket bolt and the sprocket.
  4.  
  5. For the right cylinder head seal, wrap a screwdriver with a rag and pry the seal from the head, being careful not to damage the head. The use of a special seal remover is recommended for the removal of the left camshaft seal, however, if the seal remover tool is not available, use the following procedure. Place a small cold chisel or punch at the outer edge of the seal at approximately a 45° angle. Carefully tap the tool with a hammer to collapse the metal rim of the seal, being careful not to damage the camshaft or the cylinder head. Pry the seal from the head.
  6.  

To install:

  1. Apply a small amount of engine oil to the inner lip of the new seal.
  2.  
  3. Using a seal driver or large socket that matches the diameter of the outer edge of the seal, drive the seal into the cylinder head.
  4.  
  5. Install the sprocket. Note that the sprockets are marked with L3 to designate the left (front) camshaft sprocket and R3 to designate the right (rear) camshaft sprocket.
  6.  
  7. Install the sprocket bolts and tighten to 58-65 ft. lbs. (78-88 Nm).
  8.  
  9. Install the timing belt.

    Click image to see an enlarged view

    Fig. Using a special tool to hold the camshaft sprocket in position



    Click image to see an enlarged view

    Fig. Camshaft seal installation

  10.  

Inspection



Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

Clean the camshaft with solvent and dry it. Visually inspect the camshaft lobes and journals for damage or wear. If any lobes or journals are questionable, perform the following measurements. For specifications, please refer to Engine Mechanical Specifications, Camshaft Specifications.

Camshaft

Please refer to Engine Mechanical, Camshaft, Inspection for the measurement and inspection procedures.

End Play

Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

To check end-play, the camshaft and camshaft thrust plate must be installed in the cylinder head. The camshaft sprocket should not be installed on the cam. Position a dial indicator with the stem on the end of the camshaft. Move the camshaft backward in the cylinder head, then zero the dial indicator. Move the camshaft forward and note the reading, which is the camshaft end-play.

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Fig. Proper dial indicator positioning for measuring camshaft end-play

Journal Oil Clearance

Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

The camshaft journal oil clearance is the difference between the outer diameter of the camshaft journal and the inner diameter of the corresponding bearing surface in the cylinder head.

While the camshaft is still removed from the cylinder head, measure the outer diameter of the camshaft bearing journals with a micrometer. Record the measurements, if they are within specifications. If the measurements are less than specifications, the camshaft is worn and must be replaced.

Using an bore gauge or inside micrometer, measure the inner diameter of the camshaft bearings. Record the measurements, if they are within specifications. If the bearing inner diameters are greater than specifications, the cylinder head must be replaced, since the camshafts run directly on the cylinder head surface.

To find the camshaft journal oil clearance for each journal, subtract the previously recorded camshaft journal outer diameter from the recorded inner diameter of the corresponding bearing.

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Fig. Measuring the camshaft journal outer diameter to determine journal clearance



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Fig. Measuring camshaft bearing inner diameter to determine journal clearance

Lobe Height

Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

Camshaft lobe height should be checked when the camshaft has been removed from the engine. Use a micrometer to check the height of each lobe, making sure the anvil and the spindle of the micrometer are positioned directly on the heel and tip of the camshaft lobe, as shown in the accompanying illustration.

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Fig. Proper micrometer positioning for measuring camshaft lobe height

Runout

Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

Camshaft run-out should be checked when the camshaft has been removed from the engine. An accurate dial indicator is needed for this procedure. To measure camshaft run-out, position the camshaft end journals on V-blocks, and position the dial indicator stem on the center bearing journal. Rotate the camshaft by hand to the lowest reading. Zero the dial indicator, then rotate the camshaft to the highest reading, which is the camshaft run-out.

Click image to see an enlarged view

Fig. Proper dial indicator positioning for measuring camshaft run-out

 
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