Nissan Pick-ups and Pathfinder 1970-1988

Camshaft

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REMOVAL & INSTALLATION



See Figure 4

L16, L18 and L20B Engines

See Figures 1, 2 and 3

Removal of the cylinder head from the engine is optional. Mark and keep all parts in order for correct installation.

  1. Remove the camshaft sprocket from the camshaft together with the timing chain. Refer to the Timing Chain procedures if necessary.
  2.  
  3. Loosen the valve rocker pivot lock-nut and remove the rocker arm by pressing down on the valve spring.
  4.  
  5. Remove the two retaining nuts on the camshaft retainer plate at the front of the cylinder head and carefully slide the camshaft out (towards the front of the vehicle) of the camshaft carrier.
  6.  

To install:
  1. Check camshaft runout, end-play, wear and journal clearance as described in this section.
  2.  
  3. Lightly coat the camshaft bearings with clean motor oil and carefully slide the camshaft into place in the camshaft carrier.
  4.  
  5. Install the camshaft retainer plate with the oblong groove in the face of the plate facing toward the front of the engine.
  6.  
  7. Check the valve timing as outlined under Timing Chain Removal and Installation and install the timing sprocket on the camshaft, tightening the bolt together with the fuel pump cam (gasoline engines only) to 86-116 ft. lbs. (117-158 Nm).
  8.  
  9. Install the rocker arms by pressing down the valve springs with a screwdriver and install the valve rocker springs.
  10.  
  11. Install the cylinder head, if it was removed, and assemble the rest of the engine.
  12.  
  13. Start the engine and run it until it reaches normal operating temperature. Remove cylinder head cover, check and adjust valves if necessary. Install the cylinder head cover with a new gasket and check for oil leaks.
  14.  



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Fig. Fig. 1: Camshaft locating plate-L16, L18 and L20B engines



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Fig. Fig. 2: Removing the camshaft-all 4-cylinder gasoline engines



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Fig. Fig. 3: Adjusting the camshaft sprocket location-L16, L18 and L20B engines



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Fig. Fig. 4: Removing the camshaft most models similar

Z20, Z22, Z24 and Z24i Engines

See Figures 5 and 6

Removal of the cylinder head from the engine is optional. Mark and keep all parts in order for correct installation.

  1. Set the No. 1 piston at TDC on its compression stroke, then remove the camshaft sprocket from the camshaft together with the timing chain.
  2.  
  3. Loosen the bolts holding the rocker shaft assembly in place and remove the six center bolts. Do not pull the four end bolts out of the rocker assembly because they hold the unit together.
  4.  

When loosening the bolts, work from the ends in and loosen all of the bolts a little at a time so that you do not strain the camshaft or the rocker assembly. Remember, the camshaft is under pressure from the valve springs!

  1. After removing the rocker assembly, remove the camshaft. Slide the camshaft carefully out of the front of the vehicle.
  2.  

Mark and keep the disassembled parts in order.

  1. If you disassembled the rocker unit, prepare it for installation. Install the mounting brackets, valve rockers and springs observing the following considerations:
    1. The two rocker shafts are different. Both have punch marks in the ends that face the front of the engine. The rocker shaft that goes on the side of the intake manifold has two slits in its end just below the punch mark. The exhaust side rocker shaft does not have slits.
    2.  
    3. The rocker arms for the intake and exhaust valves are interchangeable between cylinders one and three and are identified by the mark 1 . Similarly, the rockers for cylinders two and four are interchangeable and are identified by the mark 2 .
    4.  
    5. The rocker shaft mounting brackets are also coded for correct placement with either an A or a Z plus a number code.
    6.  

  2.  
  3. Check camshaft runout, end-play wear and journal clearance as described in this section.
  4.  
  5. Apply sealant to the end camshaft saddles. Place the camshaft on the head with its knockpin pointing up.
  6.  
  7. Fit the rocker assembly on the head, making sure you mount it on its knock pin.
  8.  
  9. Tighten the bolts to 11-18 ft. lbs. (15-25 Nm), in several stages working from the middle bolts and moving outwards on both sides.
  10.  

Make sure that the engine is at TDC of the compression stroke for the No. 1 piston or you may damage some valves.

  1. Adjust the valves.
  2.  



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Fig. Fig. 5: Make sure that the camshaft is installed with the knockpin UP-Z20, Z22, Z24, Z24i engines



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Fig. Fig. 6: Apply sealer here-Z20, Z22, Z24, Z24i engines

VG30i Engines

See Figures 7 and 8

With the engine still mounted in the vehicle, Nissan recommends that the cylinder heads be removed from the engine, before removing the camshafts.

  1. Remove the timing belt. Remove the cylinder head.
  2.  
  3. With cylinder head mounted on a suitable workbench, remove the rocker shafts with rocker arms. Bolts should be loosened in two or three stages.
  4.  

Hold the valve lifters with wire so that they will not drop from the lifter guide. Put an identification mark on the lifters to avoid mixing them up.

  1. At the rear of the cylinder head, remove the cylinder head rear cover, camshaft bolt and the locating plate.
  2.  
  3. Remove the camshaft front oil seal and then slide the camshaft out the front of the cylinder head assembly.
  4.  

To install:
  1. Install camshaft, locator plate, cylinder head rear cover and front oil seal. Set the camshaft knock pin at the 12:00 o'clock position (straight up). Install cylinder head with new gasket to engine.
  2.  
  3. Install valve lifter guide assembly, being sure to assemble the valve lifters in their original positions. After installing them in the correct location, remove the wire holding them in lifter guide.
  4.  
  5. Install the rocker shafts in position with their rocker arms. Tighten the bolts in two or three stages to 13-16 ft. lbs (18-22 Nm). Before tightening, be sure to set the camshaft lobe in a position where the lobe is not lifted or the valve closed. You can set each cylinder one at a time or follow the procedure below (the timing belt must be installed in the correct position):
    1. Set the No. 1 piston at TDC of its compression stroke and tighten the rocker shaft bolts for the No. 2, No. 4 and No. 6 cylinders.
    2.  
    3. Set the No. 4 piston at TDC of its compression stroke and tighten the rocker shaft bolts for the No. 1, No. 3 and No. 5 cylinders.
    4.  
    5. Tighten the rocker shaft retaining bolts to 13-16 ft. lbs. (18-22 Nm).
    6.  

  6.  
  7. Install the rear timing belt cover and camshaft sprocket. The left and right camshaft sprockets are different parts. Install the correct sprocket in the correct position.
  8.  

The right and left camshaft sprockets are different parts. Install them in their correct positions. The right sprocket has an R3 identification mark and the left has an L3.

  1. Install the timing belt.
  2.  



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Fig. Fig. 7: Hold the valve lifters with wire-V6 engine



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Fig. Fig. 8: Hold the valve lifters with wire-VG30i engine

SD22 and SD25 Engines

See Figure 9

  1. Remove the cylinder head.
  2.  
  3. Remove the valve lifters and mark them for reassembly.
  4.  
  5. Remove the front case and timing gear cover.
  6.  
  7. Remove the tachometer drive support nuts.
  8.  
  9. Remove the timer round nut.
  10.  
  11. Thread the timer extractor, ST #57926-581, into the timer weight holder. Remove the timer assembly by tightening the extractor bolt.
  12.  
  13. Remove the oil pump drive spindle.
  14.  
  15. Remove the camshaft locating plate bolts and carefully slide the camshaft from the engine.
  16.  

To install:
  1. Coat the camshaft with clean engine oil and carefully slide it into the block. Install the locating plate.
  2.  
  3. Install the oil pump drive spindle by aligning the oil pump driveshaft groove and the camshaft oil pump drive gear with the spindle.
  4.  



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Fig. Fig. 9: Removing the camshaft locating bolts-SD22 and SD25 engines

CHECKING CAMSHAFT RUNOUT



See Figure 10

Runout should be checked when the camshaft has been removed from the engine. An accurate dial indicator is needed for this procedure; engine specialists and most machine shops have this equipment. If you have access to a dial indicator, or can take your camshaft to someone who does, measure the camshaft bearing journal runout. The maximum (limit) runout on the L16, L18, L20D, Z20, Z22, Z24 and Z24i camshafts is 0.008 in. (0.2mm). The runout limit on the SD22 and SD25 camshafts is 0.0024 in. (0.06mm). The maximum (limit) runout on the VG30i camshaft is 0.0039 in. (0.1mm) If the runout exceeds the limit replace the camshaft.



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Fig. Fig. 10: Camshaft run-out must be measured with a dial indicator

CHECKING CAMSHAFT LOBE HEIGHT



See Figures 11 and 12

Use a micrometer to check camshaft (lobe) height, making sure the anvil and the spindle of the micrometer are positioned directly on the heel and tip of the camshaft lobe.



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Fig. Fig. 11: Camshaft lobe height should be measured with a micrometer



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Fig. Fig. 12: Measuring the inside diameter of the camshaft saddles to determine journal clearance

CHECKING CAMSHAFT JOURNALS AND CAMSHAFT BEARING SADDLES



See Figure 13

While the camshaft is still removed from the cylinder head, the camshaft bearing journals should be measured with a micrometer. Compare the measurements with those listed in the Camshaft Specifications chart in this section. If the measurements are less than the limits listed in the chart, the camshaft will require replacement, since the camshafts in all of the engines covered in this manual (except the diesels) run directly on the cylinder head surface; no actual bearings or bushings are used, so no oversize bearings or bushings are available.

Using an inside dial gauge or inside micrometer, measure the inside diameter of the camshaft saddles (the camshaft mounts that are either integrally cast as part of the cylinder head, or are a bolted on, one piece unit. The Z-series engines use a saddle-and-cap arrangement. The inside diameter of the saddles on all engines is 1.8898-1.8904 in. (48-48.01mm). On the VG30i engine, contact a Nissan dealer or local machine shop for that specification. The camshaft journal oil clearances are listed in the Camshaft Specifications chart in this section. If the saddle inside diameters exceed those listed above, the cylinder head must be replaced (again, because oversize bearings or bushings are not available).

On the SD22 and SD25, the camshaft runs in bushings. Measure the inside diameter of the camshaft bushing with a dial gauge and the outside diameter of the camshaft journal with a micrometer. The difference between the two measurements should be:



Front-0.0009-0.0040 in. (0.024-0.102mm)
 
Center-0.0015-0.0045 in. (0.037-0.115mm)
 
Rear-0.0009-0.0040 in. (0.024-0.102mm)
 
The limit on all should be a maximum of 0.0059 in. (0.15mm)
 



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Fig. Fig. 13: Measuring outside diameter of the camshaft journals to determine journal clearance

Bushing Replacement
SD22 AND SD25 ENGINES

This procedure will require the use of Nissan special tools #ST16650010, ST16650020, ST16650030 and ST16650040.

  1. Remove the rear camshaft plug.
  2.  
  3. Working from the front side of the engine, press out the camshaft bushings.
  4.  
  5. Install new bushings with the tool so that the beveled ends face forward (front of the engine). Be sure that the oil passage hole in the cylinder block and the oil hole in the bushing are in alignment.
  6.  
  7. Check the bushing oil clearance.
  8.  
  9. Coat a new rear plug with liquid sealant and install it with a brass drift.
  10.  

CHECKING CAMSHAFT ENDPLAY



See Figures 14, 15, 16 and 17

After the camshaft has been installed, end-play should be checked. The camshaft sprocket should not be installed on the cam. Use a dial gauge to check the end-play, by moving the camshaft forward and backward in the cylinder head. Endplay specifications should be as noted in the Camshaft Specifications chart.



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Fig. Fig. 14: Measuring the camshaft end-play-all 4-cylinder gasoline engines



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Fig. Fig. 15: Measuring the camshaft end-play-VG30i engines



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Fig. Fig. 16: Adjusting the camshaft end-play with shims-VG30i engines



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Fig. Fig. 17: Measuring the camshaft end-play-SD22 and SD25 engines

 
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