Jeep CJ/Scrambler 1971-1986 Repair Guide

Oil Pump

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See Figures 1, 2, 3 and 4

REMOVAL & INSTALLATION



4-134 Engine
  1. Set number one piston at TDC in order to reinstall the oil pump without disturbing the ignition timing.
  2.  
  3. Remove the distributor cover and note the position of the rotor. Keep the rotor in that position when the oil pump is installed.
  4.  
  5. Remove the cap screws and lockwashers that attach the oil pump to the cylinder block. Carefully slide the oil pump and its driveshaft out of the cylinder block.
  6.  

The oil pump is driven by the camshaft by means of a spiral gear. The distributor in turn is driven by the oil pump by means of a tongue on the end of the distributor shaft which engages a slot in the end of the oil pump shaft. Because the tongue and the slot are both machined off center, the two shafts can be meshed in only one position. Since the position of the distributor shaft determines the timing of the engine, and is controlled by the oil pump shaft, the position of the oil pump shaft with respect to the camshaft is important. If only the oil pump has been removed, install it so that the slot in the end of the shaft lines up with the tip of the distributor shaft and allows that shaft to slip into it without disturbing the the original position of the distributor. If the engine has been disturbed or both the distributor and the oil pump have been removed, follow the procedure given below.

  1. Turn the crankshaft to align the timing marks on the crankshaft and camshaft timing gears.
  2.  
  3. Install the oil pump gasket on the pump.
  4.  
  5. With the wider side of the slot on top, start the oil pump driveshaft into the opening in the cylinder keeping the mounting holes in the body of the pump in alignment with the holes in the cylinder block.
  6.  
  7. Insert a long blade screwdriver into the distributor shaft opening in the side of the cylinder block and engage the slot in the oil pump shaft. Turn the shaft so that the slot is positioned at what would be roughly the nine thirty position on a clock face.
  8.  
  9. Remove the screwdriver and observe the position of the slot in the end of the oil pump shaft to make certain it is properly positioned.
  10.  
  11. Replace the screwdriver and, while turning the screwdriver clockwise to guide the oil pump driveshaft gear into engagement with the camshaft gear, press against the oil pump to force it into position.
  12.  
  13. Remove the screwdriver and again observe the position of the slot. If installation was properly made, the slot will be in a position roughly equivalent to the 11 o'clock position on the face of a clock, with the wider side of the slot still on the top. If the slot is improperly positioned, remove the oil pump and repeat the operation.
  14.  
  15. Coat the threads of the capscrews with gasket cement and secure the oil pump in place.
  16.  



Click image to see an enlarged view

Fig. Fig. 1: Oil pump assembly as used on the 4-134 engine

4-150 Engine
  1. Disconnect the battery ground.
  2.  
  3. Raise and support the Jeep on jackstands.
  4.  
  5. Drain the oil.
  6.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

  1. Disconnect the exhaust pipe at the manifold.
  2.  
  3. Remove the starter.
  4.  
  5. Remove the bell housing access plate.
  6.  
  7. Unbolt and remove the oil pan.
  8.  

To install:
  1. Clean the gasket surfaces thoroughly.
  2.  
  3. Install a replacement seal at the bottom of the timing case cover and at the rear bearing cap.
  4.  
  5. Using new gaskets coated with sealer, install the pan and torque the bolts to 10 ft. lbs.
  6.  
  7. Install all other parts in reverse order of removal.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: Oil pump assembly as used on the 4-150, 6-232 and 6-258 engines

4-151 Engine
  1. Drain the oil and remove the oil pan.
  2.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

  1. Remove the oil pump retaining screws and separate the oil pump and gasket from the engine block.
  2.  
  3. Install in reverse order of the above procedure.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Oil pump assembly, 4-151 engine

6-225 Engine
  1. Remove the oil filter.
  2.  
  3. Disconnect the wire from the oil pressure indicator switch in the filter by-pass pump cover assembly to the timing chain cover.
  4.  
  5. Remove the screws that attach the oil pump cover assembly to the timing chain cover.
  6.  
  7. Remove the cover assembly and slide out the oil pump.
  8.  
  9. Install in reverse order of the above procedure.
  10.  

6-232 and 6-258 Engines
  1. Drain the oil and remove the oil pan.
  2.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

  1. Remove the oil pump retaining screws and separate the oil pump and gasket from the engine block.
  2.  

Do not disturb the position of the oil pick-up tube and screen assembly in the pump body. If the tube is moved within the pump body, a new assembly must be installed to assure an airtight seal.

  1. Installation is the reverse of removal. Torque the short bolts to 10 ft. lbs.; the long bolts to 17 ft. lbs.
  2.  

8-304 Engine

The oil pump is attached to the timing cover at its base.

  1. Disconnect the negative battery cable.
  2.  
  3. Rasie and support the vehicle.
  4.  
  5. Drain the engine oil.
  6.  
  7. Remove the pump retaining screws and separate the oil pump cover, gasket and oil filter as an assembly from the pump body (timing chain cover).
  8.  
  9. Clean the pump mounting surface.
  10.  
  11. Install the pump in position using a new gasket. Be sure to install a new oil filter and gasket.
  12.  
  13. Fill the engine to the correct level with oil, run it to normal operating temperature and check for leaks.
  14.  



Click image to see an enlarged view

Fig. Fig. 4: Oil pump assembly used on the 8-304 engine

 
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