Jeep CJ 1945-1970 Repair Information

Crankshaft

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REMOVAL



4-134 Engines
  1. Remove the engine from the vehicle.
  2.  
  3. Remove the fan, hub, timing cover, pulleys and timing gears from the engine.
  4.  
  5. Slide the thrust washers and adjusting shims from the front end of the crankshaft. Be careful to avoid losing or mismatching the washers and shims!
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  7. Remove the oil pan and pick-up.
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  9. Pull the two pieces of the rear main cap packing out from the sides of the cap.
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  11. Note the matchmarks on the bearing caps and remove the nuts and washers from the cap dowels.
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  13. Using a prybar under the ends of each main cap, carefully lift the caps off the dowels. Take great care to avoid damage to the caps or dowels, as bent dowels must be replaced.
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  15. Note the matchmarks on the connecting rod caps and remove the bearing caps from the rods.
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  17. Lift the crankshaft from the block.
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6-225 Engine
  1. Remove the engine and mount it on a work stand.
  2.  
  3. Remove the flywheel.
  4.  
  5. Remove the fan and hub.
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  7. Remove the crankshaft pulley and vibration damper.
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  9. Remove the timing chain and sprocket.
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  11. Remove the oil pan, and pick-up.
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  13. Remove the connecting rod caps, marking them for reassembly.
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  15. Mark the main bearing caps.
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  17. Remove the two bolts from the cap and carefully lift it off with the aid of a prybar. Similarly remove the next two caps.
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  19. To remove the last cap, a special tool, main bearing bolt remover W-323 is necessary.
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  21. Lift the crankshaft from the block.
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INSPECTION



  1. Check the crankshaft for wear or damage to the bearing surfaces of the journals. Crankshafts that are damaged can be reconditioned by a professional machine shop.
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  3. Using a dial indicator, check the crankshaft journal run-out. Measure the crankshaft journals with a micrometer to determine the correct size rod and main bearings to be used. Whenever a new or reconditioned crankshaft is installed, new connecting rod bearings and main bearings should be installed.
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  5. Clean all oil passages in the block (and crankshaft if it is being reused).
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A new rear main seal should be installed any time the crankshaft is removed or replaced.

  1. Wipe the oil from the crankshaft journal and the outer and inner surfaces of the bearing shell.
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  3. Place a piece of plastic gauging material in the center of the bearing.
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  5. Use a floor jack or other means to hold the crankshaft against the upper bearing shell. This is necessary to obtain accurate clearance readings when using plastic gauging material.
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  7. Install the bearing cap and bearing. Place engine oil on the cap bolts and install. Tighten the bolts to specification.
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  9. Remove the bearing cap and determine the bearing clearance by comparing the width of the flattened plastic gauging material at its widest point with the graduations on the gauging material container. The number within the graduation on the envelope indicates the clearance in millimeters or thousandths of an inch. If the clearance is greater than allowed, replace both bearing shells as a set . Recheck the clearance after replacing the shells.
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INSTALLATION

Main bearing clearances must be corrected by the use of selective upper and lower shells. UNDER NO CIRCUMSTANCES should the use of shims behind the shells to compensate for wear be attempted.

  1. Install new bearing upper halves in the block. If the crankshaft has been turned to resurface the journals, undersized bearing must be used to compensate. Lay the crankshaft in the block.
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  3. Install the lower bearing halves in the caps.
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  5. Use Plastigage® to check bearing fit.
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  7. When the bearings are properly fitted, install and tighten the bearing caps.
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  9. Check crankshaft end-play to determine the need for thrust washers.
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  11. While you're at it, it's a good idea to replace the rear main seal at this time.
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  13. Install sufficient oil pan bolts in the block to align with the connecting rod bolts. Use rubber bands between the bolts to position the connecting rods as required. Connecting rod position can be adjusted by increasing the tension on the rubber bands with additional turns around the pan bolts or thread protectors.
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  15. Position the upper half of main bearings in the block and lubricate them with engine oil.
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  17. Position crankshaft key way in the same position as removed and lower it into block. The connecting rods will follow the crank pins into the correct position as the crankshaft is lowered.
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  19. Lubricate the thrust flanges with clean engine oil or engine rebuilding oil. Install caps with the lower half of the bearings lubricated with engine oil. Lubricate the cap bolts with engine oil and install, but do not tighten.
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  21. With a block of wood, bump the shaft in each direction to align the thrust flanges of the main bearing. After bumping the shaft in each direction, wedge the shaft to the front and hold it while torquing the thrust bearing cap bolts.
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In order to prevent the possibility of cylinder block and/or main bearing cap damage, the main bearing caps are to be tapped into their cylinder block cavity using a wood or rubber mallet before the bolts are installed. Do not use attaching bolts to pull the main bearing caps into their seats. Failure to observe this information may damage the cylinder block or a bearing cap.

  1. Tighten all main bearing caps to specification. Check crankshaft end-play, using a flat feeler gauge.
  2.  
  3. Remove the connecting rod bolt thread protectors and lubricate the connecting rod bearings with engine oil.
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  5. Install the connecting rod bearing caps in their original position. Tighten the nuts to specification.
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  7. Install all parts in reverse order of removal. See related procedures in this section for component installation.
  8.  

 
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