Pontiac Fiero 1984-1988 Repair Guide

Crankshaft

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REMOVAL




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 engine assembly as previously outlined in the Engine removal procedures.
  2.  
  3. Remove the engine timing chain or gear front cover.
  4.  
  5. Remove the timing chain and sprockets (6 cylinder).
  6.  
  7. Remove the oil pan as outlined in the Oil Pan removal procedures.
  8.  
  9. Remove the oil pump, (remove the force balancer assembly on the 1987-88 2.5L L4 engine).
  10.  
  11. Stamp the cylinder number on the machined surfaces of the bolt boses of the connecting rods and caps for identification when installing. If the pistons are to be removed from the connecting rod, mark the cylinder number on each piston with an indelible marker, silver pencil or quick drying paint for proper cylinder identification and cap to rod location.
  12.  
  13. Remove the connecting rod caps and store them so that they can be installed in their original positions.
  14.  
  15. Mark and remove all the main bearing caps.
  16.  
  17. Note the position of the keyway in the crankshaft so it can be installed in the same position.
  18.  
  19. With an assistant, lift the crankshaft out of the block. The rods will pivot to the center of the engine when the crankshaft is removed.
  20.  
  21. Remove both halves of the rear main oil seal.
  22.  

INSPECTION & INSTALLATION





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Fig. Fig. 1 Align the crankshaft thrust flanges of the main bearing (1) by bumping the crankshaft in each direction using a block of wood (2)



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Fig. Fig. 2 A dial gauge may be used to check crankshaft end-play



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Fig. Fig. 3 Carefully pry the shaft back and forth while reading the dial gauge for play



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Fig. Fig. 4 A dial gauge may also be used to check crankshaft run-out



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Fig. Fig. 5 Turn the crankshaft slowly by hand while checking the gauge



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Fig. Fig. 6 Mounting a dial gauge to read crankshaft run-out

  1. 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 must be installed. The bearing undersize are usually 0.010, 0.020 and 0.030 inch. Do not go any further undersize than 0.030 inch. See Main Bearings and Rod Bearings in the beginning of this section.
  2.  
  3. Clean all oil passages in the block (and crankshaft if it is being reused).
  4.  

A new rear main seal should be installed anytime the crankshaft is removed or replaced.

  1. 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. Install if not already done, pieces of rubber hose on the connecting rod bolts to protect the crankshaft journals during installation.
  2.  
  3. Position the upper half of main bearings in the block and lubricate them with Assembly Lube.
  4.  
  5. Position crankshaft keyway in the same position as removed, with an assistant, lower the crankshaft into the block. The connecting rods will follow the crank pins into the correct position as the crankshaft is lowered.
  6.  
  7. Lubricate the thrust flanges with Assembly Lube 10501609 or equivalent. Install rod caps with the lower half of the bearings lubricated with Assembly Lube. Lubricate the cap bolts with Assembly Lube and install, but do not tighten.
  8.  
  9. With a block of wood, bump the crankshaft 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.
  10.  

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. Torque all main bearing caps to specification in the Torque Specifications chart in this section.
  2.  
  3. Remove the connecting rod bolt thread protectors and lubricate the connecting rod bearings with Assembly Lube.
  4.  
  5. Install the connecting rod bearing caps in their original position. Torque the nuts to specifications in the Torque Specifications chart in this section.
  6.  
  7. Install the oil pump, oil pan, timing cover, accessories and install the engine assembly into the vehicle as outlined in the Engine installation procedures.
  8.  

 
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