Honda Accord/Civic/Prelude 1973-1983 Repair Guide

Crankshaft and Main Bearings

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REMOVAL & INSTALLATION



  1. Remove the engine from the vehicle and place it on a work stand.
  2.  
  3. Remove the crankshaft pulley attaching bolts and washer.
  4.  
  5. Remove the front cover and the air conditioning idler pulley assembly, if so equipped. Remove cover assembly.
  6.  
  7. Check the timing belt deflection. Remove the timing belt and sprockets.
  8.  
  9. Invert the engine on work stand. Remove the flywheel and the rear seal cover. Remove the oil pan and gasket. Remove the oil pump inlet and the oil pump assembly.
  10.  
  11. Ensure all bearing caps (main and connecting rod) are marked so they can be installed in their original positions. Turn the crankshaft until the connecting rod from which cap is being removed is up. Remove the connecting rod cap. Push the connecting rod and piston assembly up in the cylinder. Repeat the procedure for the remaining connecting rod assemblies.
  12.  
  13. Remove the main bearing caps.
  14.  
  15. Carefully lift crankshaft out of block so upper thrust bearing surfaces are not damaged.
  16.  


WARNING
Handle the crankshaft with care to avoid possible fracture or damage to the finished surfaces.

If the bearings are to be reused they should be identified to ensure that they are installed in their original position.

  1. Remove the main bearing inserts from the block and bearing caps.
  2.  
  3. Remove the connecting rod bearing inserts from connecting rods and caps.
  4.  

To install:
  1. Install a new rear oil seal in rear seal cover.
  2.  
  3. Apply a thin coat of Polyethylene Grease to the rear crankshaft surface. Do not apply sealer to the area forward of oil sealer groove. Inspect all the machined surfaces on the crankshaft for nicks, scratches or scores which could cause premature bearing wear.
  4.  
  5. If the crankshaft main bearing journals have been refinished to a definite undersize, install the correct undersize bearings. Ensure the bearing inserts and bearing bores are clean. Foreign material under the inserts will distort the bearing and cause a failure.
  6.  
  7. Place the upper main bearing inserts in position in the bores with the tang fitted in the slot provided.
  8.  
  9. Install the lower main bearings inserts in the bearing caps.
  10.  
  11. Carefully lower the crankshaft into place.
  12.  
  13. Check the clearance of each main bearing. Select fit the bearings for proper clearance.
  14.  
  15. After the bearings have been fitted, apply a light coat of heavy engine oil, SAE 50 weight to journals and bearings. Install all the bearing caps.
  16.  

The main bearing cap must be installed in their original positions.

  1. Align the upper thrust bearing.
  2.  
  3. Check the crankshaft end-play.
  4.  
  5. If the end-play exceeds specification, replace the upper thrust bearing. If the end-play is less than the specification, inspect the thrust bearing faces for damage, dirt or improper alignment. Install the thrust bearing and align the faces. Check the end-play.
  6.  
  7. Install the new bearing inserts in the connecting rods and caps. Check the clearance of each bearing.
  8.  
  9. If the bearing clearances are to specification, apply a light coat of heavy engine oil, SAE 50 weight to the journals and bearings.
  10.  
  11. Turn the crankshaft throw to the bottom of the stroke. Push the piston all the way down until the rod bearings seat on the crankshaft journal.
  12.  
  13. Install the connecting rod cap.
  14.  
  15. After the piston and connecting rod assemblies have been installed, check the connecting rod crankshaft journal.
  16.  
  17. Turn the engine on the work stand so the front end is up. Install the timing belt, sprockets, front cover, oil seal and the crankshaft pulley.
  18.  
  19. Clean the oil pan, oil pump and the oil pump screen assembly.
  20.  
  21. Prime the oil pump by filling the inlet opening with oil and rotating the pump shaft until oil emerges from the outlet opening. Install the oil pump.
  22.  
  23. Position the flywheel or flexplate on the crankshaft. Install the attaching bolts. Tighten to specification.
  24.  

On the flywheel (manual transaxle only) locate clutch disc and install pressure plate.

  1. Turn the engine on the work stand so the engine is in the normal upright position. Install the oil level dipstick. Install the accessory drive pulley, if so equipped. Install and adjust the drive belt and the accessory belts to specification.
  2.  
  3. Install either the clutch assembly or the torque converter.
  4.  
  5. Install the oil pan.
  6.  
  7. Remove the engine from work stand. Install the engine in the vehicle.
  8.  

BEARING OIL CLEARANCE INSPECTION



See Figures 1, 2 and 3

Remove cap from the bearing to be checked. Using a clean, dry rag, thoroughly clean all oil from crankshaft journal and bearing insert.

Plastigage® is soluble in oil, therefore, oil on the journal or bearing could result in erroneous readings.

Place a pieced of Plastigage® along the full width of the bearing insert, reinstall cap, and torque to specifications.

Specifications are given in the engine specifications earlier in this section.

Remove bearing cap, and determine bearing clearance by comparing width of Plastigage® to the scale on Plastigage® envelope. Journal taper is determined by comparing width of the bearing insert, reinstall cap, and torque to specifications.



Click image to see an enlarged view

Fig. Fig. 1: Plastigage® installed on lower bearing shell



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Fig. Fig. 2: Measure Plastigage® to determine bearing clearance



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Fig. Fig. 3: View of Plastigage® on crankshaft

Do not rotate crankshaft with Plastigage® installed. If bearing insert and journal appear intact, and are within tolerances, no further main bearing service is required. If bearing or journal appear defective, cause of failure should be determined before replacement.

CRANKSHAFT ENDPLAY/CONNECTING ROD SIDE PLAY



See Figures 4 and 5

Place a pry bar between a main bearing cap and crankshaft casting taking care not to damage any journals. Pry backward and forward, measure the distance between the thrust bearing and crankshaft with a feeler gauge. Compare reading with specifications. If too great a clearance is determined, a main bearing with a larger thrust surface or crank machining may be required. Check with an automotive machine shop for their advice.



Click image to see an enlarged view

Fig. Fig. 4: Check the connecting rod side clearance with feeler gauge



Click image to see an enlarged view

Fig. Fig. 5: Check the crankshaft end-play with a dial indicator

Connecting rod clearance between the rod and crankthrow casting can be checked with a feeler gauge. Pry the rod carefully on one side as far as possible and measure the distance on the other side of the rod.

CRANKSHAFT REPAIRS



If a journal is damaged on the crankshaft, repair is possible by having the crankshaft machined to a standard undersize.

In most cases, however, since the engine must be removed from the car and disassembled, some thought should be given to replacing the damaged crankshaft with a reground shaft kit. A reground crankshaft kit contains the necessary main and rod bearings for installation. The shaft has been ground and polished to undersize specifications and will usually hold up well if installed correctly.

 
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