Honda Accord/Civic/Prelude 1973-1983 Repair Guide

Pistons and Connecting Rods

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REMOVAL & INSTALLATION



For removal with the engine out of the vehicle, begin with Step 8.

  1. Remove the turn signals (Civic 1973-77), grille and engine hood.
  2.  
  3. Drain the radiator.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Drain the engine oil.
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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. Raise the front of the vehicle and support it with safety stands.
  2.  
  3. Attach a chain to the clutch cable bracket on the transaxle case or equivalent loacation and raise just enough to take the load off of the center mount.
  4.  

Do not remove the left engine mount.

  1. Remove the center beam and engine lower mount.
  2.  
  3. Remove the cylinder head (see Cylinder Head, Removal & Installation).
  4.  
  5. Loosen the oil pan bolts and remove the oil pan and flywheel dust shield. Loosen the oil pan bolts in a criss-cross pattern beginning with the outside bolt. To remove the oil pan, lightly tap the corners of the oil pan with a mallet.
  6.  


WARNING
Do not pry the oil pan off with the tip of a screwdriver.

  1. Remove the oil passage block and the oil pump assembly.
  2.  


WARNING
As soon as the oil passage block bolts are loosened, the oil in the oil line may flow out.

  1. Working from the underside of the vehicle, remove the connecting rod bearing caps. Using the wooden handle of a hammer, push the pistons and connecting rods out of the cylinders.
  2.  

Before removing the pistons, check the top of the cylinder bore for carbon build-up or a ridge. Remove the carbon or use a ridge reamer to remove the ridge before removing the pistons. Bearing caps, bearings, and pistons should be marked to indicate their location for reassembly.

  1. When removing the piston rings, be sure not to apply excessive force as the rings are made of cast iron and can be easily broken.
  2.  

A hydraulic press is necessary for removing the piston pin. This is a job best left to the professional, if you need to go this far.

To install:
  1. Observe the following points when installing the piston rings:
    1. When installing the three-piece oil ring, first place the spacer and then the rails in position. The spacer and rail gaps must be staggered 20-30mm.
    2.  
    3. Install the second and top rings on the piston with their markings facing upward.
    4.  
    5. After installing all rings on the piston, rotate them to be sure they move smoothly without signs of binding.
    6.  
    7. The ring gaps must be staggered 120° and must NOT be in the direction of the piston pin boss or at right angles to the pin. The gap of the three-piece oil ring refers to that of the middle spacer.
    8.  

  2.  

Pistons and rings are also available in four oversizes, 0.25mm, 0.50mm, 0.75mm, and 1.00mm.

  1. Using a ring compressor, install the piston into the cylinder with the skirt protruding about 1 / 3 of the piston height below the ring compressor. Prior to installation, apply a thin coat of oil to the rings and to the cylinder wall.
  2.  

When installing the piston, the connecting rod oil jet hole or the mark on the piston crown faces the intake manifold.

  1. Using the wooden handle of a hammer, slowly press the piston into the cylinder. Guide the connecting rod so it does not damage the crankshaft journals.
  2.  
  3. Reassemble the remaining components in the reverse order of removal. Install the connecting rod bearing caps so that the recess in the cap and the recess in the rod are on the same side. After tightening the cap bolts (in steps), move the rod back and forth on the journal to check for binding.
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CLEANING AND INSPECTION



  1. Use a piston ring expander and remove the rings from the piston.
  2.  
  3. Clean the ring grooves using an appropriate cleaning tool, exercise care to avoid cutting too deeply.
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  5. Clean all varnish and carbon from the piston with a safe solvent. Do not use a wire brush or caustic solution on the pistons.
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  7. Inspect the pistons for scuffing, scoring, cracks, pitting or excessive ring groove wear. If wear is evident, the piston must be replaced.
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  9. Have the piston and connecting rod assembly checked by a machine shop for correct alignment, piston pin wear and piston diameter. If the piston has collapsed it will have to be replace or knurled to restore original diameter. Connecting rod bushing replacement, piston pin fitting and piston changing can be handled by the machine shop.
  10.  

CYLINDER BORE



Check the cylinder bore for wear using a telescope gauge and a micrometer, measure the cylinder bore diameter perpendicular to the piston pin at a point 63.5mm below the top of the engine block. Measure the piston skirt perpendicular to the piston pin. The difference between the two measurements is the piston clearance. If the clearance is within specifications, finish honing or glaze breaking is all that is required. If clearance is excessive a slightly oversize piston may be required. If greatly oversize, the engine will have to be bored and 0.25mm or larger oversized pistons installed.

FITTING AND POSITIONING PISTON RINGS



  1. Take the new piston rings and compress them, one at a time into the cylinder that they will be used in. Press the ring about 25mm below the top of the cylinder block using an inverted piston.
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  3. Use a feeler gauge and measure the distance between the ends of the ring. This is called measuring the ring end gap. Compare the reading to the one called for in the specifications table. File the ends of the ring with a fine file to obtain necessary clearance.
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If inadequate ring end gap is utilized, ring breakage will result.

  1. Inspect the ring grooves on the piston for excessive wear or taper. If necessary have the grooves recut for use with a standard ring and spacer. The machine shop can handle the job for you.
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  3. Check the ring grooves by rolling the new piston ring around the groove to check for burrs or carbon deposits. If any are found, remove with a fine file. Hold the ring in the groove and measure side clearance with a feeler gauge. If clearance is excessive, spacer(s) will have to be added.
  4.  

Always add spacers above the piston ring.

  1. Install the ring on the piston, lower oil ring first. Use a ring installing tool on the compression rings. Consult the instruction sheet that comes with the rings to be sure they are installed with the correct side up. A mark on the ring usually faces upward.
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  3. When installing oil rings, first, install the expanding ring in the groove. Hold the ends of the ring butted together (they must not overlap) and install the bottom rail (scraper) with the end about 25mm away from the butted end of the control ring. Install the top rail about 25mm away from the butted end of the control but on the opposite side from the lower rail.
  4.  
  5. Install the two compression rings.
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  7. Install a ring compressor and insert the piston and rod assembly into the engine.
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