Chevrolet Blazer/Jimmy 1969-1982 Repair Guide

Valve Stem Seals

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REMOVAL & INSTALLATION



Cylinder Head Removed


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Fig. Fig. 1 With the valve spring out of the way, the valve stem seals may now be replaced



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Fig. Fig. 2 Instal the valve stem seal before installing the spring

  1. Remove the head(s), and place on a clean surface.
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  3. Using a suitable spring compressor, compress the valve spring and remove the valve spring cap key. Release the spring compressor and remove the valve spring and cap (and valve rotator on some engines).
  4.  

Use care in removing the keys. They are easily lost.

  1. Remove the valve seals from the intake valve guides. Throw these old seals away, as you'll be installing new seals during reassembly.
  2.  

New valve seals must be installed when the valve train is put back together. Certain seals slip over the valve stem and guide boss, while others require that the boss be machined. Teflon® guide seals are available. Check with a machinist and/or automotive parts store for a suggestion on the proper seals to use.

Remember that when installing valve seals, a small amount of oil must be able to pass the seal to lubricate the valve guides; otherwise, excessive wear will result.

To install:

  1. Lubricate the valve stems with clean engine oil.
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  3. Lubricate and position the seals and valve springs, again a valve at a time.
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  5. Install the spring retainers, and compress the springs.
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  7. With the valve key groove exposed above the compressed valve spring, wipe some wheel bearing grease around the groove. This will retain the keys as you release the spring compressor.
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  9. Using needlenose pliers (or your fingers), place the keys in the key grooves. The grease should hold the keys in place. Slowly release the spring compressor. The valve cap or rotator will raise up as the compressor is released, retaining the keys.
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  11. Install the rocker assembly, and install the cylinder head(s)
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Cylinder Head Installed


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Fig. Fig. 3 Compressing the valve springs with the head installed

Special tool J-23590, or its equivalent air line adaptor, will be necessary for this job.

If is often not necessary to remove the cylinder head(s) in order to service the valve train. Such is the case when valve seals need to be replaced. Valve seals can be easily replaced with the head(s) on the engine. The only special equipment needed for this job are an air line adapter (sold in most auto parts stores), which screws a compressed air line into the spark plug hole of the cylinder on which you are working, and a valve spring compressor. A source of compressed air is needed, of course.

  1. Remove the cylinder head cover.
  2.  
  3. Remove the spark plug, rocker arm and pushrod on the cylinder(s) to be serviced.
  4.  
  5. Position the engine so that both valves are closed.
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  7. Install air line adapter into the spark plug hole. Turn on the air compressor to apply compressed air into the cylinder. This keeps the valves up in place.
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Set the regulator of the air compressor at least 50 psi (344 kPa) to ensure adequate pressure.

  1. Using the valve spring compressor, compress the valve spring and remove the valve keys and keepers, the valve spring and damper.
  2.  
  3. Remove the valve stem seal.
  4.  
  5. To reassemble, oil the valve stem and new seal. Install a new seal over the valve stem. Set the spring, damper and keeper in place. Compress the spring. Coat the keys with grease to hold them onto the valve stem and install the keys, making sure they are seated fully in the keeper. Reinstall the cylinder head cover after adjusting the valves, as outlined in this section.
  6.  

 
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