Valve Guide Reaming/Valve and Seat Grinding

Valve Guide Reaming
Tools Required

J 37378-1 Valve Guide Reamer

    Object Number: 65822  Size: SH


  1. Measure the valve stem-to-guide clearance using a dial indicator. Valve stem-to-guide clearance may also be obtained by using a micrometer to measure the valve stem diameter and a ball type measuring gage to measure the guide bore.
    Object Number: 156172  Size: SH

  2. A valve stem (1) and guide (2) with clearance in excess of 0.093 mm (0.0037 in) must be repaired or the components replaced.
    Object Number: 156174  Size: SH

  3. Inspect the valve stems for excessive scoring, wear, or warpage.
  4. Measure the valve stem diameter. A valve stem with a diameter less than 7.95 mm (0.313 in) must be replaced. Position the tip of the dial indicator at the top of the valve guide. If the valve stem diameter is within specifications, and the stem-to-guide clearance is excessive, the valve guide must be reamed oversize and a valve with oversize stem installed.
    Object Number: 572270  Size: SH

  5. Ream the valve guide using the J 37378-1 .
  6. Clean the guide bore of all metal shavings and debris.
    Object Number: 1272857  Size: SH

  7. Install the valve (227 and 228), with oversize stem, into the cylinder head (218).
  8. Inspect the valve for proper fit. Move the valve back and forth in the guide. The valve should move freely with no resistance or drag.
Valve and Seat Grinding

    Object Number: 156174  Size: SH


  1. Inspect the valve for the following conditions:
    Object Number: 156173  Size: SH

  2. Inspect the valve face for the following conditions:
    Object Number: 4955  Size: SH

  3. Inspect the valve margin. The exhaust valve may be refaced if the margin is greater than 1.25 mm (0.05 in) thick before grinding.
  4. Reface pitted exhaust valves on a suitable valve refacing machine.
  5. Replace the valve if the margin is less than 1.25 mm (0.05 in) thick after grinding.
  6. If the valve face has been ground, it may be necessary to shim the valve spring to obtain the proper spring installed height. Refer to Cylinder Head Assemble .
    Object Number: 1272854  Size: MH

  7. Inspect for a loose valve seat in the cylinder head (218). The valve seat has an interference fit to the cylinder head.
  8. Clean the valve guide bores with a suitable tool. Remove all carbon or dirt from the bores. The valve guide must be clean for the seat grinding tool to obtain proper results.
  9. Grind the valve seat. The recommendations of the manufacturer of the equipment should be followed carefully to obtain the proper results. Regardless of what type of equipment is used, it is essential that valve guide bores be free from carbon or dirt to ensure proper centering of the tool pilot in the guide.
  10. Inspect the valve seats.