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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 722 (Engine Mechanical - 8.1L (Unit Repair)) >> Repair Instructions >> Valve Guide Reaming/Valve and Seat Grinding >> Valve Seat Reconditioning Procedure

Valve Seat Reconditioning Procedure

WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Important:  Several different types of equipment are available for reconditioning valve seats. Use the manufacturers recommendations of equipment to attain the proper results.

Important:  Always recondition the valve seat after reaming the valve guide bores or installing new valves.

  1. Recondition the valve seats.
  2. The valves must seat perfectly for the engine to deliver optimum power and performance.
  3. Ensure that the valve seat and valve are not shrouded after valve seat reconditioning. Adequate flow past the valve seat and valve is essential for cooling the valve head and valve seat area.
  4. Correct contact (1) between each valve and its seat in the cylinder head is also essential to ensure that the heat in the valve head is properly carried away.

    Important:  Regardless of what type of equipment is used, it is essential that the valve guide bores are free from carbon or dirt to ensure the proper centering of the pilot in the guide.

  5. The valve seats should be concentric to within 0.050 mm (0.002 in) total indicator runout.
    Fig 1: Valve Seat Measurements
    G01675488Courtesy of GENERAL MOTORS CORP.