Valve Guide Measurement

WARNING: This page is about a different variant/trim than selected.

Fig 1: Inspecting For Excessive Valve Stem To Guide Clearance

Courtesy of GENERAL MOTORS COMPANY

Measure the valve stem (1) to guide (2) clearance. Excessive valve stem to guide clearance may cause an excessive oil consumption and may also cause a valve to break. Insufficient clearance will result in noisy and sticky functioning of the valve and will disturb the engine assembly smoothness.
Clamp the GE 7872 dial indicator to the cylinder head at the camshaft cover rail.
Locate the dial indicator so that the movement of the valve stem from side to side, crossways to the cylinder head, will cause a direct movement of the indicator stem. The dial indicator stem must contact the side of the valve stem just above the valve guide.
Drop the valve head about 0.064 mm (0.0025 in) off the valve seat.
Use light pressure when moving the valve stem from side to side in order to obtain a clearance reading. Refer to Engine Mechanical Specifications (LEA, or LUK) for proper clearance.

NOTE:

Valve guide wear at the bottom 10 mm (0.390 in) of the valve guide is not significant to normal operation.

If the clearance for the valve is greater than specifications and a new standard diameter valve stem will not bring the clearance within specifications, replace the cylinder head.