Cylinder Head Measurement

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora and 2001 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Refer to FASTENER NOTICE in Cautions and Notices.

Measure the camshaft clearance specification using the following procedure:
1. 1.1. Install the camshaft caps.
2. 1.2. Install the camshaft caps bolts.
  Tighten
  
  Tighten the camshaft bearing caps bolts to 5 N.m (44 in lbs).
3. 1.3. Measure the camshaft bearings using an inside micrometer.
4. 1.4. Inspect and measure the camshaft journal diameters. Refer to Camshaft Cleaning and Inspection .
5. 1.5. Subtract the camshaft journal diameter from the camshaft bearing diameter in order to obtain the running clearance.
6. 1.6. If the running clearance exceeds the specifications and the camshaft journals are within specification, replace the cylinder head. Refer to Engine Mechanical Specifications .
Measure the camshaft thrust specification using the following procedure:
1. 2.1. Inspect each camshaft cap thrust surface for excessive scoring/wear.
2. 2.2. Inspect each camshaft. Refer to Camshaft Cleaning and Inspection .
3. 2.3. Install the intake and exhaust camshafts in the cylinder head.
4. 2.4. Install the camshaft caps.
5. 2.5. Install the camshaft caps bolts.
  Tighten
  
  Tighten the camshaft bearing caps bolts to 5 N.m (44 in lbs).
6. 2.6. Measure the camshaft thrust bearing clearance at the front camshaft bearing cap. Refer to Engine Mechanical Specifications .
7. 2.7. If the camshaft thrust bearing clearance is not to specification repair or replace the cylinder head.
Measure the cylinder head flatness using the following procedure:
1. 3.1. Clean any remaining head gasket material from the cylinder head face.
2. 3.2. Place a straight-edge diagonally across the cylinder head face surface.
3. 3.3. Measure the clearance between the straight-edge and the cylinder head using a feeler gage at four points along the straight-edge.
  - If warpage is less than 0.05 mm (0.002 in), the cylinder head surface does not require resurfacing.
  - If warpage is between 0.05-0.20 mm (0.002-0.008 in), the cylinder head must be resurfaced.

Fig 1: Measuring Cylinder Head Flatness

Courtesy of GENERAL MOTORS CORP.

If resurfacing is required, the dimension between the combustion chamber gage pad and the deck surface (1) must be at least 10.5 mm (0.413 in).

Fig 2: Measuring Dimension Between Combustion Chamber Gage Pad & Deck Surface
Courtesy of GENERAL MOTORS CORP.