Measure • Ring clearance. Use a feeler gage and compare with “Specifications”. Camshaft Figures 12-41 and 12-42 Tool Required: J 7872 Dial Indicator or Equivalent IMPORTANT: Do not attempt to repair the camshaft, replace it if damaged. Whenever the camshaft is replaced, a new set of lifters must also be installed. Inspect • Bearing surfaces and lobes for wear. • Sprockets. • Keyway and threads for galling, gouges, or overheating. • Camshaft journal diameters (figure 12-41). Refer to “Engine Specifications” for proper diameters. • Camshaft runout (figure 12-42). Mount the camshaft in V-blocks or between centers. Using J 7872, check the intermediate camshaft journal.
Compare camshaft runout with “Specifications”. If the camshaft is excessively bent, replace the camshaft and camshaft bearings. Figure 12-39 Measuring Ring-to-Land Clearance Intake and Exhaust Manifolds Figure 12-40 Clean • Mating surfaces on intake manifold and cylinder head. • Excessive carbon buildup in the exhaust passages of the intake manifold. • Scale and deposits from the coolant passages of the intake manifold. • EGR passage of excessive carbon deposits. Inspect • Manifolds for cracks, broken flanges, and gasket surface damage. • Alignment of manifold flanges. Use a straightedge and feeler gage. If the flanges do not align, the manifold is warped and should be replaced.
Figure 12-41 Measuring Camshaft Journals Figure 12-40 Checking Manifold Flange Alignment Figure 12-42 Measuring Camshaft Runout G643 (E) Service Manual Chapter 3. Engine Mechanical System 80