GM 6.5L V8 – Camshaft Lobe Lift Check

1. Remove the rocker arm cover and rocker arm shaft assemblies for the cylinders to be checked.
2. Rotate the crankshaft so that one push rod for the cylinder being checked is at its minimum height (valve closed).
3. Install a dial indicator so that its button rests on the top of the push rod for the first valve of the cylinder being checked (see Figure 2-40, view A).
4. Make sure that the dial indicator stem is parallel to the push rod and that the indicator needle points to zero.
5. Rotate the crankshaft until the push rod is at its maximum height (valve fully open).
6. Observe the amount of dial indicator travel (see Figure 2-40, view B):
• If travel is more than 7.063 mm (0.278 in.), see step 7.
• If travel is less than 7.063 mm (0.278 in.), replace the camshaft and lifters.
7. Perform steps 2 through 6 for the other valve for the cylinder being checked.
8. When all cylinders are checked, remove the dial indicator and install the rocker arm shaft assemblies and rocker arm covers (if repairs are not required).

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