How can excessive camshaft lobe wear be determined without removing the cam from the engine?

A. Use a micrometer to measure each lobe.
B. Remove the rocker cover and measure the push rod travel on each cylinder.
C. Remove the timing cover and use a dial indicator on the end of the cam.
D. Remove the rocker cover and insert a feeler gauge between the valve stem and the rocker arm.

Excessive camshaft lobe wear can be determined by removing the rocker cover and using a feeler gauge to measure the clearance between the valve stem and rocker arm, comparing it with the manufacturer's specifications.

Explanation:

To determine excessive camshaft lobe wear without removing the cam from the engine, the following method can be used: Remove the rocker cover and insert a feeler gauge between the valve stem and the rocker arm. This allows you to measure the valve clearance. Valve clearances that are excessive can indicate that the cam lobes have worn down, as the distance the follower has to travel to contact the valve increases.

This procedure does not require removal of the camshaft and can be a relatively quick way to assess lobe wear, provided the engine's design allows easy access to the valve train for inspection. It's important to note that each engine has its specific clearance specifications provided by the manufacturer, and these should be checked against the measured values.