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

Measuring the push rod travel on each cylinder is an effective method to determine excessive camshaft lobe wear without needing to remove the cam from the engine. When cam lobes wear down, they alter the lift of the valves. This change in lift can subsequently affect how far the push rods travel during operation. If the push rod travel is inconsistent or less than expected, it can indicate that the camshaft lobes have worn significantly, resulting in reduced performance.

Other options, while they may provide useful information, do not directly assess the condition of the camshaft lobes. For instance, checking for oil leaks or listening for abnormal engine noise might indicate broader issues in the engine but wouldn't specifically highlight camshaft lobe wear. Inspecting the camshaft for visible damage, though insightful, requires removal of the cam from the engine which is contrary to the premise of the question. Therefore, measuring push rod travel offers a non-invasive and practical approach to assess camshaft condition effectively.