What could be used to identify worn or defective valves?

Using a combination of methods such as a visual inspection, compression test, and leak-down test is crucial in identifying worn or defective valves. Each method provides valuable insights into the valves' condition.

A visual inspection can reveal obvious signs of wear, damage, or carbon buildup on the valves that may not function properly. It gives an initial indication of the valves' physical state and can help identify issues that need further investigation.

A compression test measures the pressure within the cylinder when the engine is cranked, which can indicate how well the valves are sealing. Low compression can be attributed to problems with the valves, such as not closing properly due to wear or damage.

A leak-down test further evaluates the valves and allows for diagnosing specific issues by measuring how much air escapes from the cylinder when it is pressurized. This test can pinpoint whether the air loss is due to worn valves, seals, or other associated components.

Together, these methods create a comprehensive assessment approach, improving the chances of accurately identifying worn or defective valves. Hence, using all of the above methods provides the most reliable diagnosis.