When performing a wet compression test, what should be the expected result if piston rings are faulty?

In a wet compression test, a small amount of oil is added to the cylinders before taking the measurements. This oil helps to temporarily seal any gaps caused by worn piston rings or poor cylinder sealing. When piston rings are faulty or worn, they fail to maintain proper compression, leading to lower compression readings in a dry test.

If the piston rings are indeed the issue, adding oil during a wet compression test typically results in higher compression readings. This occurs because the oil provides a temporary seal, allowing the combustion chamber to hold more pressure. Consequently, if the piston rings are the culprit, you would expect the readings from the wet test to be significantly higher than the dry test results, reflecting the improvement due to the sealing effect of the oil.

Saying that the compression readings should equal the dry test results does not align with the expected outcomes of a wet compression test when piston rings are faulty, as the intent of the wet test is to evaluate the sealing capability of the piston rings and cylinder walls.

In summary, a significant increase in compression readings during a wet test compared to a dry test indicates that the piston rings are likely allowing compression to escape when dry, validating the effectiveness of the wet test in diagnosing faults with the piston rings.