Which symptom besides oil consumption indicates excessive ring and/or cylinder wear?

When analyzing symptoms of excessive ring and cylinder wear, the presence of pressure in the crankcase is a significant indicator. This condition often occurs due to the loss of compression within the cylinders, which allows combustion gases to escape into the crankcase. As wear increases, the sealing capabilities of the rings diminish, resulting in higher crankcase pressure.

Good engine design usually minimizes crankcase pressure, so when it rises, it suggests that the engine suffers from compromised sealing, which is often a direct consequence of ring and cylinder wear. This pressure can also lead to other issues, such as oil leaks or increased oil aeration, which further complicate engine performance.

Understanding this concept helps in diagnosing engine health effectively, particularly in four-stroke engines, where maintaining proper seal integrity is crucial for optimal operation. Other symptoms, while they can suggest issues in an engine, do not directly point to excessive wear in the rings or cylinders. For example, an extremely clean intake tract may be indicative of an efficient air-fuel mixture but does not necessarily signify the condition of the rings or cylinders.