Dar,

Nobody needs an engineering degree to post here. Just like any other forum, you have to accept that you might be challenged if you post something. I'm sorry that I put you up to the test. I still don't have any convincing answers to support your view. Not even your own experience saying that you have thousands of hours on an engine into which you put a particular sealed bearing. Others have posted their experience. Seals "seal" to varying degrees. You don't seem to accept the fact that bearings seals are made for various applications and the model engine might be more demanding than it looks to the eye.

Unfortunately, we don't have any bearing manufacturers present here, so I think your demand for answers for the use of the term "seal" will go unanswered.

If you still haven't bothered to verify the fact that NSK offers three different types seals, have a look. Their language is quite clear, that they offer the seals for various applications.

http://www.us.nsk.com/library/catalo...20BEARINGS.PDF