I'm in the process of rebuilding a 12A NA engine and have found that the rear oil seal (located in the rear stationary gear) can be rotated in its housing. The engine has only done 80k miles and is in good order otherwise. I have a spare engine and the rear seal in it can be rotated in the same way.

While I say the seal can be rotated it does not rotate freely but rather can be turned with your fingers and is not loose in the housing. I haven't ever seen a seal in this type of application able to be rotated.

Is this a common occurrence with rotary engines and if so is it only because of age or use? Is the new seal when fitted likely to be able to be rotated in the same way or should I expect it to be tight in its housing?

The overhaul manual quite specifically states not to use any sealing agent on this seal. Has anyone experienced this type of issue?

Any input will be appreciated.

 

I've never seen it. What color are they? The orange ones are softer than the earlier black type.

I recently pulled an engine that had a leaky rear seal. It was otherwise in great shape internally, but it smoked a bit on startup. It seems the rubber seals are aged but the hard seals are nice. Apex seals measure 7.89mm.

 

I have seen this a number of times and the seal was not leaking. After installing a new seal it no longer was loose.