Finally got around to installing the new o-ring on Smaug's CAS today. Marked the position, pulled the CAS, removed the cover, cleaned minor surface rust off the disk (no abrasives, just a little brasso wadding followed by a thorough polish). Pin and springs are intact and clean. A little more clean and polish on the CAS body, a bit of plastic polish on the cover, then reinstalled. Reseating the CAS seems to have removed the tiny play in the disk that was there when I removed it.
Paper clip, base timing double-checked @ 16 BTDC. A nice little project for the afternoon.
And yes, Specky, I did
polish the retaining bolt and washers.