MGB A bellhousing mystery....

Some call Scooby and the gang because I found a real mystery in my MGB.... I got (with much help) the engine/transmission out of the 1970 B that is well past my skill level to save. Before installing it into the 1973 body, it makes sense to do the clutch and release bearing while it is sitting on the castor pallet with everything easily accessible. So I removed the starter, pulled all the bolts for the bellhousing with the transmission supported on a rolling jack and started sliding the transmission back from the engine, and as soon as I had about 1/2 inch gap between them something fell out. I finished getting them apart (the input shaft was really stiff trying to get it out from the clutch) and everything looks intact, but I have this extra mystery thing that fell out. It is a metal disk about the size of a Kennedy half dollar, thickness of a fender washer. Possibly stainless steel based on appearance/lack of corrosion/weight. It has a approx 3/8 inch hole in the center, and 3 very fine (1/64 or even less) holes about 1/16th in from the edge - 1 at each 120 degree interval around the circumference. There were also some bits of what could have been a rubber seal, but based on the curve of them they were too small to have been remnants of an engine oil seal or transmission shaft seal. Plus there was no oil on the flywheel or backplate of the engine. It is somewhat worn around the edge, so it probably had been loose in there when the engine was last run almost a decade ago. It seems too large to have fallen out of the clutch (it doesn't fit through any of the gaps) but I have not yet pulled the clutch off the flywheel (that is next weekend). All the bolts and fittings inside the bellhousing on the transmission are present and accounted for, the hole in the mystery part is too small for it to have been anything that went on the main shaft itself. I don't intend to pull the flywheel from the engine, and I can't see anyplace where this could have come from on the engine side behind the flywheel. I cannot find anything in the exploded parts diagrams that looks even remotely like this disc/washer/whatever. It didn't fall off of the starter that I can tell, since the starter is intact and doesn't have anything that size or shape on the end that goes to the flywheel.

Stumped here. I've tried to picture it in my mind, based on your description, but no luck. Can you post a picture of it and the rubber bits?

From the description, it has nothing to do with engine/clutch/transmission. Stray parts. Often found odd bits in various places. Once had a brand new Audi 5000 with an overheating issue when working in a dealership. Straight off the delivery truck. The cause was finally nailed down to a dead mouse (and nest) in the radiator!

One pal has a collection of tools found in various cars he'd worked on, it's not a small collection either. I'd say carry on with clutch R&R, hang the strange piece(s) on a wall in the garage as a conversation starter.

I'll see if I can get a picture of the thing (car is 60 miles from home since I have no work area at home, so can only bang away at it on weekends), and then figure out how to get it visible here. I still can't even get paragraph breaks to cooperate, so odds of getting photos to work are not good. The rubber bits flaked away into oblivion pretty much on any contact, so nothing left of them to get pictures of. The metal disc is still clean and shiny, just a bit worn on the edges so it may have been riding around in there for a while.