So I had a look on the dizzy and it has the part number of 2525709AF2 and DTR04 stamped on the top. With this info, I rang up H&H too see what they could offer. I said it was a Ducellier dizzy from a 205 GTI but they didn't ask me any part numbers. They said that dizzy doesn't have any oil seals in it, so if oil was getting in the dizzy then it would be from somewhere else, which I found a bit hard to believe. They did say that there was a washer in there though, but when I asked if they had them, they hadn't, nor did they know of anywhere where I could get one from. At this point I said that if they can't get the parts then there was no point sending it to them for a refurb, to which they suggested looking for a second hand one. I think if it was on their workshop bench though they would probably be able to do something with it.
Miles is hopefully sourcing me another one so I can take one apart. A friend of mine thinks that it may be some kind of bakerlite / plastic / carbon seal and can potentially turn one up in a lathe so we can see if that would cure it.
Searching round the internet, I can't find any other car which has this dizzy part number. I am sure it must be on a Citroen (Welshpug?!!) or possibly a 405. It wouldn't surprise me if a Renault also had one. Was it only Cat cars which had a Ducellier dizzy and all the others were Bosch / Lucas etc (with a hole in the side for the vac advance)? Then when you look at the design of the rotor arm end of the shaft, you can see that it is the same internal diameter as the washer. Do Bosch dizzys have the same design? Will a washer from one of those fit a Ducellier dizzy?
Tom, you reckon the scroll on the shaft is designed to generate enough reverse flow against the oil pressure to keep the shaft lubricated and the oil from reaching the washer? Therefore if oil is flowing past, then the scroll may be blocked / shaft or housing worn? The lip seal idea sounds sensible if there is enough meat in the casting for it. If the ID is 10.05mm, what is the minimum OD size lip seal you can get? I assume that the thrust washer may still be needed to sit over the lip seal, so you would have to step what you bore out to get a shoulder for the washer to seat on.
It has turned into a curiosity question now! Internet engineering! I'm trying to keep this as original as I can though as it is on my 1FM, so I don't want to swap to putting a coil pack on there etc.