A very nice salesman sent me (for a small consideration) some proper felt washers for use as a secondary seal. I've not used these before, but I believe that they should be soaked in oil first.

Making them oily is A Good Thing as far as I'm concerned - but should I use thick or thin oil, plaster them in grease, or what?

i wouldn't say grease, i don't think it would soak into the felt very well. thin oil, or engine oil probably best

I've got some 600W oil at home - that would be good!

This one I can answer! They are used a lot on old triumphs (which I'm rebuilding at the moment) and the consensus is to soak them in (clean!) engine oil for a day or so before use. If its a single use item (ie you won't have to undo it very often, and if you do it will be replaced - eg inside an engine), the other option is to soak in wellseal or some other similar product - it what we do with the felt seals around the crankshaft in a TR4....

Chris

It will be sealing the gap between a fixed part and a rotating one, so the wellseal might not be a good idea!

Engine oil sounds like the thing to use...

Many thanks,
David

....still wondering David