Hey Guest!
Do you have a rebuildable core?
Can something like this be used? (It is a Mini item)
https://www.7ent.com/products/kad-fluid-crank-damper-kad1019191.html
I purchased one, in stainless I think, from Australia. Don't recall the supplier. Works great, but the timing marks are set up for a mini, so I still need to re-mark the pulley or fabricate a new pointer. Let me know how it goes; and I can dig for supplier info if/as appropriate. Good luck!
Phil