The original seal was a cork disc, with an oil slinger between it and the timing gear. It might be possible to machine the timing cover to accept a conventional lip seal, if you can find one that will fit the balancer hub. It might also be necessary to machine and/or polish the hub snout to use a lip seal on it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!