Vigor distributo keeps going bad

This is for 92 Vigor that has a third distributor in a year. I replaced distributor last February because it was leaking, oil was burning on exhaust and causing a stink inside the car. Second distributor caused the same thing in October, now it does the same thing in February and I an tired of exchanging distributors. Granted there is 240k on that egine but what does it have to do with distributors going bad?

Thanks for all your help!
:banghead: