Are you still there?
Try using flushing oil to clean out the rubbish first . Then just use the good quality specified oil. I had an escort for 15 years - a 1.3 petrol and it ran well. i serviced it all thise years too. I used Partco oil 20/40 but chnage it and the filter every six months in short runs.
Is the mixture correct? Is it smoking? I presume you change the air filter regulalrly.