Ford CVH engine, OIl coming out of air box?

I have a Ford Orion with a cvh engine, There is oil getting in the air box, I have replaced the breather pipes as i know this can cause the problem, But there is still alot of oil getting in and covering the air filter. I have some knowledge of the cvh so i can do most basic things to it, Would an oil change help as it was owned by an elderly gent before us and im not sure how well it was looked after. Thanks