shld there b a one way valve fitted to my breather system on my saff? its stage 3 so has the catch tank up next to the battery.reason im asking is because it still smokes on over-run! its had a full re-build and still doing it.iv dun all the usual things people have sayd it was, valve guides,stem seals, i think it has got better since i started using the mobil 1 15 50,not sure tho.been told there shld be a one way valve fitted to breathers but also been told otherwise! my brothers 3door has one fitted but doesnt have the breather system on it (catch tank).. im confused