G'day Dattodude ,i just replaced the cam today with a standard CA18DET cam .Afetr putting all back together i made sure that timing cover was on straight and the CAS now slides in with ease and fully butts up with timing cover seems to have fixed the problem .I was thinking that the CAS was never in correct in the first place as i thing the locating half moon was twisted before it snapped .I will keep this thread open as i am still concerned of intermitent dramas .Thanks every one cheers keep the ideas coming .