hi i have a escort rs turbo and my engine is making a horrible noise, it is like tapping , i cannot pinpoint where it is coming from . but i have relpaced cam, followers rockers and valve springs and stem seals. just wondering if anyone had come across a moise like this ..... the guy i bought it of had blown the engine up so i rebuilt the engine with new pistons engine gasket kit got the head and block skimmed ..... (if this helps any) the only thing i have not replace what i think it could be it head valves injectors water pump and oil pump. please if you have any idea of what it could be please let me know thanks