190 celica timing chain cover

[Alboy]

I am looking to change my timing chain

as it rattles on start up.But their is a metal pipe going across the front of the head face stopping the cover frpm coming off .It goes round the back of the engine and disappears into the head with no visible way to get it out.does anyone know what it does and how to rem0ve it.it seems to be emmissions related .i can find no mention of it in the workshop manual.advice needed please!!!