I need to join 2 pieces of breather pipe together. I tried looking for a\nplastic hose joiner at my local motor shoppe, and found some plastic ones\nwith ribs on (just what I wanted). The only sizes they sell tho are 13mm &\n8mm. My pipe is approx 11mm. I feel the 8mm will be too loose, and I've\ntried the 13mm and cant ram it into the hose at all, too big.\n\nI've got some copper piping which is just the right size. I plan to cut a\nlength and fasten it with 2 jubilee clips. Only thing I want to know is, is\nthere any chance the copper may 'deteriorate' and damage my engine? The\npipe is breathing into the plenum chamber (it really is a breather and not a\nvacuum line). Is there any chance the copper piping could emit anything\nthat would damage the cat etc.........?