[dkim1985]

my 240 has a ticking sound during idle, thats the timing chain guides.
its just the timing chain tapping against the plastic guides.
that MIGHT cause a problem if the guides break and pieces of it inside your engine somewhere but..when that happens, the ticking stops and you'll probably end up hearing a different noise or something.

i think you may have a different problem..(dont know what though..sorry)