Have a ' ticking ' noise coming from the engine - more noticeable when idling and doesn't seem to speed up with engine revs. Seems to come from cambelt end of engine but a lot of parts down there ! Been doing it for about 6 months now, no smoke, fluid loss or lack or performance although mpg seems to have dropped slightly. Can't tell where it originates from apart from under the bonnet . Engine is standard z20 let , reconditioned unit from Vauxhall, has 10,000 miles on it, run in properly, oil changed twice and no heavy use as yet . Brand New turbo , dy model also fitted along with fitting kit ( from Vauxhall ) 10.000 miles ago. Sorry to be so vague but anyone any ideas ? Car is a standard SRI Turbo 52 reg .Thanks.