hi all,my vacuum advance on my datsun sunny 1200 does not work where can i get one new or second hand if so how much thankyou

Get it at the wreckers. Any Datsun or Honda with Hitachi D4A/D4F/D4K-type distributor will have a vacuum advance can that should work. Check your Sunny distributor for type, it is stamped on the side of the distributor.

When buying new, the price varies by the exact car -- from $12 to over $100 for a new unit. But they work fairly the same, they only have an effect at part throttle. And your A12 engine will run OK w/o vacuum advance if you plug the hose.

I've used these guys in the past: http://www.advancediaphragmoptions.com/

for hard to get aussie mopar related stuff. If they don't carry a new one to suit, they can re-build yours and send it back.