I know blue smoke means burning oil, but where from? The engine is rebuilt, could it be the turbo? or.... a long shot....... I have a small gearbox oil leak and is dripping onto the flexi on the exhaust, could it be possible it's soaking thru the flexi causing the smoke?

 

Is there any play in the turbo shaft up and down? should be a small amount.Might be worth whipping off the turbo hose and having a check

 

Checked the turbo and all is ok. I'm prity sure it's being caused by 'box oil seeping thru the flexi now tho as I've been underneath and the flexi is covered in oil and is smokin!

 

valve stem seals

 

There new, the head was rebuilt no more than 400 miles ago

 

Cant see it being the oil leak if it's a "small oil leak". It would have to be leaking shit loads for it to soak through the flexi and cause it to smoke out your exhaust. What stem seals did you use??

 

mate there is no way there is going to be anything getting in the flexi hose, it has a very soft metal insert inside it and the braiding gives it strength and obviously the ability to flex.... well thats what i have found on every other exhaust system i have seen, Think about the amount of water that would seap through and then boil in your exhaust pipe when driving downt the road, or how much gasses would escape when you drive down the road.
Blue smoke is usually valve stem seals mate and i know its hard to believe as you have just rebuilt 400 miles ago, sometimes they dont seat right, other brands are shit etc etc.
My advice is to change em anyways if the smoke carrys on going, otherwise youll go round the houses trying to find a fault out because you assumed rather than checked. Im in the middle of fault diagnosis on a fuel issue and i leave no stone unturned as once its done it is done and you can tick it off the list knowing that it wont come back to haunt you. Although things seem pointless and a job lengthener in the short run they dont in the long haul. Hope this helps matey and that blue smoke stops!