MGTF causes smoke curtain

I have a serious issue : when my TF has not been used for a couple of weeks, right after startup of the engine there is a huge amount of smoke coming from the engine bay. It is coming from the exhaust manifold, in particular the flexible piece under the car, and the big flange above that where all pipes join together.
There is no oil leakage on the floor, also I cannot see oil dripping on the exhaust pipes.
At cold start the car has blue exhaust gases, this disappears when the engine is warm, but when the engine is warm there is still coming smoke from the engine bay.
See the movie : smoke
I suspect that the valve stem seals are leaking badly, causing oil to come in the exhaust pipes, that is leaking through the exhaust gaskets and causing smoke.
Has anyone had a similar issue ? Or other suggestions ?
Thanks, best regards, Theo

How does it smell? Looks like exhaust fumes from first view...
Maybe new gaskets would help, and correctly tightened bolts.
Regards
Christof

It is definitely not exhaust fumes. When I turn off the engine, the smoke remain for about 10 minutes, so something is burning on the hot exhaust. Can be oil or water. It smells like burned rubber, so the cam and timing belts were my first suspects, but these are ok. If there would be an external oil leak, dripping on the exhaust, I should see oil on the floor, there isn't. The fumes are the worst just after startup, and then become less, so the theory is that oil has gathered in the exhaust pipe when parked, and is burning after startup. In that case the only probable cause are the valve stem seals, by deduction. Now I want to check my theory with experiences from other F or TF owners, I am sure my car is not unique in developping typical breakdowns.

If that was oil inside the exhaust pipes burning, as you suggest, then you would see it bellowing out of the exhaust tips!

If the CAT was blocked, preventing this, then you would hear the exhaust blowing.

What happens if you remove the oil filler cap, any gas there.

Seen something similar when a freind over filled the engine with oil, and the breather pipes were blocked!

Are you loosing oil or water?

Oil leak from head gasket, or cam seals?

Compression test???

Any plastics or rubber touching the manifold?

You are going to have to take a very good look to identify the source!

Hi, I checked the oil filler cap, there is air blowing from the oil filler opening "blow by" but no fumes coming from the filler opening, When I put my hand right above the filler opening, the one on the camshaft cover so not the one in the boot, the amount of air can be compared with slightly blowing on your hand.
The garage thinks it is the camshaft cover gasket, based on the movie. That would indeed be possible, the only thing is, there is also a large amount of smoke coming from under the car, the flexible piece, that I cannot explain from leaking of the camshaft cover gasket. The is no oil leak under the car on the floor. No coolant leakage, the coolant also remains at the appropriate level, there is some oil usage.
When I drive the car daily there is some smoke, but only can be seen with the engine cover removed. When the car is parked for a few weeks, then the first 15 minutes there is a real smoke curtain, until the oil has burned. So apparently it piles up somewhere on the exhaust during long stand-still. If my theory is correct, it piles up in the exhaust, leaking from the cilinder head, along the valve seals, into the exhaust. Also after a long stand still I can hear the hydraulic tappers, for a few minutes, indicating that these are without oil, in my theory that has leaked into the exhaust, and needs some time to be filled with oil again.
Taking a good look at the exhaust tips is a good suggestion, right after cold start, indeed I would expect oil to be there. That would also mean that the cat may have problems.
But I was curious if this kind of smoke curtain has happened to other MG owners, and of course what was the solution.