i have experience with 781/791 OHV engines - it's the same design like 1.4 OHV 44/50kW in fabia. it use still same timing chain set, but fabia set valve clearance (lash) by hydraulics tappeds, not by screws manualy. i have heard your recording, it's really seems like chain noise, but i'm not sure. if you measure the chain's pitch after for example 10000km, is it ok? if yes, i think the noise is produces by something other, if not, the cause find in all timing system.

Thanks rosta,
How do you make the measurement you have suggested. What do you mean by pitch?
It's not very easy to access the chain unfortunately because the cover is bolted in the block and in the oil vane.

Please explain.

After I have changed the chain the noise you have listened to in the recording was gone completely so it's the chain.
I will have to post a new recording now, after the 8000km. I listened to the tappets and even checked them, they are more than ok.
It seems to mee the rattling goes when the idle is not stable.

I start to believe that the designer of theese engines was ok with the chain-noise. They mounted a double chain to make it hard to fail, even if it gets a little louder. Almost all the other engines from VW, BMW, Honda and so on they have thinner chains but with tensioners. This (skoda) is the first engine with chain I've seen with no tensioner.

The only ugly part I see in this is the noise. Besides that the engine is very nice. It's quiet (taking apart the chain noise), it produces reasonable torque for it's size at low RPM and the consumption is ok. Fairly strong engine, although it's pretty old.