I have just bought my wife a ford focus 1.0 st line x on a 69 plate (125). sounds horrible when accelerating away from traffic lights, sounds like something wrong with manifold as it seems the noise coming from there.... i traded in a 2018 focus 1.0 eccoboost st-line (140) that was very quiet, not like the new car.

Have ford change the engine in the 69 plate models, as i drove on on holiday and it didnt sound like this. I have it going back to the garage this week, so they can look at it, but see on the forum that some people have been fobbed off, by ford saying nothing wrong... surly it should not sound like a lawn mower when you getting off the line.

Any help would be appreciated.       

Yes, the later model is a totally different design.  Uses a cam chain instead of a belt amongst other things.

Having had both, I think they do sound awful, but other people seem to get used to the noise quickly.

Mines not the 1L but it’s a quiet thrum to this day. Almost 50k miles. 

Strange, I have the 1.5L but it's still 3-pot and it purrs like a cat lol. Sure it's a little more raucous when it's cold, but that's not abnormal.

Does the sound get better once the engine has reached operating temp?

Is the symptom more noticeable under strain of acceleration or can you also produce the noise in neutral and just revving up?