Strange bearing/resonance noise

[AVPWorks]

Hi all! My name is Albert from Barcelona, and I'm new here... I'm looking for some help cause I'm going crazy.

I own a Renault Clio R27, and I broke my OEM engine last year, so I put in a "new" one, about 40k miles engine, the engine is f4r 836 (from the resty clio mk3). Since then, there is an strange noise at 3,5k to 4,5k rpm range, and it sounds like a bearing or scouring noise.
And when I lift the gas, it sounds like if I put the rear gear. When I push the clutch, at any moment, the sound disappears.
It really sounds from the engine, but don't know what could it be.
I recently changed the exhaust manifold, to a decat one (OEM one, but with an Y instead of the first Cat), and the noise has made louder. Could be anything from the head? Seems to hear it more on the timming belt side.
The solenoid is from the old engine, so it is a 197 solenoid into a 200 (203 in spain) engine. Don't know if that could make that sound.

We have done the timming belt (full kit), and water pump. We removed the aux belt and still doing that sounds. Tried to put softer engine mounts. Switched from handmade without cat to oem exhaust with second cat, and the noise stills there...

To help to imagine the spund, it is almost like if the timming belt is too tight.

Any help will be grateful.

Thanks

Greetings

PD: sorry for my english.

 

[Gus]

When you are driving at 3.5-4.5krpm if you press the clutch in the sound stops ?

If so it's likely to be gearbox related or clutch related. Do you have any issues or crunching when changing gears even at high rpm.

But you say it started when the engine was replaced and has been like that since the new engine went in.

Maybe someone else has had experience with this.
@bloke

 

[AVPWorks]

When you are driving at 3.5-4.5krpm if you press the clutch in the sound stops ?

If so it's likely to be gearbox related or clutch related. Do you have any issues or crunching when changing gears even at high rpm.

But you say it started when the engine was replaced and has been like that since the new engine went in.

Maybe someone else has had experience with this.
@bloke

Yes, when I press the clutch, then the sound stops.

Sorry I forgot to mention, when we put the engine, we changed the 3rd and 4th gear sincros, so we disassembled the gearbox... Could be something wrong in there?
The car has 257k km

 

[Gus]

I could be wrong but sounds like it could be the clutch release bearing. Google that to see if the noises are like that .

 

[AVPWorks]

In my case, it only sounds on road, when the car pulls its weight. And it is like a knocking sound, it is continuous, the louder pint is at 3,8k-4k rpm.

 

[bloke]

did you change the slave when you had the box off?