Engine abnormal noise

[cooper66]

I have a 65 4.2 E type, complete engine overhauling, crankshaft +10, new pistons (Mahle), new valves, timing chains etc. The engine has now 3000km, of course regular oil changes with the filter, the engine runs perfectly and smoothly, torque and power is there, temperature stable arround 70°c. We checked the upper timing chain tension this is good.

My problem after 1500km I started to have a kind of rattling noise. This noise appears only between 2000/2500 rpm, very difficult to have this noise without running the car on the road. This noise is not regular, appears at cold and hot engine, it looks like a conrod bearing failure but it's not.

Initially I suspected something not fixed or vibrating in the engine compartiment but no this is coming from the engine. I took several videos in order you can advice any rootcause :

First video :
https://youtube.com/shorts/jvRxZA4jPkU?feature=share

here we can here very well :
https://youtube.com/shorts/Y7QrM5IGyI0?feature=share

We can detect it at 11s :
https://youtube.com/shorts/izdSYpIWX9w?feature=share

I'm lost need your help / ideas Gentlemen.

Thanks in advance

[Jack the lad]

Hi Pierre, my first thoughts are to let it develop for a while, it may then become obvious where the noise is coming from. If this worries you then I would take a few tools with you and when ready to drive it down your test road, slip off the drive belt to the water pump/alternator and repeat the test quickly and see if the noise has gone. If it makes the noise in the garage, get a mechanics stethoscope and have a good listen at the power unit including clutch and gearbox. This will be a few Euros well spent as this took will also work on your modern bikes and cars. Good luck with it and please let us know what you find , cheers John.

[malcolm]

I always find it incredibly difficult to place exactly where a noise is coming from - it might sound like a particular place but be transmitted from another.
i also find I have a tendency to worry too much about noises when everything is running fine! That's probably just me?

[christopher storey]

I heard it best on the first clip and could hardly detect it on the others. The interesting thing is that it appeared, in apparently identical form as to pitch and rhythm etc. , on both acceleration and on the overrun. It did not sound mechanical to me, but sounded more like a resonance effect which one might get from a loose sliencer baffle or something like that . Have you got any exhaust shields installed , and are they all secure ?

[Fuel.inj]

I’d also go for the heat shield rattle diagnosis first.

[rswaffie]

Also check that all the exhaust manifold nuts are done up tight to the down pipes. Some of mine were not tight and the metal gasket was rattling, plus a bit of a metallic clonking when going over bumps. It sounded similar to yours. I tightened them all up and noise went away.