BMW 318i M40 Metallic noise - HELP

[sniper_slb]

Hi,
My engine is making an out of the ordinary metal noise in addition to the hydraulic valving lifters.

This noise sounds like an intermittent "grap grap grap grap". You can watch the video in minute 0.12, 0.14, 0.17, 0.33, 0.38 and 0.44.

In normal driving, I do not hear the noise, only when I drive 3000rpm's or when I stabilize the speed at 110km / h. But the noise is not continuous.
Most of the time I only hear the noise when I drive up to 3000 / 3500rpm's, and I stumble on the clutch to shift gear or when I fully release the accelerator at this rpm.

This sound is only from the second cylinder. I already did the test. I unplugged the spark plug cable one by one. With the ignition cable of the 2nd cylinder off, it does not make any noise, at any rpm.
The engine does not waste oil, it does not smoke blue, it does not lose water.
I exprimented on a descent at 140km / h turn off the engine engaged in 4th, and does not make any metallic noise ....
I replaced the 4 spark plugs with original BMW.
I'm suspicious it's a seizure injector. I will withdraw the injector from the 2nd cylinder and change it from the 3rd cylinder and try to understand if the noise continues in the 2nd or passes to the 3rd cylinder.
What is your opinion?

Video link:

[sniper_slb]

Problem solved about 1 year.
They were worn rod covers and 1 rod with wear due ace rod covers

[magpie]

at least you fixed it