On Tue, 12 Dec 2017 04:36:26 -0000 (UTC), Arthur Wood > wrote:

>Subject: Have you ever heard THIS SOUND inside your engine?
>URL: http://www.bimmerfest.com/forums/sho....php?t=1181089
>
>Nobody on Bimmerfest knows what is causing this noise and I can't use the
>car until I figure out how to figure out what the noise is.
>
>This only started after I did some work this weekend on the valve cover but
>it sounds like someone left a socket inside the engine and it's bouncing
>around somewhere.
>
>I'm pretty sure I didn't leave anything inside where this sounds like it's
>in the intake manifold but it's hard to figure out where it's coming from
>as it's intermittent.
>
>It sounds like it's coming from the top of the engine somehow but it's hard
>to place where.
>
>You should not need a login to read that thread and download the videos.
><http://www.bimmerfest.com/forums/attachment.php?attachmentid=730369&d=1513035084>
>
>Here's just an audio file:
><http://www.bimmerfest.com/forums/attachment.php?attachmentid=730353&d=1513034666>
>
>When you download them, remove the *pdf which I added so that the MP4 would
>look like a PDF to the forum upload GUI.
>
>I can't imagine what is making that noise which is why I'm asking you for
>how to debug that noise. Thanks!

The only time I've heard a similar noise is from crank throws hitting cam lobes.
It was when I rebuilt a 352 and reinstalled the spacer used for the old timing gear.
The new cast iron timing gear had the that spacer cast into the gear.
That allowed the cam to travel in the path of the throws.
It was intermittent until the cam bearings wiped.
Otherwise, your theory is as good as mine.