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.