Knock? FIXED
 

I know our engines sound like tractors, so i've tried not to let little things get under my skin. But the other day i am sitting in the driveway with my car running and my dad stops, stares at my car and asks if my engine is knocking, so now i am paranoid. What do you guys think?

[ame="https://www.youtube.com/watch?v=YCc7Xoo4Dzc"]Knock? - YouTube[/ame]

Alright boys and girls, its time for an update. The part finally came in and i had it installed by Parkway Subaru in Wilmington NC. They actually put it in for free for me because when i originally had the car being looked at i was just outside of warranty range, so i just want to give a big shoutout to them as they have always looked out for me.
So the actual part that they replaced was the Secondary air pump, creates a vacuum at idle and all that jazz.
Did it actually work? Well yes, the noise has completely gone away and now i can breathe again knowing its not a valve train issue or anything like that.

Is it an automatic?

edit: nvm. I see. I think it's that cam-driven pump on the right side.

Sounds stock (normal)

Dude, that is NOT normal.

Definitely not normal. Rev it and see if the sound follows the rpm.

Get someone to stand out side to record the video while you rev it.


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That vacuum pump is at the back right corner of the engine.

Sorry, but i just got used to mechanical fuel pump on carburator engine. Also my car is flashed with oft and valvetrain are now loud

I'll try and get an updated video tomorrow morning

Someone else here made an excellent recording of the failed vacuum pump then, I think, replaced the pump himself.

Most of those sounds are normal... but I hear a knocking sound at a random pace. That right there is not normal.

https://youtu.be/LPLIiiiOcas

Doesn't seem to carry with revving.

I had that same noise...

https://www.dropbox.com/s/2ppc5iw92r...83517.mp4?dl=0

It was a deformed rocker arm.

Here's my thread.

http://www.ft86club.com/forums/showthread.php?t=81496

That also fits with the vacuum pump failure.

Following that first case, my running theory (conclusion?) is that something in the pump causes it to lose clocking. Parts collide when there is no load on the pump and they bounce around.

It seems to run normally under load/higher speed.

edit: Nah. I'm full of shit. Thank god @N1rve posted. Here's the thread/sound I was thinking of.