Knocking sound...help me diagnose

Sorry for the poor video quality...I didn't want to leave it running too long.
Went to start my 2006 GT the other day and there's a distinct knock. I keep it maintained and don't beat on it. Took off the driver side cam cover and don't see anything obviously wrong. Can't tell if the noise is coming from the driver side or the middle, but it's at the front of the motor.
Car has stock short block, KB 2.6L, Comp 127500 cams, valvesprings, retainers, and phaser limiters. Makes 11 psi but I rarely push it too hard. Tuned by Lito. 60,000 miles on the car.
I'm thinking it's a phaser or chain tensioner, but no idea how to tell.
Can anyone give me some direction?

Update: I removed the belt and tensioner because the tensioner is the last thing I touched (steeda, took it apart a couple months ago to narrow down a squeak from the FEAD which turned out to be the alternator). To rule out the FEAD I started the car with no belt and let it idle for about 15 seconds. No knocking during that time.
So, it's either the tensioner, the Innovators West damper, the KB, or something else belt-driven.
FEAD consists of FRPP a/c delete, IW damper, KB, aftermarket idlers, stock power steering, stock water pump, and aftermarket alternator.
Thoughts on what could make that sound?

With the belt removed have you free spun all the pulleys? If the is no knock with out the belt it's not engine for sure (thank god)

How is about the supercharger bypass valve?




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o2sys said:

With the belt removed have you free spun all the pulleys? If the is no knock with out the belt it's not engine for sure (thank god)

How is about the supercharger bypass valve?




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Yes, free spun all pulleys and manhandled them a bit. The only pulley with end play is the power steering but it's not the culprit. Alternator was squeaking badly a couple months back, but I oiled the bearing and until today it's been fine.
However, I have noticed some belt slip when clutching between gears, which is why I inspected the Steeda tensioner today.
Update: car is buttoned back up with no knocking sound which is great, but what was it and why is it gone?? Also, alternator is squeaking again. IIRC it's a PA 160 amp which has been fine.

Can't comment on the knocking but do you know if your alternator pulley is clutched? You mention an aftermarket alternator and if it didn't come with a clutched pulley, you'll get the symptoms you're describing.

Can you try a different belt?

46addict said:

Can't comment on the knocking but do you know if your alternator pulley is clutched? You mention an aftermarket alternator and if it didn't come with a clutched pulley, you'll get the symptoms you're describing.

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No, just an 8 rib chrome pulley. Do you think the lack of a clutch caused damage to the alternator bearings?

Marble said:

Can you try a different belt?

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I could but I haven't. Currently using an 8 rib Green belt with maybe 1000 miles on it.

If you glazed it you might consider it. At least you would have a back up.

Marble said:

If you glazed it you might consider it. At least you would have a back up.

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Belt looks good, and I have a spare in the trunk. My alternator is squeaking pretty bad and I have a hunch the tensioner may be at fault. The belt length keeps the tensioner in the middle of it's operating range, but I wonder about the black Allen head set screw in the tensioner. It almost seems like it's there only to keep it together when installing the tensioner, and then only reinstalled if removing the belt(?). I've had the set screw in it the whole time (a few years), and maybe it's fine. Can anyone with a Steeda billet tensioner chime in?

Here's a pic of the set screw in the tensioner. Not sure if this should be removed while installed on the car, or left alone. It doesn't seem related to the knocking sound, but since we're talking about the tensioner as a possible culprit to the alternator issue, here it is.

BlueDevil said:

No, just an 8 rib chrome pulley. Do you think the lack of a clutch caused damage to the alternator bearings?

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I'm not sure on the alternator bearings but I know the lack of a clutch can put stress on the belt. As you upshift, the crank pulley is slowing down while the alternator is trying to maintain speed, so without a clutched alternator pulley the inertia is transferred to the belt in the form of belt slip. At least that's the way I understand it.

Does anyone know where I can get an 8 rib clutch pulley for my alternator?

Zombie thread, activate! So, I'm diving back into this after not much time working on it. After much research I was convinced it was the chain tensioner. Took timing cover off to find no obvious damage or wear. I'm at a loss here. Here are new videos...one without the belt and one with the belt. I went back to the standard belt (removed Gates Green belt) and squeaking is gone. It sounds like it could be inside the motor (rod?), Or on the front (phaser?), BUT it isn't there with the belt off . Supercharger? Balancer? I'm really frustrated with this thing.