WOT rattling

[James]

I don't expect a specific answer for this, but its worth a try I guess.

Under WOT I hear a type of... Rattle noise... From the driver side of the engine bay. It sounds almost as if you had a big bag of marbles and were bouncing the bag around. It's only under full throttle that I hear it. Sounds like maybe from the head? Hard to tell from the drivers seat. I've investigated it, couldn't find any loose bolts or fittings or anything.

Now I do think I have a pulley getting ready to go out but I don't think the two noises are related. Under normal cruising condition with maybe 25% throttle I get a wobble sound. Goes away with more or less throttle.

 

[MellowVR4]

maybe a harmonic balancer?

 

[James]

The rattle, wobble, or both?

That was my guess for the wobble. Or water pump. But I can't see how the pullies can make that chatter.

The car idles fine, drives fine, pulls strong. Nothing in the oil, coolant is clean.

 

[MellowVR4]

when did this issue become noticable

 

[James]

I would say... After a cracked the valve cover? Two hairline cracks. I assume the notice was just sounds coming from the head and was more noticeable due to the cracks letting sound through.

I have a new valve cover and gasket now.

 

[James]

But also, prior to that I was unable to to a real pull in the car due to phantom knock and boost creep. Along with loud lifters. I fixed all of this at the same time. So the problem could have been from before but went unnoticed.

The wobble has been there since I got the car.

 

[turbowop]

Hopefully it's not really bad audible detonation.

 

[MellowVR4]

^ whats that?

 

[James]

Logger shows no knock. And like I said, it pulls hard at 18psi.

 

[MellowVR4]

Axle support bearing?

 

[James]

I'll check that out on my next day off! I didn't think suspension. The sound "sounds" like its coming from higher up than that but who knows with how sound travels

 

[5OF2k]

Does the car still have the balance shafts??

 

[James]

Good question I've never checked. They removed all the emissions, egr, ect stuff that everyone removed so I would assume the PO did a balance shaft elimination on his rebuild. But ill double check to be sure.

I assume you are suggesting that for the wobble noise and not the chatter.