Pls listen to this at higher volume to hear the knock:

Click here to listen to 350z-engine

Can anyone tell me if the knocking sound is normal?

It is audible from inside the passenger cabin, but best close to the engine where the intake pipe is.
I am not sure if it is related to the fuel damper TSB, the fuel damper vibrates, but not that much.

When stepping on the gas the knock gets faster.

Thanks!

 

No one?

 

I also heard that sound from my engine too

 

It is audible from inside the passenger cabin, but best close to the engine where the intake pipe is.
I am not sure if it is related to the fuel damper TSB, the fuel damper vibrates, but not that much.

When stepping on the gas the knock gets faster.

Thanks![/quote]
+1

 

maybe a sound when u are reving might be helpful

 

When revving it is much harder to hear because other noises are louder.
Only at warmed up idle is it clearly audible.

 

I have a 05 6spd and it does that a little too. Any one know if this a problem?

 

Definitely does not sound normal man I would have it checked by the local stealership.

 

Sounds like a valvetrain noise for sure.

 

my car just 2 days ago started doing that and i just came across this to night, the valve train noise is normal in that clip but did anyone notice the very very slight knocking noise in that? mine only does it at warmed up idle also, and i ruled out detination with my scanner, so what else could it be? is it normal on highmileage z's?

 

i jacked my car up and i can clearly hear that same knocking coming from the lower part of the block. only at idle but warm or cold. does that sound like a spun rod bearing?

 

sounds like my car. I got higher mileage though.. @67k

My friend's z has 30ishK and it's absolutely quiet with minimal valvetrain chatter

 

did anyone try the fuel damper TSB? Not sure if this sound is related to that TSB...

 

no, but the fuel damper is a ticking noise from the top of the engine. this noise is a deeper knocking noise from the bottom end of the engine. i couldn't tell where it was coming from at first, it is very very very faint from the interior, and even from outside the car, so then i took a listen under neath and now its clear. its very noticeable under the car. which doesn't bother me as much just worrys me because 2k miles ago it didn't do this. unless i just couldn't hear it before because it got worse or something.

 

does a spun bearing get louder and louder as the rpm increases or quiet down or just get drowned out?

 

I don't know the answer, maybe someone else can help...

Only thing I can say for my knock, frequency increases with RPM.
And probably loudness does not change, only gets drowned out with other noises, or by AC or transmission noise.
It only is clearly audible when everything else is quiet (idle, no street noise, possibly clutch depressed and in gear, AC off, door open or near engine)

Also with higher RPM as the frequency goes up, you don't hear a clear knock-knock-pause-knock-knock anymore, but it becomes a knknknknknkn
if you know what I am trying to say (more of a constant noise).
So chances are you didn't notice it before.