2005 v35 skyline rattle noise between 2000rpm-3000

[Blakeo]

Hi guys, my girlfriend has a v35 skyline with the vq35de engine. Around 2000-3000rpm it has a rattle noise in the motor but it won't do it all the time. I don't believe its heat shields but I've pried them off and made sure they have more than enough clearance not to touch exhaust. 

I've read on here that the issue can sometimes not be the chain but the vtc cam gear can cause the noise. Is there anyway I can diagnose this to be 100% sure what the issue is as doing the chains is a big job especially if it's not the problem. Car has no rattle on start up and otherwise drives nicely and has no power loss. 

[Blakeo]

Anyone? 

[Leroy Peterson]

Is the rattle definitely from the engine? Does it happen when in neutral, parked, with someone standing in front of the motor with the bonnet open?

[V35_Paul]

My mates 350z rattles sometimes because of the ac.

Bad pulley or ac clutch

[Blakeo]

Bit of an update. I did the whole timing except for the two secondary tensioners which are good anyway. 

Also replaced the right side bank vtc gear. 

Doesn't appear to be making noise anymore, must have been chain, tensioner or vtc gear. 

Will update post in couple weeks when can be sure it is the solution. 

[Blakeo]

Okay after a couple weeks, it has made the noise a couple times which leads me to believe it wasn't the timing chains, vtc gear or tensioners which is unfortunate. I have modified the cat heat shields to ensure they cannot rattle. 

I have replaced fuel dampener and AC compressor belt has been taken off and isolated. I have replaced both bank vtc gears and also have replaced the vtc solenoids on top of the gears. Which has cost $1200 just in parts from nissan not to mention gaskets and so furth. 

Does anyone have any suggestions? I have it booked in on Wednesday to a mechanic who specializes in 350/370z's only thing I'm concerned about is it only happens rarely now maybe once a week. 

[V35_Paul]

Having it only make the noise maybe once a week is going to be hard for the mechanic to diagnose.

Maybe you can get a recording of it when it happens. 

[Robinhood]

I have a rattle i put mine down to engine pinging detonation so has a auto mechanic only low revs