VZ V6 Rattle!

[f1tzy]

*cough*weld*cough*

 

[mattvz]

I take some pictures of how I fixed mine when I get a chance . mine is still quiet.

 

[Breno]

hey is anyone experiencing this with a full sports exhaust change ie extractors new cats, cat back or just changing the cat back?

i just got a full exhaust done and although i dont get it at idle it happens like many others at 3000rpm. frustrating after spending all that cash.:bang:

after having a read on other threads i came across this one (https://forums.justcommodores.com.au/threads/alloytec-exhaust-fun.56190) talking about different exhaust combinations on the alloytec.

It goes on explaining along the lines of one of the set ups, when it goes from dual from the cats into the first single muffler, that the two banks fight at that rpm who has right of way first and resonates inside the muffler and causes vibration, which causes the crap sound.

then explains how he got rid of it by changing the exhaust set up.

who knows if its the truth but its kinda interesting and makes a little sense.

just another thing to think about i guess. lol

 

[Torquative]

alright well ive managed to find where its coming from when i had the car up on jacks on the weekend.

My next plan is to kevlar wrap the exhaust then re-bolt the heat shield back on because its the heatshield thats vibrating BUT it seems to act like a bash plate as mine has been scraped and dinged to the buggery which wouldnt be helping and possibly causing the vibration if its rubbing on the exhaust pipe.

I figure some wrap around the pipe will act as an insulator between the metal pipe and metal "heat shield"

 

[mattvz]

Hey Torquative,
I just put some exhaust wrap on mine and rebolted and re-clamped it and no noise .
But I was thinking about your problem and was wondering , before you put the hose clamps on the heatshield did you bend or remove the flat tab bits where the heatshield halves are ( where the joins are ) I removed mine so that when the hose clamp went on it would not foul on these and was going onto a round surface , otherwise it will not clamp the two halves together , I did this on the end of the heatshield just enough to get the clamp on.
Cheers ,
Matt

 

[Torquative]

nah I didnt I was in the middle of throwing a hammer at the snapped wheel studs in 42 degree temps so I was just after a quick fix.

It'll come off this weekend hopefully to check thats the problem and I'll exhaust wrap it shortly when I have the money

 

[Poves_89]

vibratin heat shield

Could it be that the muffler is vibrating against the heat shield thats it sits near coz its the same with my VZ ute had a twin 2.5" system from cats and i hear a vibrating noise like a buzzing to me it sounds like the vibration from heat shield


I JUST WENT AND GOT MY EXHAUST SYSTEM CHECKED OUT AND THE HEAT SHIELD THATS AROUND THE PIPES THE BRACKET INSIDE HAD SNAPPED COZ IT BOTTOMED OUT ITS NOW FIXED

 

[mattvz]

Still havnt taken any pics yet of my fix.
I was thinking , another way of finding the rattle is to remove the heatshield for a moment when cold . start - test- short drive and see if the rattle is still there .
Matt

 

[Torquative]

alright all I had the car up on jack stands again on the weekend so I crawled under and removed the heat shields in question.
6x 10mm bolts and a bit of jiggling they came free.

One side lost alot of white foamy type insulation that had broken away. As had the other side BUT it also has lotsa rocks in the shield.

Magically the rattle has gone! Theres still a slight vibration/rattle which sounds like its coming from another shield BUT its barely hearable.

So the plan from here is to remove all the factory insulation, as most of it has broken away to allow metal on metal anyway, kevlar wrap the exhaust pipe, then chuck the shield back on.

It seems to be more of a bash plate then a heat shield, mines copped a beating. Currently I only drive the car 2 streets to get to the freeway and 2 streets to get off the freeway at either end, so the chance of hitting the pipe is minimal but the sooner the plates back on the better.

 

[Summer-Sickness]

alright all I had the car up on jack stands again on the weekend so I crawled under and removed the heat shields in question.
6x 10mm bolts and a bit of jiggling they came free.

One side lost alot of white foamy type insulation that had broken away. As had the other side BUT it also has lotsa rocks in the shield.

Magically the rattle has gone! Theres still a slight vibration/rattle which sounds like its coming from another shield BUT its barely hearable.

So the plan from here is to remove all the factory insulation, as most of it has broken away to allow metal on metal anyway, kevlar wrap the exhaust pipe, then chuck the shield back on.

It seems to be more of a bash plate then a heat shield, mines copped a beating. Currently I only drive the car 2 streets to get to the freeway and 2 streets to get off the freeway at either end, so the chance of hitting the pipe is minimal but the sooner the plates back on the better.

good stuff mate. i had mine in for a service on thursday and he had a look for me, he said it was fouling (as we all expected) and he bent it away, bam rattle gone! it has ever so slighly come back, i cant hear it in the car at all, but when i have the a/c on (making the idol revs higher) i can hear it slighly whilst outside the car. im happy with it for the moment, but when i get extractors n high flow cats put in i will be using ur kevlar wrap idea lol. but good to hear the problem has been pin pointed.