Loud vibrating buzzing noise after changing cat to manifold gasket

[Alias]

Hi,

I changed the cat to manifold gasket today as the old one was completely rotten and blowing. Got the gasket fitted and all tightened up but now the car vibrates like hell when accelerating. It only does it under load and is slightly better in 5th but still there if you put your foot down. I double checked all the bolts on the exhaust and they're all good. I checked the top engine mount, its a bit worn but wedged it to test and it did nothing to improve the noise. I can see anywhere that the down pipe or cat could be touching anything they shouldn't so am a bit stumped.

I ran out of light this evening but will check the engine mount under the battery tomorrow to be sure but not really sure how this would have changed after fitting the gasket.

I got the gasket from Ktec and followed the guide on here so shouldn't be down to a cheapy part (or my workmanship, hopefully).

Any ideas or suggestion would be much appreciated as its hugely annoying and really want to get it fixed.

Cheers,

 

[Saul]

Hi, Its most likely touching the ARB.

 

[DomP182]

Just throwing it out there but I once refitted my valver cat upside down and it caused the manifold to touch the bulkhead under load, horrific noise. I bet yours is doing similar

 

[DomP182]

A bit like if your brake fluid reservoir touches the back of your engine block.

 

[Alias]

Im pretty sure I didn't put the cat back in upside down but I'll double check when I'm back with the car later, don't think it would have gone back over the sub-frame if I had though.

Its definetely rubbing against something, I'll try to have another good look underneath but did look like it was clear of the sub frame and ARB but I may well be mistaken.

Not really sure what else to check after though, there can't be that many things down there it ciould touch.

 

[Simon_16v]

If you had put the cat back in the wrong way round you wouldn't have been able to plug the lambda sensor back in.

On a 182 anyway.....

 

[Alias]

I didn't think I could have and it would have been a pretty obvious **** up but just seems a bit odd that its only happening now and was fine before changing the gasket. The only difference now is the gap between the cat and the manifold is slightly bigger as there is actually some gasket material between them.

 

[koi]

Checked the heatshields?