Exhaust Blowing

[mikee boy]

I have removed and refitted my exhaust several times to try to cure a persistent 'blow' between the manifolds and the 90 degree bend section. Each time I ensure an airtight seal and use a large amount of Holts gun-gum and a large exhaust clamp to make sure it's all fine. I let it set fully before testing it and IT WORKS, no leaks at all. The problem comes when I ground the exhaust, either on speed bumps, bumpy roads etc, when the exhaust is pushed towards the car and this seal is broken. I have tried everything, but every time I spend a couple of hours under the car all my hard work is undone as soon as I drive at speed and ground the bloody thing. Does anybody else have this problem or is it something I'm doing wrong? How can I stop it? I can't beleive nobody elses car grounds out!!

[spivvy]

mikee boy said:

I have removed and refitted my exhaust several times to try to cure a persistent 'blow' between the manifolds and the 90 degree bend section. Each time I ensure an airtight seal and use a large amount of Holts gun-gum and a large exhaust clamp to make sure it's all fine. I let it set fully before testing it and IT WORKS, no leaks at all. The problem comes when I ground the exhaust, either on speed bumps, bumpy roads etc, when the exhaust is pushed towards the car and this seal is broken. I have tried everything, but every time I spend a couple of hours under the car all my hard work is undone as soon as I drive at speed and ground the bloody thing. Does anybody else have this problem or is it something I'm doing wrong? How can I stop it? I can't beleive nobody elses car grounds out!!

mine car grounded all the time and experienced the same problems, new clamps gum,gum nice tight seal the speed bump and off we go again i have a lower profile tyre than standard so ground a lot more so i plan routes to try and avoid them speed bumps .

So you are not alone

[mikee boy]

As it seems to be a standard problem, I think I'll try to fit a flexible link between the manifolds and the stainless steel exhaust, i.e. replacing the 'hockey sticks'. I know that some front engined cars have a flexible steel pipe in after the manifold to cope with the engine twisting on its mountings (mk 1 and 2 golfs especially). I'll keep you informed of the outcome.

[Rozza!!!]

On my S2 (don't know about others) it is the 90 degree bends that hit the road when the car grounds out. Won't replacing them with flexible ones mean that when the car grounds, the flexible pipes will simply be torn apart? Not to mention that the leading edge of the pipes under the car may also the dig into the road and cause untold damage? Also, on my S at least, as the manifolds are not on at the moment, there is nothing holding the pipes rigid at the front of the car, so this may also cause a problem.

Roy.

[M@H]

My interpretation would be to put the flexible pipe stuff over the top of the join between the manifolds and the 90 degree sections, add loads of gum inside etc.. then clamp it all together.. !?

The flexi stuff would indeed get severely ruined if expesed at the bottom leading corner.. one of my old solid ones was hammered into a D section by the road (fitted SS ones instead)


Cheers
Matt.


>> Edited by M@H on Monday 5th January 11:27

[RichardR]

Halfords do a silver self adhesive exhaust tape/bandage which I've found quite effective as it seems to have more give in it. The exhaust pastes and gums seem to harden (as designed) and then crumble/shatter when subjected to knocks and bumps. I guess this isn't ordinarily a problem for most cars, but is obviously an issue for the S.

I take the clamp off, put the tape over the join with a reasonable overlap in both directions, and then replace the clamp over the top, and I've done this at both ends of the downpipes, with good results.

I just need to sort out the manifold/gasket now.

[thegamekeeper]

try using RTV Silicon available from B&Q and other good retail outlets, very effective sTeVeR

[z_chromozone]

Has anyone tried to fabricate a sheild for the exhaust. It may not be too comfy if you ground out on something solid, but it has to be better than buying a new exhaust all the time.

My V8S only seems to ground on the backbox, I suppose the exhaust is routed in a different way.

Z