In road driving (new to me car), I noticed a clanking over bumps from the lhs. On investigation it's the silencer hitting the aluminium panel above it. It's slightly loose. At the front end the clamp is slightly loose. At the rear end it all looks a bit flimsy. Like a very big P clip round the silencer and bolted to the body.
I can nip up the clamp at the front, but I don't think it'll cure the problem. I need to make the rear "clamp" more capable somehow.
Also silencers ought to have some movement.
Any thoughts on the silencer mounting and whether it banging against the aluminium is normal/acccepted?
Thanks
Graham
Clattering exhaust silencer
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Re: Clattering exhaust silencer
Banging against anything is not normal.
My most aft muffler mounting is attached to a rubber vibration isolator, screwed into the chassis. Properly done, this is all that is needed.
This example of Westfield 11 is a flat alloy floor model, with over 55000 miles.
Shown is the muffler, side view and view of the welded on exhaust pipe bracket and the vibration isolator and chassis fitting riveted into the chassis. The riveted plate has a nut welded to the back side so that the vibration isolator is easily replaced. This isolator os 15 years old, and is in fine shape.
My most aft muffler mounting is attached to a rubber vibration isolator, screwed into the chassis. Properly done, this is all that is needed.
This example of Westfield 11 is a flat alloy floor model, with over 55000 miles.
Shown is the muffler, side view and view of the welded on exhaust pipe bracket and the vibration isolator and chassis fitting riveted into the chassis. The riveted plate has a nut welded to the back side so that the vibration isolator is easily replaced. This isolator os 15 years old, and is in fine shape.
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Re: Clattering exhaust silencer
Thanks that's very interesting. The mount on mine is totally different, being a band that goes round the silencer box.
When I get a few free minutes I'll investigate further.
When I get a few free minutes I'll investigate further.
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Re: Clattering exhaust silencer
Here’s mine - standard fit. No clattering!
J
J
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Re: Clattering exhaust silencer
And I’ve seen the horrors on the underneath!

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Re: Clattering exhaust silencer
The tab on my car broke off. I replaced it with a flat plate and a nut welded to the backside. A hole was drilled to accommodate the nut, and the part riveted into the chassis. The stand off is a vibration isolator. I forgot what the length was but the thread is 1/4" or 5/16".
The bracket on the exhaust tip is a bit of a bother, but I do have a good muffler shop that has reasonable rates. I just took the muffler down to the shop and had them weld on the bracket from the old exhaust.
My car has a custom built header, built from a medium bore Mini header from Maniflow. Using the longer pipes allowed me to cut the header, turn the outlet and weld it all up without having to purchase any additional tubing, and use the original collector, keeping the LCB length at optimum length. This header doesn't have a slip fit pipe, instead having a 3 bolt flange to the exhaust pipe and muffler. I was once exposed to CO poising driving the US press demo car with a leaking slip fit to the exhaust and muffler. If you drive your W11 and find that you are exhausted after, you might check for a leaky slip fit in the exhaust system. There is not much air circulation in the cockpit, and CO can be a problem. It took a few weeks for me to recover from my experience. I now don't do any slip fits in exhaust systems. Welded, or flanged and bolted, every single time.
Of course, this header did crack at the "y", which was not modified. I don't wrap the header, but instead use a flat plate heat shield, attached with a couple of studs welded to the center branch. I have had the "y" TIG welded, and it has been good for a few years, so far.
The best bet will be to eventually have someone fabricate the same exhaust manifold in stainless steel, and put a small gusset in the "y" to hold the pipes together and perhaps prevent cracks.
And if you find that you are tired after driving your W11, check for any exhaust leaks, especially if you have rattles. Also, if you have a wrapped header, get rid of the wrapping and inspect the Y pipe for cracks. Use a heat shield rather than the wrapping. Use three bolt flanges for your exhaust, and weld any slip fits.
The bracket on the exhaust tip is a bit of a bother, but I do have a good muffler shop that has reasonable rates. I just took the muffler down to the shop and had them weld on the bracket from the old exhaust.
My car has a custom built header, built from a medium bore Mini header from Maniflow. Using the longer pipes allowed me to cut the header, turn the outlet and weld it all up without having to purchase any additional tubing, and use the original collector, keeping the LCB length at optimum length. This header doesn't have a slip fit pipe, instead having a 3 bolt flange to the exhaust pipe and muffler. I was once exposed to CO poising driving the US press demo car with a leaking slip fit to the exhaust and muffler. If you drive your W11 and find that you are exhausted after, you might check for a leaky slip fit in the exhaust system. There is not much air circulation in the cockpit, and CO can be a problem. It took a few weeks for me to recover from my experience. I now don't do any slip fits in exhaust systems. Welded, or flanged and bolted, every single time.
Of course, this header did crack at the "y", which was not modified. I don't wrap the header, but instead use a flat plate heat shield, attached with a couple of studs welded to the center branch. I have had the "y" TIG welded, and it has been good for a few years, so far.
The best bet will be to eventually have someone fabricate the same exhaust manifold in stainless steel, and put a small gusset in the "y" to hold the pipes together and perhaps prevent cracks.
And if you find that you are tired after driving your W11, check for any exhaust leaks, especially if you have rattles. Also, if you have a wrapped header, get rid of the wrapping and inspect the Y pipe for cracks. Use a heat shield rather than the wrapping. Use three bolt flanges for your exhaust, and weld any slip fits.
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Re: Clattering exhaust silencer
Thanks All for the comments. Here's an update.
I took the silencer off this weekend and did a bit of fettling of the "p-clip" bracket. I also noted that the exhaust clamp didn't manage to stop the silencer rotating around the input pipe. So after the requisite amount of polishing, I re-assembled. I greased the thread of the pipe clamp and changed its orientation so it should clamp better which it did and stopped the rotation.
So that's all fixed - the silencer doesn't move at all now. Fabulous.
However, in my endeavours, I discovered that the innards of the silencer were loose and clanked a lot when knocked. I suspect this was actually the crashing noise I was hearing! It was far too wet to go for a test drive yesterday, so we'll have to wait and see.
Looks like I have fixed a problem, but possibly not the problem I was intending to cure!
I took the silencer off this weekend and did a bit of fettling of the "p-clip" bracket. I also noted that the exhaust clamp didn't manage to stop the silencer rotating around the input pipe. So after the requisite amount of polishing, I re-assembled. I greased the thread of the pipe clamp and changed its orientation so it should clamp better which it did and stopped the rotation.
So that's all fixed - the silencer doesn't move at all now. Fabulous.
However, in my endeavours, I discovered that the innards of the silencer were loose and clanked a lot when knocked. I suspect this was actually the crashing noise I was hearing! It was far too wet to go for a test drive yesterday, so we'll have to wait and see.
Looks like I have fixed a problem, but possibly not the problem I was intending to cure!
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- Joined: Tue Nov 01, 2011 9:30 pm
Re: Clattering exhaust silencer
Fab!
I collected a speed bump exiting the car park at Combe a few years ago. A local firm removed the dent in my very expensive WSC silencer perfectly. I had drilled out the rivets. Re-packed the silencer with a whole pac of wool, and cone, which is why mine sounds rather civilised compared with Jan’s or Splat’s cars. Both of those are on 45s, mine a HIF44, but I doubt that’ll be it!
I think I might play around with it one day. Don’t have time for track days at the mo, so a legal road limit might be a decent target. i have a sound lever meter here somewhere.
I collected a speed bump exiting the car park at Combe a few years ago. A local firm removed the dent in my very expensive WSC silencer perfectly. I had drilled out the rivets. Re-packed the silencer with a whole pac of wool, and cone, which is why mine sounds rather civilised compared with Jan’s or Splat’s cars. Both of those are on 45s, mine a HIF44, but I doubt that’ll be it!
I think I might play around with it one day. Don’t have time for track days at the mo, so a legal road limit might be a decent target. i have a sound lever meter here somewhere.