Ratteling Muffler

[rmel]

My muffler developed a very annoying rattle about a 1 1/2 year ago which drove me absolutely nuts

Decided to just replace it with a SAV 2'nd party muffler (steel zinc platted). Thought the noisy original
would be a decent backup spare -- it's Stainless steel and served me for over 12 years.

Well after a very long drive to Mojave recently the replacement muffler decided to compete with the
old one as the new rattle champion -- CRAP!

So I decide to remove the new muffler and perform exploratory surgery in the hope to find something
that broke free that could be welded back together. And yup, I found something that I think may apply
to all the Pinz'y mufflers.

Opened.jpeg (319.7 KiB) Viewed 3079 times

Cutaway section shows how the muffler is constructed. There are three chambers, and two resonator pipes
held in place by a pair of circular plates. What was evident is that although the pipes are welded to the two
plates, the plates are NOT welded to the outside body of the muffler. They are held in place friction only.
The outside skin is wrapped around the guts then one seam is welded and end caps welded in place. So that
was the problem!! The insides eventually worked free from friction to the outside skin and vibrated. I believe
what happens is that over time carbon builds up, works it way to that disk/skin then acts as a lubricant then
the plates start vibrate and get worse over time.

Stiches.jpeg (330.26 KiB) Viewed 3079 times

What I decided to do was to add several "Plug" welds around the outside skin, catching the flange of the disks.
I drilled out the outside skin, exposing the disk flange then welded them up. This was a bit tricky as the disks
are not square to the outside body -- cocked -- which probably made it more likely to eventually work loose.

FrankensteinScar.jpeg (362.47 KiB) Viewed 3079 times

Welded the access cover back on, and didn't bother to "pretty it up" with a grinder, Frankenstein scars OK

Back on the rig and FINALLY no damn rattle, in fact quieter than ever.

I think the OEM and 2'nd party mufflers are similar construction. I need to get the right shielding gas before I
open the Stainless steel muffler and see if that's going to need a similar fix.

[mm58]

If a person knew right where to drill, I suppose the same fix could be accomplished by drilling thru the skin and disc flange, then welding up the hole, thereby bonding the two together.

Mike
'76 710K

Sent from my SM-G930V using Tapatalk

[ChickenPinz]

You could probably also drill and pop-rivet instead of welding for those without welding equipment and skills.

I'm also wondering if a person could accurate locate the plates from the outside by tapping or some other means to avoid the large surgery. Worst case a small hole in the end and an inserted piano wire as a depth gauge, then a rivet/weld/sheetmetalscrew in the probing hole in the end.

Thanks, for that great info!

<I'm saving this thread...just in case>

[Hugues]

Thanks Ron for the open heart surgery pics.
Now it's easier to imagine a less invasive way to do this from the outside.

[ChickenPinz]

I've been pondering ways to identify where to weld/rivet from the outside. Below is an image from a thermal camera, which looks promising.

Probably the small hole on the end with a piece of piano wire is the most direct, though.

Xinf_241103_142330_440.jpg (422.57 KiB) Viewed 2997 times

[Hugues]

I've been pondering ways to identify where to weld/rivet from the outside. Below is an image from a thermal camera, which looks promising.

Probably the small hole on the end with a piece of piano wire is the most direct, though.
Xinf_241103_142330_440.jpg

That's clever! Clearly thinking out of the box here.