Rattling Mufflers on B&B

[Wbulk]

With less than two hundred miles on my car both mufflers rattle when the engine is running. I stuck a small LED flashlight inside to see what is going on. They have a perforated center tube that seems to be the problem. It has spiral perforations in a swirl pattern front to back. Interesting, the perforations on one side face forward, the other side face back.

Has anyone had experience with these. They may be Thrush brand by the description. It looks like the only way to fix them is to cut the mufflers out to get to the ends. Can they be fixed. It looks like the center tube slides.


Thanks.

[Dwight]

I would replace them with a pair of Cobra Pack mufflers from Classic. I have installed them on my Cobra and love the sound and performance.
Installed a pair on Hodge's B&B with a 408, two years ago. He loves them. Coach has a pair, so does Lainhart, both are big block cars.
Yep, we like our Cobra Packs!

Cut the old ones off and tig (or mig) the Cobra Packs on. Measure your old ones and order the same length. I bought a pair 4" longer and cut 3" out of my pipes to keep it close to the original length.
Longer mufflers are quieter. I need quieter, cops could hear me a mile and half at 6,000 rpms.

Has the mounting bracket broke away from the sidepipes? Most do.
Dwight

Classic Chambered Exhaust Inc. - Home Page

[Wbulk]

Thanks Dwight. That's a good option. You are always helpful.

[RET_COP]

Wayne, Dwight is right, get rid of them and buy the Cobrapacks. I copied the retrofit idea to a tee (this is the smooth transition reducer) and all worked very well. For holding tabs I use steel flat bar .125" X 1.50" x 6" and welded it from the bottom center of the muffler. The difference in height of that tab I just made up in rubber which also gives it some flex.
Now, what size? I kept the same length 24" and went with 3" ID. (This is a little overkill as the 2 1/2 will work well for 450HP as stated on the web site) My engine HP is in the high 400s. I faced the louvers toward the front and they were unpacked. To be honest my combination is loud. What I didn't realize is, the 3" ID alone will be loud, then add the unpacked and you get what I'm saying. I would say the 3"ID had the most noise impact of the two options. I found that I had 2 1/4 inserts in my original mufflers which I did not realize. After i did all my upgrades for HP from carburetor to primary headers including a cam, they were absolutely killing my exhaust flow and power.
The change for me was noticeable and I also had to re calibrate my carb
Central Connecticut Coatings did my ceramic coating and it was absolutely beautiful. They do most of the ERA's and Backdrafts
I'm happy with what I have and that's all that counts.

[Wbulk]

Good information Lou. It looks like that's the best option so far.

[Wbulk]

I went for a cruise with seven other guys on Saturday and the rattling at idle was driving me nuts. This was going to be a next winter project but it just couldn't wait. I just had to see what was causing this rattle that started in less than 100 miles on this car.

I set the R. side exhaust on the work bench and drew a line down the length of it with a fine line paint marker. I then propped it up with blocks and shims in three places and marked the sides of the three places on the blocks so I could recreate the alignment after it was cut apart. I used straight 1 3/4" pieces of paper wrapped around the pipes to mark for straight cuts where I decided to cut the mufflers. I cut them apart with a thin cutting blade on a 4 1/2" grinder.

As you can see the center section with the perforations is just welded in a few places around the edge. These are easily cut.



After the other end is cut you can drive the tube out with a piece of pipe. You can catch the inside lip and you only have to drive it a couple of inches to clear the end flange and then it just slides out.



Then you can drive out the end collar for the other side.

You can see how this goes together. The glass packing stays in the big case and the perforated tube slides in through one side, and the collar slides in the other. The perforated tube slides in the collar. Each is welded on the very ends and "where they slip together is the rattle point." All this work and all the company that made these had to do is reach in about two inches with a mig welder and weld the slip joint in a couple of places. Dumb, dumb!



I hope this helps others that may have this problem. I haven't decided to fix these or replace them. But it's an easy fix at this this point. I wish we could find out who made these.

Added:
Now that I know the problem, on the left exhaust side I just have to cut one end and reach in and mig weld the slip joint. This side needed to come totally apart because the perforations were facing in the wrong direction.