Butler Silencer Lessons Learned

As you know, I have been dealing with a silencer issue on my old Butler.  I purchased a great rust-free used one....that didn't fit the chassis.  Then I purchased a used one that Saiger found me....right one, but also rotted and needed repair.

Over the weekend, I decided to repair the second silencer.  The plan was to just "re-skin" the body with really thin metal to give me another year or so of service life.  The problem fell apart quickly as I kept blowing holes through the box due to rotted metal, there just wasn't much left of the factory metal left to weld to.

So, I ripped it apart, cut new panels, and welded up a new exterior skin.  The original used thin metal, I didn't.  I went with 1/4 steel plate to get some longer life out of this box.  It did add another 30 lbs to the project, but maybe it will also give it a deeper tone.

What concerns me is one thing.  Inside the factory box was some kind of wooden layer....odd, but it didn't seem like it was really an insulation layer, more like they made the box out of plywood and then welded the box around it.  Maybe they did, I don't really know, but I didn't replace that.  Hopefully, I don't end up with a bad plate reverb as a result, but I was afraid of screwing up the flow if I stuffed steel wool packing inside, so I didn't use anything.

I guess I will find out if this was also a mistake this week.  The present muffler is just a tin muffler that gets me 89 db, but with a high pitch to it.  IF this box only did the same 89 db, but with a deeper tone, I will be pleased.

It's probably the wood that gives it that deep tone.

I have to get something for the TNT. The blower is loud and I know is jacking up my hearing even more than it already is.

Nice job!.......what you made looks great, and I bet works well to.

1Mine was also pretty bad and hard to weld with my wire feed being also very thin and easy to burn holes threw. So I ended up making a much bigger patch piece than just the rotted out area, so it would wrap around far enough so I had solid to weld to. So far so good.

But wow, 89 is pretty loud, especially when the pitch is high. I also think you'll get a lower pit1ch out of the heaver gauge material1. AND the lower deep bass tone can make a Huge difference all by itself!
I learned that on my quest to quiet mine down, where I only lowered my Db down about 10 points, but got a much deeper note out of it, which made a huge difference!

Hopefully you'll have the same results.

My TNT with the standard auto muffler is at 90 db, but is far easier to tolerate due to pitch. I'm optimistic that things will be quieter, just not sure by how much.

I'm actually thinking about building a box for the TNT muffler to help isolate the noise. Something hinged like a suitcase with steel wool packing inside. That would make kind of poor man's silencer ala the Mafia.

Thrush makes a welded turbo muffler with packing Mo that is pretty thick and should make a big difference over the standard muffler. I picked one up and will be giving it a try.

That steel wool type 1muffler packing is what they use on race car mufflers. It's what I planed to use when I was thinking about making a silencer out of an RC99 filter, but never tried it.

Is there a wrap that can be used on an existing muffler that can quite it down?

Yeah let me know if its a big improvement over the stock muffler Rob

The wool makes sense to me and probably what I should have done, but this silencer box is actually dual chambers and uses the drop to slow the air and reduce volume. If I fill that space, it might make things worse.

I just found that thatched wood stuff very odd in the cavity. I just can't see how it helped anything other than holding moisture and causing rot. It looked like it might have been cedar even.

IF I had more time, I would have sprayed the metal with some line-x or something to reduce metal resonance, but I'm a carpet cleaner and have no patience.

Yea that wood sounds weird, not something you'd1 expect to s1ee in a muffler or silencer.

This is what it looked like.  Almost a cedar thatch...all busted up now.

Wow, that is some weird packing almost like a basket weave.

Found this claim on a site that installs thatched roofs.....interesting??

An added benefit is that thatch is a much more effective sound insulation than fiberglass. An inch of thatch will stop a microphone from picking up sounds.

Amazing info on Thatch, might make a nice recording studio.

Mo wrote:Is there a wrap that can be used on an existing muffler that can quite it down?

Yeah let me know if its a big improvement over the stock muffler Rob

Thrush welded is definitely a deeper tone.

http://www.thrushexhaust.com/products.html

A little update:

The silencer has been installed. It was a pain in the butt trying to manipulate a 140 lb metal safe into a tight position and install the hardware. To add to it, the stub pipe from the blower had to be cut to remove the muffler that was previously installed....I butchered it with a sawzall and left the cut at an angle as a result.

These units aren't welded in place from the factory, they just run the pipes up against each other and cover them with a sleeve of marine exhaust hose.

In my case, I had a 1/4 inch gap on one side due to the angle cut and the space was too tight to try and get in there to level it out. I also couldn't locate any marine hose local.

I ended up using a sleeve for a turbocharger piping. It was rated for 1500 degrees, but I didn't know how much psi it could handle before blowing out. That made me worried, plus it wasn't going to insulate sound much.

Next up was wrapping the entire elbow with racing header wrap over the sleeve and them I used a muffler band clamp over the location of the two pipe ends. It looked pretty good, so the next step was firing it up.

Today was that day.....the results were amazing! It was funny, when I covered up the vac hose to activate the fast idle pod, I didn't notice the ramping up of the engine idle and thought there was something wrong with my machine....nope, it was ramped up at 3500 rpm.

By the numbers using my sound meter:

GMC Savanna van (5.7 Motor) at 3500 rpm.......80 db
Butler and van both running at 3500 rpm..........82 db

It doesn't get much better than that boys and girls.

Mark Saiger...what does your butler run at sound-wise? I am curious if this extra plating made that much of a difference or not.

Wow, that is very nice, your numbers sound great.  And I know that without that high pitched note from a stand alone engine, the deep 80 db is nice and quiet!

Good job mil you rock! Can't wait to hear how my decibels read.

milspec6 wrote:A little update:

The silencer has been installed.  It was a pain in the butt trying to manipulate a 140 lb metal safe into a tight position and install the hardware.  To add to it, the stub pipe from the blower had to be cut to remove the muffler that was previously installed....I butchered it with a sawzall and left the cut at an angle as a result.

These units aren't welded in place from the factory, they just run the pipes up against each other and cover them with a sleeve of marine exhaust hose.

In my case, I had a 1/4 inch gap on one side due to the angle cut and the space was too tight to try and get in there to level it out.  I also couldn't locate any marine hose local.  

I ended up using a sleeve for a turbocharger piping.  It was rated for 1500 degrees, but I didn't know how much psi it could handle before blowing out.  That made me worried, plus it wasn't going to insulate sound much.

Next up was wrapping the entire elbow with racing header wrap over the sleeve and them I used a muffler band clamp over the location of the two pipe ends.  It looked pretty good, so the next step was firing it up.

Today was that day.....the results were amazing!  It was funny, when I covered up the vac hose to activate the fast idle pod, I didn't notice the ramping up of the engine idle and thought there was something wrong with my machine....nope, it was ramped up at 3500 rpm.

By the numbers using my sound meter:

GMC Savanna van (5.7 Motor) at 3500 rpm.......80 db
Butler and van both running at 3500 rpm..........82 db

It doesn't get much better than that boys and girls.  

Mark Saiger...what does your butler run at sound-wise?  I am curious if this extra plating made that much of a difference or not.

I've never done a decibel test, but there are very quiet compared to a lot of other TM's

New Muffler boxes are also Stainless....nice stuff now

I've seen the new boxes and glad to see butler realize the need for the stainless. I just don't remember my butler ever being as quiet as it is right now...even new with the carbon steel box.

It has me dancing in the street!

milspec6 wrote:I've seen the new boxes and glad to see butler realize the need for the stainless.  I just don't remember my butler ever being as quiet as it is right now...even new with the carbon steel box.

It has me dancing in the street!

Got to love that