Made a propane tank muffler today

[Tom]

Wow did that cut in the noise!  What I did was take an old 20 lb cylinder and drill a 1 3/8" hole in the top and and side near the bottom and welded in a couple of 1 1/2" pipe couplings. On the bottom coupling I welded an extension into the tank made of 1 5/8 fence tube with a bunch of 5/16" holes drilled in it. I capped it with the plug from the hole saw. To connect I used an 18" length of 1 7/8" flexible muffler tube.

I can't even hear the exhaust note over the engine noise unless I'm standing right in front of the tailpipe. Right now this is being used in my temp location, however it will eventually be set into the engine room slab to facilitate the underground exhaust.

[Tom]

Now I need to deal with the diesel knock and intake noise. I might try retarding the timing a bit and see if that helps.

[clytle374]

Now I need to deal with the diesel knock and intake noise. I might try retarding the timing a bit and see if that helps.

I might do the expansion tank, cheap and KISS.  Might try it on the intake noise also. 
But I find diesel knock soothing to the soul.

[oliver90owner]

Tom,
You wrote; 'diesel knock'.

What fuel are you using?  Perhaps some, or more, veggie would help?  A lot say it does.  Try a cetane rating improver to see if it changes?.  Run it with a little ATF in the fuel for a couple hours or so, as an injector cleaner? Perhaps record audio before and after, on exactly same settings, to be able to decide afterwards? (less subjectivity).
Then there are other things like a little propanone (acetone) in the fuel (be aware of fuel pipe absorption).

That KISS principle is great.   When someone complains it didn't work so well for them, you may have to be more prescriptive as to exactly where you cut the holes and how far the pipes were inserted into the cylinder!!

Regards, RAB

[Tom]

I'm currently running a 50/50 bio/red diesel mix. I didn't reset my timing after adding an offset idler bolt so I am thinking that with less slop in the system I may be running a bit advanced. I may be carboning up a bit as I was running a 50/50 wvo/bio mix over the summer and had light loading too. I might give the acetone a try. The Ashwamegh comes with chromed steel fuel lines so no problem there.

[hotater]

This one is now 10 months old and is still huffing along.  The holes are equivelent to the pepper can original and on the downhill side of the tank so it doesn't funnel rain and snow.

The two inch cross pipe is cut away with two wide Vee notches facing upward with a couple drain holes coming out the bottom.

BE SURE to remove the steel slugs from the hole saw!!  Mine jangled and clanged on every throb until I dropped in some big magnets.
  Now, they just turn loose late at night and clang a while to give me something to worry about.   

[rcavictim]

This one is now 10 months old and is still huffing along.  The holes are equivelent to the pepper can original and on the downhill side of the tank so it doesn't funnel rain and snow.

The two inch cross pipe is cut away with two wide Vee notches facing upward with a couple drain holes coming out the bottom.

BE SURE to remove the steel slugs from the hole saw!!  Mine jangled and clanged on every throb until I dropped in some big magnets.
  Now, they just turn loose late at night and clang a while to give me something to worry about.   

Someone`s a pretty good shot!  222`s?   

[Tom]

Hey Hotater,

I made mine with a bottom outlet because I plan to use it as part of my underground exhaust. I can run underground about 15' and come out the side of the hill below the house. Since I made a threaded outlet I can use it now and run the exhaust out the door of the storage area where it is temporarily located until next spring when I can start on the genny shack.

[MacGyver]

Well, I made a propane tank muffler today too. It's amazing how much it quiets things down. I just screwed the original pepper pot muffler into the outlet of the propane tank for now but I'll add an automotive muffler to it later.

An interesting side effect is that it made my neighbor quieter too. He was hanging around jabbering in my ear and wouldn't take my subtle hints that I had stuff to do.
As soon as I whipped out the plasma torch and an old propane bottle, he suddenly realized that HE had other things to do and quickly disappeared. 

[rbodell]

As soon as I whipped out the plasma torch and an old propane bottle, he suddenly realized that HE had other things to do and quickly disappeared. 

Of course if you wanted to have some fun you could have brought out a full bottle, cracked the valve for a few seconds and said "AHHH heck, well, there isn't much in there"

[Stan]

Has anybody found that a solid exhaust pipe is quieter than using flex tube?
Stan

[Tom]

Hey Steve looks good. I guess since everything is bolted together you don't need an vibration isolator. Did you put any baffles in the tank?

[MacGyver]

Nope, no baffles.  I'll add a muffler downstream.

[greasy_burger]

What do you need to prepare the propane tank for welding(to clean out of fumes etc..)

[Stan]

I wash them out with soap and water several times, to cut down on the horrible smell (forgot the name of the chemical that makes the smell) and then when I'm ready to burn or drill into them, I fill them right full of water and leave it in there while I drill or burn.  That way the "fumes" will have been driven out by the water and you will be positive you won't end up in the local burn unit.

I have heard others fill them up with CO₂, or exhaust to achieve the same purpose but I like water.  I know it won't explode on me (unless it's in a sealed container and heated, of course)

If you want to burn a hole in the bottom with a torch, you have to fill the tank with water, put the fitting back in, turn it upside down and then drill a couple of holes in the bottom where you are going to burn the hole to relieve any pressure from the water boiling when you apply the heat.  Watch out because if you drill too small a hole, when you start to burn you might get a jet of steam in the face.

You leave the top fitting out, of course if you are going to drill or burn from the top.
Stan