Adding a 2nd muffler on a JD 790

   / Adding a 2nd muffler on a JD 790 #21  
Changing mufflers, adding mufflers, etc. seems like an extreme, and expensive way to reduce noise.

I have shooting ear muffs as others mentioned which I wear with my Kubota B3030 cabbed tractor and for loud stuff (running log splitter, wood chipper, mower and chain saws, I put ear plugs in my ears as well (double protection). I have a box of 500 pairs of those. It keeps the sound level quite low.

At 61 and hard of hearing I can ill afford to lose any more.
 
   / Adding a 2nd muffler on a JD 790 #22  
Thanks Pat, I "was" aware of the vibration dampners and intented to add attitional as what's on the genset are probabley minimul. This genset will come out of an RV that I will be scraping next year. This genset also weighs in at about 300lbs. I'm also considering converting it to propane. I've got some ideas on how to baffle the intake/exhaust air to minimize noise. This thread has enlightened me with some additional information that I had thought about but didn't know how I was going to handle.

Thanks.
 
   / Adding a 2nd muffler on a JD 790 #23  
Thanks Pat, I "was" aware of the vibration dampners and intented to add attitional as what's on the genset are probabley minimul. This genset will come out of an RV that I will be scraping next year. This genset also weighs in at about 300lbs. I'm also considering converting it to propane. I've got some ideas on how to baffle the intake/exhaust air to minimize noise. This thread has enlightened me with some additional information that I had thought about but didn't know how I was going to handle.

Thanks.

Didn't want to come across like you were retarded, just tossing in some considerations. I have seen so many failed installations due to mismatch in the weight rating or frequency band (RPM of rotating equipment) of the anti-vibration mounts. Good performance when matched and poor performance when not.

Stroll down memory lane... Naval weapons platforms (AKA ships and boats, to include subs) come out of a major refit/overhaul pretty quiet and then start getting noiser and noiser over time. Sailors paint over braided ground straps and rubber anti-vibration mounts which renders them more and more ineffective as coats of paint build up.

Good luck on your project. I have a gas genset out of a motorhome I donated. The cooling fan was mounted on an extension of the crankshaft. The shaft failed and the fan end fell off. Engine runs fine and generator generates but I will have to hook up an electric fan to supply cooling air. I thought of adapting it to propane as well and buying an aftermarket controller to make it into an automatic standby generator but... I decided to just buy a fully automatic packaged unit (Generac Guardian or whatever) set up for LPG.

Pat
 
   / Adding a 2nd muffler on a JD 790 #24  
Changing mufflers, adding mufflers, etc. seems like an extreme, and expensive way to reduce noise.

I have shooting ear muffs as others mentioned which I wear with my Kubota B3030 cabbed tractor and for loud stuff (running log splitter, wood chipper, mower and chain saws, I put ear plugs in my ears as well (double protection). I have a box of 500 pairs of those. It keeps the sound level quite low.

At 61 and hard of hearing I can ill afford to lose any more.

I find that muffs that fit tightly enough to be effective start to be painful if worn for an extended period. I will be buying a set of active electronic noise canceling headphones which will work better than typical shooting muffs. They act as music or radio headsets too. You can put in earplugs and crank up the volume to hear the radio and other sounds are really attenuated.

Pat
 
   / Adding a 2nd muffler on a JD 790 #25  
Nope, didn't take any offense at all. I go through a lot of thinking and planning but in the end I'll get in a hurry and forget many things. I'ts good to be reminded once in a while.
 
   / Adding a 2nd muffler on a JD 790
  • Thread Starter
#26  
I find that muffs that fit tightly enough to be effective start to be painful if worn for an extended period. I will be buying a set of active electronic noise canceling headphones which will work better than typical shooting muffs. They act as music or radio headsets too. You can put in earplugs and crank up the volume to hear the radio and other sounds are really attenuated.

Pat

Pat, I bought a set of Howard Leight electronic hearing protectors to use when I deerhunt. You can turn up the volume all you want, or way down if you want. The areas I hunt if I see a deer, I typically have time to put them on before I shoot. So, I don't usually wear them for a 3-4 hours at a time like during an entire hunt. Although, they do help keep your ears warmer! These were a highly rated product for the price and you can probably google the reviews on them. Here is what they look like but I ordered mine from cheaperthandirt.com

Howard Leight Impact Sport Earmuff

Sorry, but haven't learned all the in's and out's of this site yet and how to post pic's. I had some camo tape left over from when I did my truck and so I put camo on them:

http://i35.photobucket.com/albums/d170/kebo1957/DSC00791.jpg


Just for the heck of it, here's my truck, that's where most of the 3M camotape went!!

http://i35.photobucket.com/albums/d170/kebo1957/DSC00726.jpg


Anyway, I want to thank you and everyone else who has offered suggestions on how to make my 790 run quieter. I think I have decided to start off with this "plan of attack":

First, I'm going to get a cheapy decibel meter. I think that Radio Shack has one for about $40 so I can see if what I'm doing really has any effect at all. I can hold it next to my head while pointing it forward on the tractor while running it at maybe 2000rpm to get a *standard* reading for a baseline. That's probably about the speed I will run it most of the time anyway

The next step is to start with the stock exhaust pipe. I was looking at the pipe last weekend and the straight vertical exhaust pipe has a triangular shaped bracket where it bolts to the muffler. It's made a lot like the flanges on a set of headers are made. The JD 750 I used to have was made with the usual square bracket so you could rotate it to one of four different positions. Since I want to leave the exhaust original (knowing how proud JD is of their parts) I will see if I can find a muffler shop that will make me one for a reasonable price, only this one will turn straight down. I will probably try it about 18 inches long or so at first, and have it turned to face the front of the tractor to direct the sound away from me. I will then take a reading like that and see what kind of effect this has on it. If it helps, great!

If not, then my third step is to get some header wrap tape and try wrapping the muffler with it. I know you suggested to build a box around it and fill it with sand but I want to leave it stock if I can, and besides that sounds pretty involved and I don't have metal working stuff at my disposal anyway. After I wrap the muffler with maybe one or two layers, I will take another reading and see what that does. If it helps, great!

If not, then my next step is to try and get something to line the hood and side panels with. I will price the leaded foam like you mentioned first and see how pricey it is, assuming I can find it. If I can't find it, I did find some material at the same place where I found the header tape wrap. They say it helps dampen the sound some. Anyway, once I get the hood and side covers lined with *something* I'll take another reading and see what that does to it.

If it's still louder than I want, I will then try adding a 2nd muffler to the custom made down pipe and see what I can do with that. The only problem there is got to be careful with clearance for the FEL!! Anyway, this is something I'm going to work on over the winter and take my time with so don't expect real quick feedback from me on it! Thanks again!
 
   / Adding a 2nd muffler on a JD 790 #27  
I wonder if adding a second muffler or some of that lead wrapped bead stuff to my wife would quiet her down.... :confused:





It's really a good thing she doesn't read here, cause if she did, I'd be in twubble :D
 
   / Adding a 2nd muffler on a JD 790 #28  
I wonder if adding a second muffler or some of that lead wrapped bead stuff to my wife would quiet her down.... :confused:





It's really a good thing she doesn't read here, cause if she did, I'd be in twubble :D


"Richard" must have a very comfy couch......
 
   / Adding a 2nd muffler on a JD 790 #29  
.................
If not, then my third step is to get some header wrap tape and try wrapping the muffler with it. ............

The header wrap tape is pretty effective. We used to use it for diagnosis purposes when I worked on automotive exhaust noise issues.

You can also temporarily add an inexpensive second muffler in line with the original using some flex pipe just to see if it makes a difference. Direct the exhaust away from the operator for maximum attenuation..

Fiberglass would work as a liner to absorb high frequency noise like combustion and diesel cackle. One source is acoustic suspended ceiling tiles that are made from compressed fiberglass faced with a vinyl sheet. Discard the vinyl sheet.

You can also line any (cold) large sheet metal parts that may be reradiating the sound with an adhesive damping materiel. One source for this is the stuff they sell to repair gutters, or the roof underlayment used to prevent ice damming.

6 inch x 33 1/3 foot Roof Gutter Repair Tape - Aluminum 80520633SW by Protecto Wrap | DoItYourself.com
 
   / Adding a 2nd muffler on a JD 790 #30  
The sand lined box is very effective and doesn't have to be hard to make. You could just surround your stock muffler with say fiber cement board reinforced at all edges with drywall corner bead (thin cheap angle iron.) No mods to the stock muffler. Easy to prototype and cheap in case you don't like it. There is high temp caulk made for working around chimneys and flues which can be used to seal any cracks where the pipe goes through the box and may leak sand. Alternatively you can use the high temp silicone rubber from your FLAPS (Friendly Local Autoparts Store.)

I could make one of these and install it in way less than an hour. usning #8 or larger machine screws.

Pat
 

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