Sound deadening an m915a1- phase 1

I want to make my M915A1 as quiet as possible. I plan on doing this by adding sound deadening in stages. The first stage was the floor section of the cab. I used regular household 6" thick fiberglass insulation against the floorboards and then covered it with a 1/2" thick aluminum foil sheeted sound deadening bat. To hold it in place, I fabricated an angle iron skeleton that was wedged(and then bolted) into the frame sections of the cab so that the insulation was squeezed between the floor and the skeletons.

This was one of the hardest and most miserable jobs I've ever done. It takes hours to fit the insulation and get it in straight and not crumbled. It took two full days. I didn't take sound readings, so I'm going by ear, which can be deceiving sometimes. The end result was that the truck was quieter, but not a huge difference. For the amount of effort involved, this was not the correct way to do it, I think I could have come close by putting another foam rubber pad on the floor and then covering it with a thick hard rubber fitted floor mat. I doubt my way would hold up well in rainy weather as water might soak the insulation and make it sag, but I intend to use this truck only on sunny(summer) days. The truck is much cooler now and all the gear train noise is gone. The turbo and engine combustion noise is much more noticeable which means that they are now the loudest contributors to overall noise.

My next phase will be to insulate the inside of the doors, behind the dashboard, and the inside firewall with foam and heavy rubber. This probably won't be until the end of summer though. It's funny, the tractor is faded 383 green and the painted skeleton is 383 also. In real life, the colors are not too badly matched, but in photos they appear like completely different colors. Same with the trailer.

that does look like it sucked, they do make a spray on product called lizard skin that is supposed to be the cats meow for sound deadening. I plan on spraying the interior with it when ever I get the motivation to rip it all out.

Big job any way you do it.

I have used dyna mat and regular auto carpet insulation in a few CIVI trucks and I was very pleased. Great job on the install. It might even be a few more degrees if you paint it Tan..Joke, looks good..

By compressing the fiberglass you negated most of the insulation value although you may have quietened it down some. It will hold water and turn into a mush when it gets wet.

I vote for the Dynamat or other such materials sold through hot rod sites.

I know the military had a sound deading mat because I bought a butt load from GL one time and it sold like hotcakes.

Compared to other MV's I find the M915 to be quiet enough so that I can live with it.

Sound deadner

Gents .......my vote goes to "LIZARD SKIN"...this stuff is bad azz!!! falls under the heading of "try it,you'll like it"popacom.

I agree that the fiberglass will hold the water.

Commercial trucks use a pad under the rubber floor mat.

You should put the insulation inside of the cab to protect it from the weather so that you do not end up with rust issues.

The hot rodders have some good stuff that works.

DB Engineering makes floor mat material, cab insulation materials, metalized mylar insulation, adhesives and special fasteners that are same as OEM stuff used by others or better.

Cab Insulation

Thanks for the information and link on DB engineering.

I have already requested samples for one of my projects

I have been going though this on my 1940 Plymouth truck. What I have found is that Dyno mat is a huge waste of money. It works great but it is way to expensive. A good friend of mine found out that dyno mat is the same as Snow and ice membrane. Not the stuff with the sandy finish, but they make one that is heavier and smooth like dyno mat. Also there is a guy on the H.A.M.B selling a sound deadning/fold insulating material. I was told it is cheap and works great. Check this topic on the H.A.M.B there is a wealth of info there too.

I just checked the price per square footage and the lizard skin is 1/2 the cost of Dynamat.

A roll of snow and ice is 3x50 and cost about $70 bucks. If you want some real heavy stuff check out Bituthane weatherproof membrane. I have used it before. Once it is on it doesn't come off! I haven't bought it in a while, but I think it is 3x50 for $100 a roll. Don't think lizard skin can come close to that!

WOW nice job but holy cow that looked like it was painful. On my Deuce I used a product called FAT MAT, its another version of dynamat I think it all works pretty darned good, I also rhino lined the entire inside of the cab and floor then used 1 inch tractor cab insulation over that, I can now at least talk to a passenger while going down the highway! Lots of work you got going on here but I bet is nice in the end!
KK

the fatmat is a great product. dynamat is equal but has better adhearing for roof type work. that being said. alot of the mat is in the way you apply it. it should go over any bracing and touch the panel on both sides. more than 1 layer also works well. it is used extensively in the car audio world which is where i was introduced to it. rhino liners is also doing roughly the same thing as the mat. it's about the resonance properties of the metals. i plan to fat mat x2-3 layers the firewall, floor, doors and rear of cab, dynomat extreme x 1 layer on roof, and rino or similar type lining of floor,firewall, and rear of cab. but that's all after a cab extension or possibly a double cab, not sure yet which is the way of the sword.
ken