Hanging mufflers

[phat46]

I am in the process of putting the mufflers under my project truck to day. It looks like they will have to be less than an inch from the floor. Does any one have experience will mufflers this close to the floor? I.E. what type of insulation did you use? Did you put it inside the vehicle, or on the outside under the floor? How about the stuff you wrap around the muffler itself? Any advise would be helpfull.

[enjenjo]

The stuff called lizard skin, that you paint on works good in this type of situation, also Dynamat has some stick on insulation that works good too.  In my experience, 1" is not too bad, although I prefer 2" or more. There are several products that will do the job.

Muffler wraps are ok, but I don't like the way they look, my opinion only. I would insulate the floor instead, maybe with a heat shield mounted under the floor.

[phat rat]

Bad thing about wrapping exhaust is that it'll hold moisture and promote rust. Did that with the first set of headers on my cpe and they only lasted 3  summers

[Charlie Chops 1940]

Although your question was about distance from the floor I might add that it is well worth your time and effort in fabricating some rubber or poly mounted cradles into which to clamp the pipes and/or mufflers. They tend to more solidly locate the system and you don't need hanger room in already tight confines. It's not easy but with some thought I think you'll be real pleased.

Charlie

[Bib_Overalls]

This picture shows one of the exhaust mounts my friend Rick Walker fabricated for his Model A coupe.  Simple is elegant.  A 3/4" ID tube is welded into a crossmember.  A short length of hose provides the cushon and a little flex.  There is room to accomodate heat induced expansion and contraction.

[phat46]

This picture shows one of the exhaust mounts my friend Rick Walker fabricated for his Model A coupe.  Simple is elegant.  A 3/4" ID tube is welded into a crossmember.  A short length of hose provides the cushon and a little flex.  There is room to accomodate heat induced expansion and contraction.

That's close to what i have come up with to hang mine. I had to replace the entire floor in the cab so i built a subframe of 1" X 1" tubing to attach the floor and trans/driveshaft tunnel to. Of course nothing lined up over the mufflers to hang them from, the tubing is spaced at less than the length of the mufflers, so i decided to use a piece of 3/8" rod bent to line up with the offset inlet and outlet of the mufflers and welded to the subframe tubing. From the rod i will use the "universal" muffler hangers from a Auto Zone type store. They are simply a rubber strap with holes in it and a small metal piece at one end bent at a right angle that goes under the muffler clamp on a pipe. The holes in the strap are 3/8"  so I cut the straps to the proper length and slid it over the bent rod which i made long enough to go past each end of the muffler. Just slide the strap till they are over the inlet and out lets of the muffs and clamp them to the pipes. This also gained me another quarter inch of clearance from the floor.  

[phat rat]

The way Charlie recomended works great. It's the way we did my cpe when building it. After 30,000 mi it's still trouble and rattle free.

[flt-blk]

When you build your mounts, take into account the exhaust will move as
it heats up.

As long as you plan for this you shouldn't have any binding.

[phat46]

When you build your mounts, take into account the exhaust will move as
it heats up.

As long as you plan for this you shouldn't have any binding.

Yup, the muffs will be hanging on rubber straps from the mounting rods

[Leon]

It costs a little more, but the coatings like Jet-Hot and some of the others can be applied to the muffler to cut down on heat radiation.  While the silver stuff looks good, the darker coatings have less aluminum in them and do a better job of insulating.  The muffler won't rot out like the wraps cause, and it will last longer too.  Lizzard skin on the floor completes the job.