Anyone ever lined their MEP002/3 with Automotive Thermal Insulation Mat Material?

[johnray13]

I was wondering if any one has lined the inside of the sheet metal engine/fan/louver box enclosure of their 002 or 003 with automotive sound attenuating insulation. I have been looking at at roll of 1/8" thick, self stick, foil faced. I was thinking if you covered every possible inch of the (inside) metal covers, it wouldn't impact the motors performance, would be (visually) unnoticeable and could quiet things down a bit. The only negative is less heat radiation. But I don't think would be much of an issue.

It seems like it could make it a lot quieter...but I figured I'd run it up the flagpole here. Are there other things I am not considering

A few pics of what I am talking about:

 

[coxju04]

I took, my ASK completely off and tore out the old insulation, it was falling apart anyway. I then installed 3/4 rubber mat that I got at the hardware store. Put the ASK back on my 003. It did quit it down a lot. As for the Heat I've had no problems

 

[Ray70]

Hello Johnray. Are you talking about lining the engine/fan cover on a non-ASK machine? If so I don't think it would be worth your time and effort.
Simply covering the inside of the fan cover will probably do little or nothing towards reducing sound because it only covers the end of the motor. For any significant sound reduction you need to fully enclose the machine with a sound reducing enclosure. Adding new/better sound controll material to an ASK enclosure would be a much better idea.

 

[johnray13]

Yea, I' taking about lining the interior sheet metal of a non ASK machine. Seems like 99% of the noise would be coming from the motor end.
When it gets a little warmer, I need to pull my injectors. Since I will have to remove most of the metal to do that, I was thinking I might as well give this a shot.

I starting thinking about this at work. We have been building a lot of STC-50 offices and conference rooms lately using new technology, sound deadening materials (sound deadening drywall and doors.) On the doors, we have been adding a dense 3/16 rubber material to one side. I was quite surprised how much of a difference it made.

It got to thinking, if I did something similar to the 003, how much would it quiet things down?

If no one here thinks this is nuts, I may pick up a roll to have on hand when I pull the sheetmetal to do the injector service. Stay tuned...

 

[Hard Head]

I was wondering if any one has lined the inside of the sheet metal engine/fan/louver box enclosure of their 002 or 003 with automotive sound attenuating insulation. I have been looking at at roll of 1/8" thick, self stick, foil faced. I was thinking if you covered every possible inch of the (inside) metal covers, it wouldn't impact the motors performance, would be (visually) unnoticeable and could quiet things down a bit. The only negative is less heat radiation. But I don't think would be much of an issue.

It seems like it could make it a lot quieter...but I figured I'd run it up the flagpole here. Are there other things I am not considering

A few pics of what I am talking about:
View attachment 474577View attachment 474576View attachment 474578View attachment 474579

I used products from these guys and it is nice stuff.

http://store.secondskinaudio.com/how-to-insulate-your-ride/

 

[Ray70]

I've used similar material as well and yes, its great stuff, but for what you are trying to do I really don't think you will see much of any significant reduction in overall sound by just applying it to the fan cover.
You will only be covering 1 end of the motor , which in essence is a 6 sided rectangle. You will also still have the fan opening letting sound out of the one side you covered. I would say that 80% or more of the engine will still be exposed.
I think you are assuming that the rotating fan is going to produce the majority of the sound, but I think the majority of the resonating "Diesel" sound will be coming from the cylinders and heads which are still completely exposed, not to mention the exhaust.
I have 002A's with and without the ASK enclosure and I can say from experience that just running the ASK unit with 1 or more of the doors removed makes a huge difference in sound. Its almost as loud as no ASK at all.
It won't hurt to do what you are talking about, just don't be disappointed if the difference you hear is minimal.
The difference with the office space is that you are starting with an enclosed room ( like a generator with an ASK) and improving the sound transmission of the weakest point. Not adding a sound proof door to an open stall in the men's room. ( sorry for the bad analogy, but its what came to mind first )

 

[johnray13]

I get what you are saying, and agree with you for the most part. I am not trying to make this run "quietly", just quieter. Look at the pictures below. I plan on adding the insulation to not only the fan end metal but the "close to run" door and housing, the motor cover (cylinder shroud cover) as well as the air (louver) box and it's end closer piece underneath (shroud cover end piece).

I seems like a defect in the 002/003, that the military didn't use any sound absorbing material in places that makes sense to do it. On the other hand, maybe you are right and they also knew it (tested it) and it was like lining a bathroom stall door. In my stubborn mind, I still think it will make a noticeable difference.

 

[steelypip]

Most of the noise on these sets is from the fins on the heads and cylinders resonating to the 'Diesel knock' of combustion. Second loudest is probably the intake side of the cooling blower. You would likely derive some sound reduction from lining the cooling ducts with acoustamat, but the cooling air still will be exiting on the hot side and will be taking a lot of noise with it. The rocker box, and all exposed engine components are also resonators, and your duct lining will do nothing about that.

 

[95blklsc]

I made a number of improvements to the ASK on mine before installing it. There were really a lot of weak spots. Sometime I'll put up a post about what I did, but I can say it works very well. Since I put mine on casters, a big weak spot was the amount of sound coming out of the bottom. I closed that in with a sandwich of plywood and foam, with the inner layer of plywood essentially floating, just adhered to the foam. I added Roxul safe and sound insulation in many spots we well as sealing gaps with a dynomat type adhesive material.

Before the improvements I took a number of SPL measurements at different distances, and at different angles so I could really compare any SPL related improvements. I didn't complete the full measurements sequence again, but at 15 feet off of the right side with the set running at 61Hz I measured about 98-100 dB with an A weighting slow measurement. After the ASK install with my improvements I measured 69 dB under the exact same conditions, measurement location, and running speed. Most of the noise is now exhaust noise. I plan on added an additional mufflers and possibly a Helmholtz resonator pipe. I'd like to get it down about 6-10 dB, but that is a tough goal. These measurements are slightly higher than they would be in an open field. My house was about 20-25 feet away acting as a reflective barrier sending some of the sound towards my measurement position.

Here are a few pics of the assembly, ASK improvements, as well as some of the electrical install.

Full album link: https://plus.google.com/photos/1050...ms/5922725248166718785?authkey=CLKfr9PEpILxDA

 

[Ray70]

Wow! excellent work there 95blklsc, both mechanically and electrically, nice looking unit! That's what I'm talking about... you need a full enclosure if you plan to make any significant sound reduction. To further reduce your sound level from 69db by another 6 to 10db is going to be a monumental task, to say the least. You're talking about cutting the ( already significantly reduced ) sound level in half! I'd be very interested to see what it would take to reduce the sound further. My only concern would be to test the unit at full rated load for an extended period of time to be sure all the sound improvements don't cause any air supply or cooling problems when operated at full load on a hot day.
Good job!

 

[95blklsc]

Yea, I know it will be difficult reduce the output by 6-10dB. I like to set lofty goals. I still have a feeling that most of the noise that I'm hearing now is exhaust and cooling air related. I know I can improve the exhaust acoustics quite a bit. The cooling air would require a box with a couple of baffles and some acoustically absorbent material while still maintaining decent airflow.

So far the cooling capacity seems to be doing ok. I ran it in the middle of the summer (85F) loaded pretty heavily and the internal temps really only got just above 100F. There is quite a bit of air moving through the ASK. I also ran it with all of the covers open and it seemed to do very little to decrease interior temps. The cooling system has a few air leaks that spill to inside the ASK and it really keeps the air moving. It tends to blow some air out of the rubber flap over the throttle control. I have a low energy bluetooth temp sensor that I plan on sticking in the ASK to keep tabs on the temp during some of the monthly/every other month start up run for a couple of hours.

 

[steelypip]

The old muffler design rules still work for this. Damping volumes are odd multiples of the cylinder displacement with a minimum of about 7x for the primary chamber. You put the inlet pipe and the outlet pipe in at different angles/positions in the damping volume to cancel primary resonance modes.

Frankly, the easy way to muffle the intake is probably just to put a big tubular straight-truck muffler on it. The tubing diameters, pressure drops, and critical frequencies should all be close enough to work well.

I've also seen 20# propane bottles used with a center inlet and tangential outlet or vice versa. Be sure to mostly fill one of these with water if you go after it with a torch.