2nd Gen Non-Engine/Transmission Noise reduction effort update

[Lsfarm]

Accronym

Hi CM. HVAC stands for Heat Ventilation Air Conditioning.



The place I'm refering to is the area under the windshield wipers and the plastic grill at the base of the windshield.



There is a bare, painted metal trough, like a giant rain gutter under there, that picks up and passes on the engine noise to the cowl under the windshield and into the defroster ducts. This is a major source of the engine noise that seems to come through the windshield.



In front of the passenger is the HVAC intake, in front of the driver is a big empy cave of bare metal, which acts like an echo chamber for the cummins clatter.



I filled this 'cave' with rolled up foam to end the echo. I lined the passenger side with foam to deaden the clatter. I still get some turbo whine into the cab though.



Automotive performance stores sell a fiberglass tape to wrap headers with. GSI sells a similar product. This wrap takes some of the tinny sound out of the engine.



Greg L The Noise Nazi.

 

[vc]

Acoustiblok

Acoustiblok Sound Insulation



I just saw this promoted in a boating magazine I get. Made for the engine rooms of boats, claims that it is waterproof,oil and grease resistant, very flexible, easily cut and looks like a thin sheet of rubber-like fabric. Can be stapled or glued into place. They claim that once in place, it reduces sound transmision by 26db. They also mention that lead only reduces 20db. . Also says it's UV resistant and surpasses UL94 burn tests



Sounds interesting to me.

vc

 

[GGibson]

LsFarm

Thanks for your advice. I would guess that 3 sheets of 4x8 foot lead might do the job or should I go for 4 sheets to cover the 2 layers on passenger side?



What is the best souce of Lead Sheets these days. I have the Canada info from previous posts.



Re. you comments about the HVAC. On the drivers side you mention you stuffed the "open can" with the foam. Do you access this open can by taking off the grate that is just under the window on the outside of the truck or do you access it from inside the truck?

 

[Lsfarm]

Lead sheet

Hi GGibson two sheets 4'x8' will be plenty for the cab with two layers on the floor. The neat thing about the lead sheet is that there is very little waste. Even a 3" square piece can be glued on a bare spot and be usefull and functional.



Get a small roller or use the button end of a craftsman screwdriver to mold the lead to fit the surface to be covered, then apply regular yellow contact cement, and apply the lead while the cement is wet. This allows you to position the lead where you want it. Roll or mold into position again.



I see you live in California, [ land of red tiled roofs], Lead sheet used to be used under the tiles on those roofs, check with a roofing wholesaler to see if it is available locally. Shipping lead is expensive.



The only way that I've found to access that hollow 'cave' in front of the driver is from under the plastic grill at the base of the windshield. Remove the wiper assembly, and you will have two holes that you can get your hand/arm into. WARNING: the edges of the metal are sharp! Put a layer of duct tape over the edges to prevent shaving your arm, or slicing your fingers!



I glued a foam liner to the inside of the 'cave' first, then later just rolled up a piece of foam and stuffed the entrance to the 'cave' full. I think both together are quite effective.



Hope this helps, Greg L. The Noise Nazi

 

[GGibson]

JC Whitney

I've seen two partnumbers for JC Whitney in previous posts:

12ZX69333

15ZH8486W 1/2" 6ftsq.



Has anyone determined if this is really the same as GSI 1/2" foam?

 

[GLASMITHS]

GSI - JC Whitney

Yes they are the same. That is the 1/2" foam with barrier, and also they have some Dynamat type material that is the same. I do not know if the thin stuff is the same. I have boxes of both from JC and it has a GSI stamp on box. Also, Greg (Lsfarm) was at GSI and saw boxes with JCW on them. Probably what they do is drop ship.

 

[GGibson]

GSI-JC Whitney

Thanks for reply

Could you tell me exactly which part number is like the GSI? I just can tell from their pictures and descriptions. Thanks for your help.

 

[dflack]

joining the quiet club

OK, I'm getting ready to tackle the noise - 3 comments/questions-1. How thick(what weight) of lead is recommended?

2. Greg, you're the bandleader here... have you had the opportunity to check with your contacts at GSI to attempt to lower direct pricing (TDR) to less than through JCWhitney...

3. Anybody in the North Texas D/FW area planning this project... any chance of combining an order to get better pricing/shipping from GSI and/or suggestions on a source for lead sheeting? I hope to get to Bic's Coffee shop next Saturday and will ask whoever's there too...

4. Finally, I don't see much talk in this thread on noise coming up thru the gearshift... suggestions? I would think the best time to be working in this area is when I have the seat/carpet out.

 

[Lsfarm]

questions

Hi Dflack, no I haven't had the time to call GSI, but I'm sure that if you mention that their price is not as good as going to JCW, they might at least match it. If not, just order from JCW. GSI will get the message.



I do know that they ship to JCW by the truck load, I've seen the stack of boxes. So it may be a bit more work for them to handle our little orders. Hence the slightly higher price to us. But I should hope by now that the volume of orders from the TDR is large enough to get an additional price break!!



The lead sheet I use is 2# per sq. ft. about 1/32" I think. There is a 1# product, but I haven't heard of anyone using it



There is a lot of noise coming up through the gearshifts, I have a piece of GSI foam under the carpet with a slit, [not a slot] cut in it. The foam forms around the four wheel drive selector lever. In a stick shift truck, any effort to create a foam layer between you and the trans will be helpfull.



The gearshift lever itself has a rubber isolator in the base. I've never done it, [I have a DTT automatic] but try a piece of the grey pipe insulation foam and wrap around the shift lever itself, and see if you can hear any difference. This will be a truely ugly application, but if it is effective, you could install it for long freeway or towing trips and remove before anyone else can see it!



You can pull up the gearshift boot/console/cupholder with a few screws, and add some foam or other carpet insulation around the shifter without having to pull the full carpeting up.



I hope this helps. Greg L The Noise Nazi.

 

[dflack]

Thanks Greg

Greg, thanks for the additional info. Any decent roofing or masonry supply carries 1# lead for flashing, I'll check around for 2#. My experience with lead forming is to have a propane torch around to "warm it up" a bit to work any tight curves, but let's be careful out there folks!



Finally, I can't help myself but to ask the difference between a slit and a slot... . I guess that just shows I'm a beginner here! No reply required.

 

[Lsfarm]

Difference: A slit or a slot?

I knew that would get a reaction! A slit has no material removed, and closes itself up after the lever slides past. A slot has material removed and has an opening letting sound through.



The lead sheet is like cloth in the 2# weight, it didn't need any heat applied to mold it around lumps or into crevases. I cut it with a pocket knife like paper or thin cardboard. Kind of fun to work with actually. Unlike the stick on b-quiet or dynamat which gets stuck to itself like tape or flypaper. Of course this might just be because I'm all thumbs.



Greg L the Noise Nazi

 

[Hohn]

sheetblok

Vaughn, I was thinking of the Sheetblok more for the floors and horizontal surfaces.



Dynamat or the GSI sticky stuff would prob be best for vertical surfaces, and then just put the GSI foam over the top.



HOHN

 

[GGibson]

Lead Supplier-Southern Cal.

I found a great source of Lead Sheet



Industrial Lead

10332 E. Rush

South El Monte, CA 91733

323-283-7611

323-283-7613 (FAX)



I was quoted $160 plus tax for 4' x 16' x 1/32" thick

This includes the cost for 1 cut to 16' because they have to roll out 4'x25'. More cuts will add cost. They will roll it up into a 4' length that you can "pick up" (should weight about 130 lbs. )

You can make the call, pay by credit card and the roll will be ready the same day for pickup.

 

[GGibson]

Lead Supplier, WI

Got this info re. lead supply:



. 031" x 28" x 128 square feet (235 pounds)@ $1. 44 per pound FOB Milwaukee

Steve Gamel [sgamel@vulcanlead.com]

 

[illflem]

Why lead???

Pardon my opinion but what are you guys doing, trying to block X-rays!

I know very little about sound insulation except in a recording studio I helped build, didn't see any lead there. Seems like dead air space is the best insulator and that a man made material would do much better job than lead without the weight and expense. Please correct me if I'm wrong.

 

[Lsfarm]

Adding mass

Hi Bill, the lead is glued to the thin, tinny back wall, floor and door skins to add mass. The heavier the barrier between the source of noise and our ear, the less noise is transmitted through to us.



Think of it like this: the sound is energy, it takes less energy to move a light object than it does to move a heavy object. So if we have a given amount of sound energy, more of it will be absorbed trying to vibrate a heavy barrier than a light thin barrier.



In homes, if you want to make a room quiet, builders often use the much heavier green board instead of regular white wallboard, or use two layers of white wallboard to block sound transmission. Ever notice how much sound gets through those cheap cardboard hollow doors compared to a good solid core door in a house or office?



Two walls completely separated by an unbridged gap will also transmit less sound, like in your sound studio. But that would be difficult to duplicate in the cab of our Dodge trucks.



We [the Quiet Cab Club ] have found the lead sheet to be a fairly economical and easy to apply product to add mass and reduce sound transmission.



The back wall of my truck cab sounds almost like wood when I thump on it with a knuckle, a stock back wall sounds like a tin can.



Hope this answers your question Greg L. The Noise Nazi

 

[GLASMITHS]

Pardon my opinion but what are you guys doing trying to block x-rays?

 

[Forrest Nearing]

heh, this is cool... I happen to have a good friend who owns one of the largest lead suppliers in the area!



quiet cab here I come!!



yellow contact cement? as in liquid nails?

 

[Lsfarm]

Contact cement

Hi Forrest, man you are lucky, I had to pay a dollar a pound to ship my lead sheet from Montreal to my home. this doubled my overall cost.



The contact cement used is just plain old contact cement in a can, applied with a brush. But like I said in an above post pre-form the lead sheet, apply the contact cement, and apply the lead sheet wet, this allows you to slide it around and position it the way you want . This is what what worked best for met. [and Goober, the original user of lead sheet]



Don't try to work with too large a sheet of lead, unless you have a second set of hands.



Let us know how this works out.



Greg L. The Noise Nazi

 

[Forrest Nearing]

defintately will report back...



one little thing... I don't own the truck yet!



going to pull the fan/idler to check for a cracked timing case this evening. if all is well, I should take ownership before the weekend!!



Forrest