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Engine cover sound and heat reduction

Posted: Mon Jan 07, 2019 7:49 am
by Jake2015
Looking for advise and experience on the best materials to add to the underside and upper side of the engine cover to reduce both sound and heat. I have seen some products from Dynamat and other sound control companies, but would like to hear experience before ordering.

Thanks,

Jake

Re: Engine cover sound and heat reduction

Posted: Mon Jan 07, 2019 10:15 am
by TechMOGogy
viewtopic.php?f=17&t=10141
That sticky is a good read to start with

Re: Engine cover sound and heat reduction

Posted: Mon Jan 07, 2019 2:45 pm
by Jake2015
I’ve read that many times :) . Vince briefly mentions lining an engine cover on the inside and then having an upholstery shop cover the outside. I’m looking for other experiences with doing this as well as specific materials for lining.

Re: Engine cover sound and heat reduction

Posted: Tue Jan 08, 2019 2:33 pm
by Merrick
I have seen Dynamat material used to line the engine compartment but I've been looking for a chance to try this spray material- https://www.lizardskin.com/sound-contro ... ation.html

all kinds of other things looks interesting too-
https://hushmat.com/
https://www.rattlemat.com/rattle-mat/
https://www.soundproofcow.com/product/r ... -material/


or... sound damping high temperature blanket there is this- https://aquietrefuge.com/best-soundproof-blankets/

though for a top engine cover blanket, maybe some cheap moving blankets sandwiched between some welding blankets but I don't think the top of the cover would ever get hot enough to worry about that. mm

Re: Engine cover sound and heat reduction

Posted: Tue Jan 08, 2019 4:09 pm
by rmel
There's numerous companies out there that boast of superior performance
on Noise and Heat reduction.

The one thing to look for is not the Marketing hype but actual data with charts
showing the attenuation of noise and heat. If you can't find any data it either
doesn't exist or the product is crap. For noise, to look for, is decibels reduction
versus the frequency of the noise. Some will also show variance versus ambient
temperature, as these materials will perform worse at higher temperatures.
Any product that claims great noise reduction but is a thin application is a bunch
of hooey. Noise reduction requires multiple layers to have any impact and also a
lot of mass to attenuate. That's why the top of the line materials are HEAVY. In
the past Lead cladding was used for the premiere dampers.

Under the doghouse your limited due to the gap in space between the cover and
engine and the need for materials with moderately high heat tolerance.

Re: Engine cover sound and heat reduction

Posted: Tue Jan 08, 2019 10:53 pm
by rmel
Here's an example of a product from SecondskinAudio that reduces both heat and
sound and is intended for high temp applications such as Engine compartments.
https://store.secondskinaudio.com/heat- ... de-in-usa/

There are several good companies out there, I personally like Second skin due to
their great technical support, e.g. I have called and actually talked to an engineer
who was very willing to share data and provide suggestions, that's my experience anyway.

Their material, Heat Wave pro, is more than sufficient for the temps under the Dog house.
It is only 3/8" thick, that should be thin enough to not interfere. I have seen thicker material
from other companies up to 3/4" but that just is too thick to not be a problem. I have a similar
material under my Dog house, about 3/8" to 1/2" thick, but I run with EFI and have more
space under the dog house than typical -and- it's getting near time to replace it due to some
wear and tear.

This Heat Wave Pro has a high R value, and reflects radiant heat, the noise absorption is no
where near what mass loaded Vinyl can achieve, but MLV can't take the heat alone, without a
protective barrier over it. They do suggest using vibration damper under but for the Dog house
this is irrelevant as that molding won't resonate per se.

Re: Engine cover sound and heat reduction

Posted: Thu Jan 10, 2019 7:37 pm
by TechMOGogy
The entire inside of my truck is coated with Al’s heat and noise reducer (als-hnr)
Not sure it makes a ton of difference. We have it then a rubber coating over top of it on the outside of the doghouse.
https://alsliner.com/shop/heat-and-noise-reduction/
You can see it in the build thread. viewtopic.php?f=18&t=9769&start=30#p79437

Re: Engine cover sound and heat reduction

Posted: Thu Jan 10, 2019 9:30 pm
by rmel
Dan, "Al's" fails my sniff test :P -- they didn't post any data, just claims.

A thin layer of anything just ain't going to make a huge difference in either
heat or noise -- although better than nothing.

If they had data, they would be sighting a specific ASTM test result. The lack
of a test reference means they either didn't bother to test, or did and had
marginal results. IMHO no data don't buy. Testing to a standard is expensive.
Some tests are MANDATORY, some are optional. Materials in an engine
compartment, near fuel requires flame and combustion testing, they most
likely got that testing done to avoid liability -but- as a heat barrier that is not
required testing. Was it performed? Maybe, maybe not. If it was they would be
bragging about the results if they were good :?

Re: Engine cover sound and heat reduction

Posted: Sat Jan 12, 2019 9:41 am
by TechMOGogy
100% agree that a thin coating makes very little difference but I went with the “something is better than nothing” attitude.
I was not trying to suppress engine/gear noise, my thought was reduce the potential sheet metal reverbs.
Al’s parent company Scorpion Protective Coatings has test data somewhere, back when my Pinz was being restored all I did was research for every step of the process. Will see if I can find what they sent me.

Re: Engine cover sound and heat reduction

Posted: Sat Jan 12, 2019 11:49 am
by rmel
In one of my prior lives I learned the hard way "Verify then trust" rather than "Trust but verify" :wink:

Well, some thin coatings do work. For example bonded Ceramics on Exhaust components. But that
works is it's the right process that results in molecular bonding. The "paint on" products are a different story.

cheers,

Re: Engine cover sound and heat reduction

Posted: Sun Jan 13, 2019 2:25 pm
by BobbyD
I have not realized any issues regarding heat from the engine and when still/stopped not bad regarding sound. My experience was the overall sound comes from rolling and vibration of the flat body panels. Though, during the rebuild, the interior was Linex'ed including the removable engine covering. I am certain the Linex added mass to the cover and reduced the transmission of any engine noise and maybe heat.