Under hood insulation

Discussion in 'Camaro Questions' started by Millwright, Jun 7, 2019.

  1. Millwright

    Millwright Member

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    The previous owner of my car installed a thick insulation blanket to the bottom of the hood. What is this doing for me and should I leave it there? It seems many other cars do not have this. I am thinking it would look much nicer without it.
     
  2. CDesperado

    CDesperado Veteran Member Lifetime Gold Member

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    That is a heat barrier and sound insulator... IIRC, it was optional on most cars. Most people choose to remove them because they end up getting very dirty and look nasty. You'll notice more heat on the hood if you remove it and in theory, it protects the paint... but Im not sure how much sound deadening they actually can do. I doubt you would notice.
     
  3. BillyDean7173

    BillyDean7173 Veteran Member

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    I thought the idea for hood insulation was a reduction in heat on your hood paint and noise. Also, the hood insulation clips were supposed to melt in case of a fire and the insulation, in theory, would help smother the fire. I've always wondered if they absorb moisture and possibly cause damage to the air cleaner lid.

    Also, as a member pointed out this week in another thread about roof insulation.
    http://www.nastyz28.com/camaro/camaro73.html
    1973 Z54 Interior Decor/Quiet Sound - Includes glove compartment light and additional instrument cluster lighting; woodgrain accents on instrument cluster; special engine compartment, hood and interior insulation. (Standard with Type LT)

    I bought a molded piece from Camaro Central back when it was on sale and had a discount on shipping. It's a really nice piece and I plan on using it along with either my American Autowire or NOS hood light.
     
  4. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    Pretty sure it was for noise. Most of the optional Deluxe interior packages had it. Interesting the Z28 package usually had it too, at least in 1970. I've heard hearsay that it can reduce the cracking of the OEM lacquer paint over time. Nothing definitive.

    Keep in mind that it is fiberglas which is abrasive. It can cause scratches to the air cleaner top and wear the paint on the radiator top panel. Some folks throw a towel over the air cleaner before closing the hood.
     
  5. CDesperado

    CDesperado Veteran Member Lifetime Gold Member

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    I have the piece, but havent installed it on my car yet. I may, because I am doing everything I can to quiet down the cabin.

    I have seen car detailers remove the insulation from the car to wash it with a power washer or garden hose, then clean the under side of the hood, then put the insulation back on the car.
     
  6. xten

    xten Veteran Member

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    I know it helps with noise. We were taking a hood off and my right ear was on the insulation. I thought for a split second I was losing my hearing in that ear. Couldn't even hear the radio out of that one.
     
  7. CDesperado

    CDesperado Veteran Member Lifetime Gold Member

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    Good - that makes me feel better. I have a db meter and am going to do some A/B test this weekend - first with a measurement from inside the cabin without the insulator, and then a second measurement with the insulator. It should be interesting to see how much of a difference it really makes bc it seems like most of the sound is coming thru my firewall, which has a layer of SecondSkin and a second piece of firewall insulation already. I am planning to add a layer of closed cell foam, mass loaded vinyl, and a heat shield within the next week or so, all in an attempt to quiet down the cabin.
     
  8. badazz81z28

    badazz81z28 Veteran Member

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    I ended up installing hood insulation on mine. It does quite the car down a little on the outside. I recently installed a lot of sound deadener on the inside, so the dramatic reduction of noise on the inside is hard to quantify. I have noticed the engine heats up quicker too. I think it causes more heat to be trapped in the engine bay.
     
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  9. CDesperado

    CDesperado Veteran Member Lifetime Gold Member

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    Not to thread-jack, but I am curious what you used. I have a layer of SecondSkin covering the floorpan and a 1/2" of jute (also 100% coverage). I am adding the Foam and MLV and probably an additional layer of thermal barrier.
     
  10. xten

    xten Veteran Member

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    Curious to see the difference if any inside. You definitely hear less engine noise outside the vehicle.
     

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