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914World.com _ 914World Garage _ Reuse the engine compartment black noise insulating pads or are there better options?
Posted by: Tdskip Jan 31 2018, 03:50 PM
Take a newbie to school here if you would, I've got it set of pads that are in decent condition but I'm not sure if there are better options available...
Thanks!
Posted by: Mikey914 Jan 31 2018, 04:01 PM
Just finishing up a run of these -
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Posted by: Larmo63 Jan 31 2018, 04:07 PM
Most people take that out of the car. I did, but I like the sound of a 911 engine.
I'm weird like that. 
Posted by: Steve Jan 31 2018, 04:19 PM
There also known to trap water and cause rust issues. I would not glue it, so you can remove it and clean it occasionally.
Posted by: rgolia Jan 31 2018, 04:49 PM
Mark - When are those going to be available?
Posted by: dr914@autoatlanta.com Jan 31 2018, 05:01 PM
we like the sound deadening pads, they make a huge difference. The original ones deteriorated and held water so many a back wall was rusted by now. Years ago we are up with a solution, water proof dynamat die cut for a perfect fit and perfect look. It easily glues on to the back wall, and you can still use the clips, has superior sound insulation and, again, it totally waterproof!!!!!!!!
Posted by: burton73 Jan 31 2018, 05:40 PM
George,
Does it have a stickem back as my v8 car does not have clips?
Bob B
Posted by: scallyk9 Jan 31 2018, 05:42 PM
On my 3.2L conversion, the sound deadening is on the interior side of the bulkhead because of the Dzus fastened access door for the fan.
My LE has one more like the one shown in post #2 that won't hold water.
Posted by: Tdskip Jan 31 2018, 06:53 PM
Thanks for the discussion and education.
Posted by: Perry Kiehl Jan 31 2018, 09:41 PM
Get the one from Mikey!
Posted by: Mikey914 Jan 31 2018, 09:47 PM
We are using a felt like factory. It’s then treated to repel water and we bond a rubber backing to it to look like OEM. We have also backed the exposed side to make easier to glue (and use less). I had been waiting to try Velcro 1st.
I’ve had 3 people that have dropped by the shop and literally bought these before we listed them. We will do a group buy at $105 each. I’ll do up an official GB post.
Mark
Posted by: Krieger Jan 31 2018, 10:19 PM
I found another used oem "sound pad". The one that is on the inside of cabin. It is pefecly shaped for all the curbes. I trimmed it to fit the engine compartment side and used 3M spray adhesive to hold it.
Posted by: bbrock Jan 31 2018, 10:57 PM
My pad is surprisingly in good shape considering all the rust that was on the rest of the car. I was thinking about spraying the uncoated side with flex seal and reinstalling it. Haven't gotten any farther than the idea though.
Posted by: Larmo63 Jan 31 2018, 11:38 PM
Even waterproof, water can still get trapped behind them.
Posted by: Mikey914 Feb 1 2018, 12:15 AM
Very true. Velcro or another method would be best. As for the interior pad behind the back pad. Most are in pretty good shape, but they are really heavy. I will get teh weight posted up on these in the morning.
Really the best way to dry out is to remove. If it's easily done, then you can inspect for rust and reinstall as required.
Posted by: bbrock Feb 1 2018, 08:38 AM
It seems the common place for upper firewall rust is the lower outside corners. Even my old rust bucket had a pristine firewall under the sound mat except those corners. If you think about it, that's the area where water absorbed by the felt would migrate and stay wet the longest. It seems waterproofing the back of those pads would be a great first step. I like the Velcro idea because if you orient the strips vertically, you would also be creating an air gap to keep moisture from getting trapped. The alternative would be to glue and seam seal around the edges but then you wouldn't be able to periodically inspect.
Deleting the sound mat is not an option for me. Even if my car was electric, I'd still be looking for ways to make it quieter.
Posted by: Mikey914 Feb 1 2018, 12:59 PM
Yes. lowest point is the issue with most cars. My car didn't come with one, but I will add, using velcro co I can easily remove should I choose so.
Mark
Posted by: Larmo63 Feb 1 2018, 01:10 PM
My latest car came to me with solid hell holes and and worn out battery tray. We welded in new battery tray parts. The firewall behind the driver's seat had wormholes, so we removed that section and stitched in a new piece from another firewall. I've seen rust issues there enough to know that I'm skeptical of putting something back in there again.
I usually drive alone (I'm an asshole 
) in my car, so a radio isn't in it and/or conversation doesn't occur very often.
I do wonder at times what this car might be like a little quieter inside. I guess I'm just used to that singing /6 now?
Posted by: gothspeed Feb 1 2018, 01:49 PM
we like the sound deadening pads, they make a huge difference. The original ones deteriorated and held water so many a back wall was rusted by now. Years ago we are up with a solution, water proof dynamat die cut for a perfect fit and perfect look. It easily glues on to the back wall, and you can still use the clips, has superior sound insulation and, again, it totally waterproof!!!!!!!!
Even waterproof, water can still get trapped behind them.
even with water repellant on the pad, it would just 'repel' the water onto the firewall. Now if we could find water repellant paint for the firewall and hell holes? 
But as you mentioned with a -6, I would not want to insulate either!
Posted by: Mikey914 Feb 1 2018, 01:57 PM
Mine are die cut.
As far as water absorption goes - The idea is it will not hold water against the metal if it's not absorbed. The real issue becomes drainage and how much water is in the engine bay and why. With a 6 it's pretty obvious, but remember The problem is more a matter of continued exposure. I do make both rain trays. 
Posted by: gothspeed Feb 1 2018, 02:47 PM
Mine are die cut.
As far as water absorption goes - The idea is it will not hold water against the metal if it's not absorbed. The real issue becomes drainage and how much water is in the engine bay and why. With a 6 it's pretty obvious, but remember The problem is more a matter of continued exposure. I do make both rain trays.
What is the thickness and weight of your pad pictured above?
Posted by: Mikey914 Feb 1 2018, 06:23 PM
68 oz with velcro. Nominal 5/8" uncompressed. Slightly thinner than OEM.
I just did the install. Went pretty easily. I'll be posting up another dreadded GB with the insatll tonight late. I have some shipping to help out with today. Mine was naked, but I will remove for Cary to patch the holes I have, Should easily go back in. I used enoough t hold it but didn't go crazy 20" of velcro. I can also include 24" strips with this.
I think you will like
Posted by: Mikey914 Feb 2 2018, 03:41 AM
Other thread is up
http://www.914world.com/bbs2/index.php?showtopic=323628
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Posted by: Mikey914 Feb 2 2018, 03:44 AM
Crappy phone camera, I'll get better pics tomorrow. This on is ok to give you a better idea of how it looks.
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Posted by: bbrock Feb 2 2018, 08:47 AM
Question: Do you make the NLA large plastic disc fastener (Part # 914 559 377 10) that helps fasten the pad to the firewall? Those usually break when removing the pad so it would be nice to have replacements.
Posted by: dr914@autoatlanta.com Feb 2 2018, 09:02 AM
You can get them at napa, almost identical to the factory original ones. Part number is 665-3116
Question: Do you make the NLA large plastic disc fastener (Part # 914 559 377 10) that helps fasten the pad to the firewall? Those usually break when removing the pad so it would be nice to have replacements.
Posted by: bbrock Feb 2 2018, 09:36 AM
You can get them at napa, almost identical to the factory original ones. Part number is 665-3116
I knew they had an assortment of these but hadn't compared to see if any match. Thanks for the P/N!Posted by: Mikey914 Feb 2 2018, 11:22 AM
Thanks,
I'll pick up a box or two and throw these in with the new pads.
Mark
Posted by: dr914@autoatlanta.com Feb 4 2018, 03:54 PM
This Dynamat firewall insulation pad almost exactly matches the late 75 76 material and provides superior sound insulation, heat insulation and is waterproof. Die cut and easily installed with trim adhesive. We also include the factory look clips
Posted by: mb911 Feb 4 2018, 04:10 PM
I am curious if one were to put something like dyna mat in the cabin would the engine compartment insulation be required?
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