Door sound proofing / deadening

[Bmachine]

I am in the middle of restoring my front door window regulator and entering the rabbit hole of "while I'm here". Part of that is doing everything possible to reduce the various noises the door makes either when closing or even when driving.

First Chris mentioned that there are 3 grommets that keep the door latch rods from banging around inside the door.

Then there is the obvious grey or beige plastic cover that over the door latch on the outer end of the door.

Finally, in this older thread https://e9coupe.com/forum/threads/not-a-restoration-3.7847/ Stevehose brings up that there is a plastic sleeve that is supposed to goes over the rod going to the inside door latch handle.

After doing some knocking around to see what else was vibrating, I noticed that the inside door skin has several areas that are thin and vibrating. See pic. Many people put some sound proofing on the outer door skin but I am thinking of placing a few pieces of Dynamat behind the areas outlined below. Behind, so their thickness would not get in the way of the door card. I know that several prefer the spray on stuff to eliminate the possibility of dynamat falling off but these will be smaller pieces and I am doing a thorough prep with acetone so it should last a good while. These would obviously be placed in areas where they would not impede with anything. Has anyone else done anything to that inside door skin?

 

[HB Chris]

You can fold a piece of felt over that rod and glue it or just bend it away from channel.

 

[JayWltrs]

I am in the middle of restoring my front door window regulator and entering the rabbit hole of "while I'm here". Part of that is doing everything possible to reduce the various noises the door makes either when closing or even when driving.

First Chris mentioned that there are 3 grommets that keep the door latch rods from banging around inside the door.

Then there is the obvious grey or beige plastic cover that over the door latch on the outer end of the door.

Finally, in this older thread https://e9coupe.com/forum/threads/not-a-restoration-3.7847/ Stevehose brings up that there is a plastic sleeve that is supposed to goes over the rod going to the inside door latch handle.

After doing some knocking around to see what else was vibrating, I noticed that the inside door skin has several areas that are thin and vibrating. See pic. Many people put some sound proofing on the outer door skin but I am thinking of placing a few pieces of Dynamat behind the areas outlined below. Behind, so their thickness would not get in the way of the door card. I know that several prefer the spray on stuff to eliminate the possibility of dynamat falling off but these will be smaller pieces and I am doing a thorough prep with acetone so it should last a good while. These would obviously be placed in areas where they would not impede with anything. Has anyone else done anything to that inside door skin?

Ooh! I’ve been battling the same concern and never thought of this—curious what you discover. Maybe there’s a way to rough test it short of removing all the Dynamat adhesive backing and re-assembling the entire window and door mechanism. The original square of sound mat on my outer door skin has hardened and I’m not sure how much it’s doing. But it’s hermetically sealed—not a loose bit anywhere to gain purchase. It would likely require more heat or friction to get it off than I’m not comfortable w in that location given paint age, etc. I’ve just been toying with cutting out a Dynamat “frame”for the old piece, but your idea is also intriguing.

Edit: There was a foam pad on the protruding flat portion of the regulator when I removed it originally. I think that will fall in the area of the front circle in your picture? While it was a thin sponge-like material I removed, that is the point at which it rests against the frame, and you'd need to make sure Dynamat leaves enough room--I forgot to put anything there when I re-installed it, which is one of the issues causing me to go back in:

 

[Bmachine]

Wow. Is that a brand new regulator? Nice!
Notice that it is missing the adjustable “bumpers” for the moving stopper post. This could damage the nylon on that stopper post.
Good point on the foam bit. The dynamat is not too thick so I hope it is not a problem. We will see.

 

[JayWltrs]

The bumpers stumped me for a while.
None were on when I removed them, and other folks said they weren't used on the late 74 front regulators. I actually bought some beforehand, but for the life of me can't figure out how they would fit. I'll go back and look again to make sure.

Not new--just lots of cleaning, scraping, and a little primer.

 

[HB Chris]

The stoppers are just metal bits that are adjustable on the later motors as I recall.

 

[Bmachine]

Here is what they look like. I would call them pretty indispensable myself. Otherwise you have no way of adjusting the high and low of the window. And I would think the nylon bushing would get destroyed pretty quickly.

 

[JayWltrs]

Here is what they look like. I would call them pretty indispensable myself. Otherwise you have no way of adjusting the high and low of the window. And I would think the nylon bushing would get destroyed pretty quickly.

Thanks. I have those. I was confused for a long time because I thought I was supposed to have the rubber bump stop. I'm a little slow on the uptake sometimes!

 

[HB Chris]

Here is what they look like. I would call them pretty indispensable myself. Otherwise you have no way of adjusting the high and low of the window. And I would think the nylon bushing would get destroyed pretty quickly.

That’s it

 

[Bmachine]

Ok. I Went ahead and added some Dynamat to the left and to the right of the existing factory sound deadening material on the outer skin and also 4 pieces behind the inside door skin in the positions illustrated above.

There is definitely an improvement. I wouldn’t call it night and day but you can certainly hear it being more “dead”. I made a little comparison video. First, drivers door with Dynamat and then passenger side without.

 

[JayWltrs]

Ok. I Went ahead and added some Dynamat to the left and to the right of the existing factory sound deadening material on the outer skin and also 4 pieces behind the inside door skin in the positions illustrated above.

There is definitely an improvement. I wouldn’t call it night and day but you can certainly hear it being more “dead”. I made a little comparison video. First, drivers door with Dynamat and then passenger side without.

I’m convinced. When I removed the layers of evil petrified adhesive on those panels, it worsened the tinny sound. This should help.

 

[Gazz]

Damn, I thought I had finished dynamatting. I didn't think of the inner door skin.
My car was sandblasted which removed the old matting entirely so I have dynamatted everywhere including the inside of the outer door skin. Made a huge difference. Doors close with a thunk instead of a clang.

 

[eriknetherlands]

I choose to like the clang it makes when I shut it, it saves me a lotta work... But I also think the Dynamat definetly makes a difference in your driver's door.

 

[Bmachine]

It’s one of the many small steps that, in combination with the others mentioned in post #1, help make this part of the car feel more solid.

It’s really fairly simple but, at the risk of stating the obvious, here are some observations:

1, it has to be done with the regulator out for best access
2, you really want to thoroughly clean wherever you’re going to apply it so it doesn’t fall off after a couple of years. I used acetone.
3, cut a template out of paper or cardboard to the exact shape you will need and test thoroughly before cutting the Dynamat. (IMPORTANT: remember to transfer the template shape to the sticky side of the Dynamat since you will be applying it towards you instead of the usual away from you. )
4, only peel the backing paper a couple of finger width at the top of the piece and carefully slide it in position. Since you can’t see what you’re doing it all has to be done by feel. Make sure the whole piece is exactly where you want it before you press that leading edge down. Once it sticks somewhere it is nearly impossible to move it. Then slowly pull the rest of the paper one inch at a time and press it around the bends of the sheet metal.

 

[Gazz]

Use masking tape as guide points for positioning sheets.