Rear vents above window

[dipso]

My engine is out of the car right now and I noticed it doesn't smell like gas inside anymore. I always figured it was the fuel tank, but now I assume the fumes are coming out of my carbs and into the cabin through the vent holes.

I did a lot of research here this morning and it seems there are a lot of Pelicans wondering how to replace the foam that used to be in those vents. One way is to remove the headliner and replace it properly.
I think I figured out another way and I have pictures.

First of all the foam is there for two purposes. One purpose is to keep water out of your headliner when it is windy and raining/or your washing your car.
The other is for sound. It seems that with no foam in there a lot of engine noise and traffic noise comes in through those vents, travels up your roofline and into the cabin.
This post is for for future searchers.

First of all I measured the vent openings. They are 3/8" tall and 2" wide. There are 11.



I purchased this stuff.

It is just a weatherstrip, it is solid and doesn't allow air to pass. The original stuff allowed air to pass and the cabin to breath. I am going to take my chances on the cabin breathing.


I cut the strip into 2 1/2" lengths. The vent holes are only 2" but the extra 1/4" on each side allows them to but up against each other behind the frame. Now I doubled up the weatherstrip for each hole, because once you get the piece inside it moves upwards into the cavity. Which is closer to 3/4" I assume. i slid the first piece in and up and then the second piece underneath the first piece.



This is a picture of me slicing the adhesive backing off the strip. First of all it is white and second of all I figured if I ever need to remove them it would be better if they weren't stuck in there.



Here is what it looks like finished.




I don't think it looks to bad and I am sure it will stop the water stains on my headliner as well as the gasoline fumes and engine noise.
For those of you that want to keep the vents functional but waterproof. the other thing I looked at were those nylon/ fake steel wool scrubbing pads. They looked like they would be approximately the right size to trim and insert, and would still allow air flow.

I will see how this weatherstrip stuff works first and might change it later if I need too.
Anyways, just wanted to post a detailed way to solve this problem, since I really couldn't find one already.
It seems that lots of people are missing that foam.
The whole thing took about 45 minutes and that little pick in the third picture was very helpful for moving around the foam.

[Jerome74911S]

I hope this works for you. It's a clever idea.

Wanting to cut noise, I did a similar thing, but with a single strip of foam cut to size and applied on the outside. It is stuck there temporarily, which is good since it looks weird and doesn't work especially well. I cut the black, closed-cell foam from the edge of a yoga mat and my wife didn't even notice that a little bit was missing.

In any case, mission not accomplished. No noise reduction at all and that surprised me. I'm eager to learn how yours works so that I can copy the method if you get good results.

[dipso]

Engines back at the end of the month. I'll let you know.
The stuff is in there pretty tight, I think it will work good.

[911 tweaks]

dipso & jerome...how did this work for you both...??

[Jerome74911S]

Originally Posted by 911 tweaks

dipso & jerome...how did this work for you both...??

The external, stuck-on foam I mentioned did not work. I peeled it off and, just as with attaching it, noticed no noise difference.

Therefore, I'm interested in how the idea that dipso tried worked out.

dipso, are you out there? What happened?

[ben parrish]

I actually used a strip of red duct tape on the exterior for a year or so...really cut the noise down and not at all noticeable on my car. Wonder why the vent is there in the first place? No other modern cars have them....hmm.

[javadog]

Originally Posted by ben parrish

No other modern cars have them....hmm.

Yeah, they do. They just aren't as simple, and visible, as the ones on a 911.

JR

[E Sully]

Coupe Restoration..Rear roof vents - plastic foam strip bleeding??

[dipso]

Originally Posted by Jerome74911S

The external, stuck-on foam I mentioned did not work. I peeled it off and, just as with attaching it, noticed no noise difference.

Therefore, I'm interested in how the idea that dipso tried worked out.

dipso, are you out there? What happened?

Jerome, I sent you a message earlier from my Iphone. Don't know if you received it.
Anyways, the foam is holding up good. I was just looking at it the other day and was pleased with how it looks. My car is garaged though.

As far as noise goes, I don't know. Like I said, my engine was rebuilt at the same time and now the car is noisier. I am sure it has nothing to do with the foam, but a louder engine.

I showed my mechanic and he thought it was pretty good idea. He told me there is another area to look at as well.
He said that along that area between the rear window and the rear side window, there is a sound deadening material too. I thought about shooting some low expanding foam up in there but was a little nervous. Then I just forgot.

As far as the fuel smell in the cabin, it is completely gone. I can leave my car parked for weeks with the windows up and when I enter there is no odor.
I am serious, the fuel smell was so bad that there were times I entered the cabin and was afraid to light a cigarette because I thought it would blow up.

Wish I could tell you about sound reduction, but I don't know. Outside odor reduction is fantastic.

[Jerome74911S]

Thanks for all the detail. No, I did not get the message you sent from your iPhone.

I do know about the space between the rear window and the side window, and my plan is to address it somehow this winter. Filling with a dense closed cell foam is what I think I might do.

I have a decibel meter, so I will measure inside the car, before and after doing the above, in order to have some quantified information on noise attenuation. I will post the results if they are interesting.

[dipso]

PM me when you do, if you remember, I would like to know the results. I don't get alerts to thread postings.
Thanks.