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-   -   Vibrating Bulkhead (Rear) Panel (http://www.clubcobra.com/forums/kirkham-motorsports/92686-vibrating-bulkhead-rear-panel.html)

RodKnock 10-29-2008 05:20 PM

Vibrating Bulkhead (Rear) Panel
 
Now after driving almost 500 miles on my car, I've noticed that the panel behind the seats in my Kirkham vibrates, but only at idle, since I assume that's when the car shakes the most. Have others experienced the same problem and, if so, how have they fixed it? Silicone sealer? Carpet? More rivets? There are plenty of rivets and they all seem to be tight.

When pressed upon by hand, at idle, the vibration disappears. Thank you in advance for any suggestions.

4pipes 10-29-2008 05:34 PM

Glue a hand on it :)

Sorry Rodney, I couldn't resist.

Maurice Johnson 10-29-2008 08:06 PM

Thats not vibration--it's stored energy. It wants to MOVE, man:) Like holding back a Pit Bull

Got the Bug 10-29-2008 08:19 PM

1. Your sidepipes aren't loud enough
2. You shouldn't be at idle long enough for the vibration to bother you
3. This isn't your Lexus (insert daily driver here________).

:LOL::LOL::LOL:

Ronbo 10-29-2008 08:20 PM

Stuff some cardboard in between that upper bar and the panel (though the trunk). If thats it, glue a piece of rubber weaterstrip in there.

Check that upper roll bar clamp as well.

RodKnock 10-29-2008 09:12 PM

Everybody wants to be a comedian.

Dave, I thought about keeping my hand on the panel, but then I actually needed to steer the car and shift too. :eek:

Doug, that darn commute traffic in the morning at the 280/880 junction. Why down there you say? If you can believe it, I had to redo my CHP trip. Please don't ask (back to BAR tomorrow...again):CRY:

Sidepipes are too quiet, you're right. I might need to step up to some really loud ones.

However, I really loved the old lady driving her Mercedes next to me, in stop and go traffic, who had all her windows up and was still waving her hand in front of her face because of the alleged gas fumes (gotta love Sunoco 110) :)

I thought maybe some other owners had the same problem.

Thanks, Ron.

Igofastr 10-29-2008 11:01 PM

I haven't had that problem, and I've got 5500+miles on mine. I suspect that you just have some odd harmonics going on. Could be a loose panel, but I doubt it. Have you tried altering the RPM at idle? Does it get better? As a last resort, after checking to make sure it isn't actually loose, you might want to try sticking some of those "sound deadening" sheets to the panel (I'd do it from the trunk side)...can't think of the trade name at the moment, but it may alter the frequency of the panel enough to prevent the vibration.

Good luck.

big-boss 10-29-2008 11:25 PM

Yes , I have the same problem. When I start going it goes right away-does yours? I will probably not do anything with mine - it is not worth me taking the rear bulkhead out to fix. If I did I would put some kind of warp in it that you wouldn't notice. The drag race guys run all their pannels in one of those bead making things. My issue is simple "oil canning" The guys with carpet probably do not have the problem but then their cars are alot heavier and slower.

GUNNAR 10-29-2008 11:54 PM

RodKnock,

I'm glad that you asked the question, because I have the exact same thing with my 289 FIA. I would also appreciate suggestions.

FatBoy 10-30-2008 02:51 AM

I had exactly the same problem in mine. In my case it wasn't the rear bulkhead though that was vibrating, it was the trunk floor directly behind it i.e. the top if the step at the reaf of the trunk.
Have a look at the rivets that hold it down, mine weren't pulled down tight and allowed the panel to buzz. I suspect, although I couldn't be certain, that there is a slight process error in the assembly. It would appear that the trunk floor is put in after the rear bulkhead, which means the rivet gun can't get in properly to pull the rivets down when the floor is put in due to the bulkhead getting in the way.
As a temporary measure, I unscrewed the small panel in the trunk that gives access to the diff and put some thin foam between the top panel and the chassis crossmember that supports it. This gave enough tension to stop the vibrating.
Over the winter, I intend to take out the rear bulkhead and rivet the trunk floor down properly.
I hope that helps.

Paul

Jerry Clayton 10-30-2008 08:16 AM

I heard the Migs had the same proublem---especially with 50 cal slugs going thru them

Murphy 10-30-2008 08:37 AM

I had the same problem
 
I found the rectangular panel at the forward part of the trunk interior to vibrate. It has screws attaching it and is easily removed from inside the trunk. I am guessing on the size but it is about 5" x 15". I took mine off and put a very thin foam tape as a gasket on the contact surface and eliminated the noise.

RodKnock 10-30-2008 04:39 PM

Great suggestions, thank you.

In the big scheme of things, it's really no big deal, but I would like to eliminate any vibrations, rattles, and buzzing, if I can. Mine does it at idle only and it does it frequently, but not 100% of the time. Once the car is moving the vibration stops.

I need some "winter" projects, and this one seems right up my alley. I very much appreciate the help. Thanks again.

xlr8or 10-30-2008 04:49 PM

Rodney if you look at the 1" cross bar that the rollbar support bolts go through you will be able to get some cardboard as mentioned between that and the panel.
Other option is to add rivets from the bulkhead side or dynamat type sound deadener in the trunk side.
Third option is that it's actually the trunk floor just behind the bulkhead. That rattled on mine as well. I took the diff access panel off from the trunk and put a 12X12 sheet of dynamat on the bottom of it. Cleared it right up.

392cobra 10-30-2008 04:56 PM

Is it possible that this option was installed in the wrong place ?

http://viberider.com/vibe_rider.asp


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