[my69gofast]

Hi everybody. Does anybody know if the cocktail shaker weights installed in convertibles are really necessary? I know I read once that their function was to "stabilize" the car but I don't really see how this would work. Besides, bolting extra weights into each corner of a car seems like a crude way to go about it.

I was thinking that if they are not really necessary I might want to yank them out for weight savings.

Any input or opinions will be appreciated.

[gldn slmbr]

I only know what I've read here. GM put them there for a reason. they are stabilizers. To reduce vibration at highway speeds in convertibles.

Sean
68 327/PG convertible

[JohnZ]

The half-frame body construction doesn't have very good torsional stiffness (compared to a full-frame car or a full-unibody car), so "F"-body convertibles had a lot of "cowl shake" (what you see when you go across railroad tracks, etc. when you watch the windshield and cowl area shake back and forth, which you don't see on a coupe), and road surface irregularities at highway speed can induce the same phenomenon under certain conditions. The "cocktail shakers" have a heavy weight inside that's free to move up and down,with a spring above and below it to hold it centered vertically, and the can is filled with oil to damp the weight's motion (Corvair convertibles had the same thing, BTW). These become vibration dampers at certain frequencies and reduce the visible "cowl shake" to what Chevrolet felt was an acceptable level (as a substitute for properly-designed convertible body structure). If your car doesn't have them any more (many were trashed because people didn't know what they were and they were heavy), don't worry about it from a functional standpoint - you'll just have more "cowl shake" without them than you'd have with them in place.

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JohnZ
'69 Z28 Fathom Green

[69er]

All right, I am an idiot. I have heard people talk about cocktail shakers for a while now. What the hell is a cocktail shaker. I NEED to know. Enlighten me please.

69er

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69 Camaro 454
71 Nova 454

If your not living on the edge then your taking up too much space

[my69gofast]

Interesting. Thanks for the info. If they were a band aid fix for the lack of torsionial rigidity in convertibles, I wonder if subframe connectors would stiffen things up to the point the cocktail shakers (or lack of) would make little or no perceptible difference. I was thinking about bolting on some subframe connectors anyway.

Does anyone know how much of a weight savings would result from removing all four?

69er-The cocktail shakers look like four cylinders bolted in each corner of the convertibles. You know the vacuum reservoir cans people use when they've got a radical cam...picture one of them bolted into each corner. As for what they're for...see answer above.

[ilbl8]

i bet sub frame conector's would help alot, so would a cross brace at the rear of the tranny, you know a piece of square tube going accross and up and over the tranny. of course the best thing also is an "X" brace too.

the "X" brace is the key in my mind. it will cause the frame, if you put in sub frame conector's that is what you get a full frame, to be very stiff and not flex as much.

most full frame convertable's had a cross brace too. this give's you a very stiff frame to make up for the fact that there is no top to tie it all together, and to stop torsionial flexing and shaking of the body.

[This message has been edited by ilbl8 (edited 03-31-2001).]

[RobR]

I think I have seen it mentioned here before that they weigh about 24 lbs each.

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Rob Rice
robr54@hotmail.com
http://members.xoom.com/robr54

[my69gofast]

Thanks for the info.
My convertible does have the "X" brace on the underside of the car across the driveshaft tunnel.
Hmmm...24lbs x 4...that's almost 100 lbs (which is roughly a tenth)...I might just have to try it...

[68ragtop]

let me know how it works out, I have a paior in the rear and have been looking for a pair for the front.
John

[DjD]

The cross brace is factory... I drove a ragtop without one and the cowl and dash looked like a bowl of jello with every bump. the overall structure was reduced by removing the roof.. I think your gonna remove 100lbs by removing the shakers you'll add some of that back with subframes and you'll still loose traction off the line and finding yourself throwing weight in the trunk just to get the car to hook... Also if you go quicker than 14.0 you need a rollbar...

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...Dennis
'69 RS Convertible w/SS trim
'96 Z28SS #1679 of 2410
"The Club"

[69er]

Thanks my69gofast, I keep hearing them being mentioned but didn't know what they were. I do now, though. When in doubt, ask TEAM CAMARO.

69er




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69 Camaro 454
71 Nova 454

If your not living on the edge then your taking up too much space

[Gary Dorion]

RobR is correct. this question has appeared many times. Do a search. Bottom line is this, they are needed. My car shakes so much that it seems like your moving when you're not. GM was tight with the $ back then. If they could have saved some money by not installing them-they would. I plan to put the shakers and the X-brace in soon.

[my69gofast]

DJD and Gary- you both mention bad shaking without the brace-I wasnt thinking about removing the brace on the underside of the car(that would compromise the stiffness of the structure),just taking out the shakers. I have been planning to install subframe connectors for some time (b4 I ever thought about removing the shakers). I guess I can picture how they might work...sort of like a pickup bed that shakes when unloaded and settles down with a load.

It's just that bolting in extra weight seems like a crude way of going about it, and a lighter car usually means a better performing one. But I know they were put there to cover up a problem, so I wouldnt even try it b4 I had subframe connectors on the car.

There has been talk about the "x" brace and a "cross brace"...are these the same thing or are they different? Thanks

[RickD]

The x brace and cross brace are the same. I'd be interested in some real world experiences without the cocktail shakers but with subframe connectors. I have welded connectors which I would think are more effective so the weight loss from removing the shakers is appealing.