Steering, Suspension, & Brakes

tips, technology, tools and techniques related to non-driveline mechanical components

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Richard Carr
Louisa VA
(10 posts)

11/26/2008 12:17PM

Main British Car:
1980 MG B Buick 215

Body Stiffening Issue
Posted by: pawp
Date: February 01, 2010 04:39PM

I suppose this could go in the body or handling sections.

I am considering removing the bulkhead between the trunk and passenger area on my 1980 convertible project. This will facilitate a pass through compartment arrangement for luggage etc. My plan is to surround the cutout with 1" square tubing 1/8" wall around the opening. It will tie into the lower inner fender well on the sides, continue vertically up to the top of the panel just under the sheet metal where it will join a horizontal piece be tied into the upper wheel well area on each sides. The rectangle structure will also tie to the left over sheet metal and provide a frame for the passage door. Do you think this arrangement will strengthen or weaken the existing structure?

Bill Young
Bill Young
Kansas City, MO
(1337 posts)

10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

authors avatar
Re: Body Stiffening Issue
Posted by: Bill Young
Date: February 01, 2010 04:47PM

I doubt if you'd notice any difference in structure, especially with the addition of the tubing section you describe. That bulkhead does offer some torsional stiffness, but not much since the upper portion of the body isn't tied to the front of the car at all. The GTs had nothing there at all and the roof didn't have any sort of diagonal brace to prevent torisonal twist.

Todd Kishbach

(386 posts)

12/04/2009 07:42AM

Main British Car:

Re: Body Stiffening Issue
Posted by: tr8todd
Date: February 01, 2010 07:59PM

My B had that panel cut out before I bought the car, and no other metal was there to replace it. I put a welded in roll hoop and seem welded the floors and rockers during the sheet metal resto. It is very stiff now, so I can't imagine that panel is more than a crush panel for side impacts. You can see right thru to the trunk in this photo. This car was originally a showroom stock race car in the 70s. You can still see where the bolt in cage feet were mounted next to the battery boxes. The bolt holes are still there.

Steve Kimball
Southwest NM
(30 posts)

03/02/2008 10:58AM

Main British Car:
67 Sunbeam, 2.8 L V6 Ford,

Re: Body Stiffening Issue
Posted by: eyeosteverino
Date: February 15, 2010 11:04PM

I agree with B.Y. Might be easier to to just roll the edges. My Midget was built with a pass thru and it's handy.

Art Gertz
Winchester, CA.
(3166 posts)

04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Body Stiffening Issue/ deflection test ?
Posted by: roverman
Date: March 15, 2010 07:26PM

Anybody ? Post on measuring torsional strength, in real world ? We have some "brainy types", how bout ? Thanks, roverman.

Larry Shimp

(223 posts)

11/17/2007 01:13PM

Main British Car:
1968 MGB GT Ford 302 crate engine

authors avatar
Re: Body Stiffening Issue
Posted by: 302GT
Date: July 28, 2010 09:03AM

There is an extensive discussion on measuring torsional body rigidity in a Mustang forum that might supply some ideas. The link is:

Fred Key
West coast - Canada
(1318 posts)

05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: Body Stiffening Issue
Posted by: DiDueColpi
Date: July 28, 2010 03:02PM

Hey Richard;
Just my two bits worth, but I believe that bulkhead was a north american requirement to separate the fuel tank area from the passenger compartment. It really doesn't do much for rigidity. However I think anything that you can do to improve torsional stiffness and side impact protection is a good thing. So I would brace it up and add at least a 3 point roll bar.
On my race cars we have a cheap and easy way of gaging improvements to the body strength.
We set the car up on jack stands at the four extreme corners, weigh down the passenger compartment ( bags of sand work well) and level the chassis. I use an old laser level that has magnets glued to the bottom and a target made from some leftover lexan and magnets. Sight the laser and target over the area to be checked, such as L front fender to R rear fender. Then just jack up each corner an inch or two and record the deflection on your target. You will be surprised at the amount of movement.
The measurements won't really mean anything but they will give you a way to judge any improvements.

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