does anyone see any reason why not welding plates to box in the frame sections in the rear behind the rear suspension as long as you can still access everything. it seems to me that I would want the added frame support to stiffen up the body and frame as well as the added impact safety. any suggestions welcome. in particular this is a station wagon and if I had my kid in the back I would not want the car to crush in very far.

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1970 Chevelle 454 Wagons haul A$$ in style! "The Chopped Suburban". to see some goto
www.EINSTYN.com (http://www.EINSTYN.com) FO_FDYFO = four-fifty four! TC#1460, VCEA#2

Not sure makes sense though, why wouldn't you? I think it might be a weight thing or the fact that it might not be necessary or maybe expensive.

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1970 chevelle
406 - TH-350 - soon to be 411's
engine (http://www.chevelles.com/showroom/engine.jpg)
Interior (http://www.chevelles.com/showroom/interior.jpg)

"I didn't get pulled over for going over the speed limit, i got pulled over for getting there faster than anyone else"

if you look at all frames back there it is just a flimsy c-channel. as for weight who cares its over the rear, as for money the frame is off and it would be no problem for me to weld up now. but I can see why the factory might have wanted to save weight and money. the only reason I could see not to,is that if the frame is made more riged it will just transfer the "crumple zone" to a different location. but where and the result of that is hard to guess. maybe instead of just absorbing the impact it will shove the driveshaft into the trany or something?

In the FWIW dept-

Awhile back, I was repairing some rust damage to a '69 Vette frame. At the time, I thought about continuously welding the frame halves together rather than the stitch welds the factory made. As luck would have it, I was working with a guy who designed racing car frames. When I told him of my plans he said something to the effect:

The frame was designed to work with the car. Making alterations to the frame without knowing how it will affect the car's performance is risky.

In my case, he advised against the continuous weld saying it would significantly stiffen the frame and reduce its reaction under cornering loads.

So I am just passing along his advice- understand what you are changing before you forge ahead...

Edit- Ooops forgot to add, stiffer is not always better. The idea of crumpling is to avoid transferring high g shock loads to the occupants. Energy is absorbed by the metal deforming rather than it not giving at all and having the occupant absorb it.

[This message has been edited by JYD71_454 (edited 01-09-2002).]

I don't think that messing with the engineer's original design without knowing what it was would be a good idea. They may have engineered the chassis to flex a little in those load areas. I doubt very much if they were concerned with safety. The cars of the sixties and early seventies didn't even have rudimentary safety devices like steel side door beams, so i doubt crumple zones were even a part of their vocabulary at the time. Have you tried boxing the rear lower control arms and installing the brace from the upper control arm to the frame. These items stiffened the chassis and were part of the factory high performance packages of the time.

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65 Danube Blue 4 door wagon, 350/330hp crate with 700R4, Factory air, Factory am/fm stereo.

yes, what i have decided to do untill convinced otherwise is: well first of all to brief you, i am putting an elcamino boxed frame under my 1970 454 wagon body. wagons came with non boxed frames like coupes. otherwize they are the same as elky. it has the third rear seat that faces backwards and loaded with all the possible options, th400 and 12 posi. as far as suspension, i have in the rear boxed arms and the stiffining bar you mention a 1-3/8 sway bar and hop stop bars, all urethane bushings. in the front, 1-3/8 sway bar (reinforced mounts) all urethane bushings, boxed front lower control arms as described it the special chevelle adition of super chevy. all urethane body mounts too. i am making and bolting on braces like chevy did on there full size wagons and later monte carlo's did also. to relive the stress area behind the front suspension. these are just bars that cross over from under the engine cross member to the frame behind the front tires. these were done to help avoide the common problem of the frames cracking behind the front suspension. in addition to that i have determined that an extra gusset from the front lower control arm's rear mounting ear to the frame would be benificial, since i have seen a few of those break. the last thing i am adding is boxing and gusseting the rear section of the frame that the rear bumper mounts to. the c-chanel will be boxed like the rest of the frame. then the entire frame is getting dipped the por15 sprayed inside and out. i have undercoating wands to reach way inside the frame. yes i know the frame will be stiffer then the factory ever thought, but being a 4 door sedan wagon with urethane mounts the body and frame will become vertualy one and the suspension and tire flex will be the absorber, not the frame/body flex.

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1970 Chevelle 454 Wagons haul A$$ in style! "The Chopped Suburban". to see some goto
www.EINSTYN.com (http://www.EINSTYN.com) FO_FDYFO = four-fifty four! TC#1460, VCEA#2

I don't know about earlier years, but I do know that on the '70 model they were interested in crumple zones. Take a look at the underhood bracing. Towards the rear of the hood (and possibly in other places), there is a circular cutout in the bracing. This cutout was put there as a crumple point for the hood. In a front end collision, the hood is designed to bend at this point.

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Randy Johnson
70 Chevelle
454
12.449@107.80
1.766 60 ft.

JimN, you are probably right that there was alot less understanding of the importance of crumpling back then. I don't dispute that. However, I am specifically addressing the comment made in the original post:

"and if I had my kid in the back I would not want the car to crush in very far"

You do not want the crush zone to infringe on the occupants to be sure. However, the idea of making it even more resistant to crushing just transfers those forces to the occupants.

Some of the provisions you see today are the result of maximizing materials and structure while minimizing weight. For instance, some of the older cars I have owned were hardly dented when hit from the side just because of the metal gage and construction overkill. To lighten the car (driven by CAFE and material cost reduction), they had to use innovative construction materials and design geometries to withstand equivalent or greater force.

My 1966 Chrysler Newport didn't need no stinkin' side door beams http://www.chevelles.com/forum/biggrin.gif However, your chances of going through the side window were pretty good because the car didn't absorb the energy as well as today's designs do.

Just my double lincolns...

Actually, Jim, the 70 Chevelle DID have side beam protection in the doors, AND it worked! Ask me how I know.

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
568,000+ miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

the slot in the hood and the posts on the cowl i believe were to prevent the hood from going through the windshield and decapatating people.

[This message has been edited by FO_FDYFO (edited 01-11-2002).]

Okay, how do you know? I thought they started putting them in in '72, but that was a long time ago for an old timer like me and I may be confused by age. The automakers were just beginning to realize that kiiling off their customers was not good business practice. And the government was beginning to get on them to improve the crash worthiness of their vehicles.

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65 Danube Blue 4 door wagon, 350/330hp crate with 700R4, Factory air, Factory am/fm stereo.

Okay, how do you know? I thought they started putting them in in '72, but that was a long time ago for an old timer like me and I may be confused by age. The automakers were just beginning to realize that kiiling off their customers was not good business practice. And the government was beginning to get on them to improve the crash worthiness of their vehicles.

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65 Danube Blue 4 door wagon, 350/330hp crate with 700R4, Factory air, Factory am/fm stereo.

<BLOCKQUOTE>quote:</font><HR>Originally posted by FO_FDYFO:
i am making and bolting on braces like chevy did on there full size wagons and later monte carlo's did also. to relive the stress area behind the front suspension. these are just bars that cross over from under the engine cross member to the frame behind the front tires. these were done to help avoide the common problem of the frames cracking behind the front suspension.

[/B]<HR></BLOCKQUOTE>

Not to get off the subject but do you have more details about this? My frame is cracked behind the drivers front wheel.



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JimN, how do I know? Check out my signature. Also, I just typed a nice long reply with specific examples of how the 70 Chevelle employs crumple zones, but I mistyped my password and when I went back to correct it, my 20 minute typing job was gone! http://www.chevelles.com/forum/mad.gif Why does that happen??

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
568,000+ miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

malibujerry, i have done the same thing. after that i learned to highlight what i had just typed and right mouse click, selected "copy"., that way if that happens you can just paste it all back in. it retains the text temperarily for you. i miss spell check. my spelling sucks. i have learned to rely on it.
jmf , it is all too common to have a frame cracked there. i have several my self. i'm not sure what years wagons did it, but i do know the 1974 caprice wagon i had did. it had the round bars with flattened ends bolted on the frame from under the engine cross member to the corner of the frame behind the front tires. also the F41 frame braces for GM Midsize 78-87 elky, grand national, cutlass and grand prix. These are HEAVY DUTY F41 frame reinforcement braces which were installed on ALL of the above vehicles when the F41 "special handling" suspension package was ordered, or when that package (F41) came as a "standard feature" on models like Monte Carlo SS, Grand National, and other sport versions of 1978-88 GM "G" body vehicles. These REALLY stiffen the from frame area of you vehicle especially if you've installed the super thick f41 front swaybar. These braces "triangulate" the front frame area for added strength to prevent "flexing" while cornering and handling. i dont think these braces will fit chevelle aplications but the concept is there an the factory felt it was an improvment. so i am just doing here what i view as an improvment the my chevelle wagon should be upgraded too.


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1970 Chevelle 454 Wagons haul A$$ in style! "The Chopped Suburban". to see some goto
www.EINSTYN.com (http://www.EINSTYN.com) FO_FDYFO = four-fifty four! TC#1460, VCEA#2

I'm just a teen, but here's my opinion. Cars have become more technologically advanced in 30 years, the Chevelle's frame will make it stiffer than ANY unibody car, so if you have a daily driver and/or u live in a city with a bunch of teens who can't drive, leave perfection alone http://www.chevelles.com/forum/smile.gif. If it's 4 drag racing, go ahead. If your frame is like mine & has holes rusted in it(or cracks), weld something in those holes. If the frame breaks in a Chevelle, you are screwed.