chassis stiffening a painted car

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dusterbd13

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so, in the process of converting my duster from a resto/street/strip car to a pro-touring car, ive come into some interesting problems.

car had subframe connectors installed years ago, and then some very good, and very expensive, pain and body work done.

now there's all sorts of further chassis stiffening products out there, and I know lots more about things. the opportunity to stitch weld the car is long past, so that's off the table. welding the k-frame is on the short list, and the LCA are already boxed. t-bar cross member was welded to the floor pan when I cut it in half for the five speed swap.

Id like to do the radiator support, front fender braces, torque boxes, maybe a monte carlo bar, maybe an x-brace between the subframe connectors.

I know I can do a monte carlo bar, and the x-brace without disturbing paint and body. but what about the rest? maybe the torque boxes, as I don't think they weld to the pinch weld at the lower body.

the core support brace: does it need welded where it would burn the paint past the flange on the frame rails? I can paint the frame rails black to hide it that far, but the horizontal surfaces and inner fenders are very nice and I don't want to hurt them. core support is blacked out behind the grill, so no concerns there.

I believe the inner fender braces are out completely, but I'm not sure.

so, what all can I do without hurting paint or needing to go back to bodyshop hell?
 
75slant6 said:
Nobody?
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I'd really want to consider what you are trying to accomplish. Are you running into problems or just want to catch up with the jones'es? Sounds like it's already a really nice ride, paint wise anyway. Lay it out for us and throw some pic's for flavor
 
Blind Squirrel said:
I'd really want to consider what you are trying to accomplish. Are you running into problems or just want to catch up with the jones'es? Sounds like it's already a really nice ride, paint wise anyway. Lay it out for us and throw some pic's for flavor
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This ^
 
And if you're worried about welding. Check out some of the new bonding products that are available now days. I hear tell some are stronger than welds. How could it hurt to maybe bond in an edge next to paint and weld in the rest. Break out those kindergarten skills, glue up some panels and go autocrossing. Be the test mule, do a build thread and become the hero.:thumbsup:
 
for some reason the board never notified me of replies.

yes, there is noticeable chassis flex. you can watch door gaps change over railroad tracks, driveway entrances, etc. I also want to further reinforce the torsion bar cross member where I chopped the crap out of it for the tremec.

and thanks for linking the build thread. I should have done that earlier.

also, I had forgotten about panel bond. I've seen my buddy bill do some testing with his frame straightener and tow truck he has never broken a properly bonded panel. torn metal, etc, but never broken the glue. that is absolute genius for this application. THANK YOU!!!
 
Yup. Not nearly as bad as before, but it still does. Now, this thing has been on a frame rack twice due to being totalled twice, so that may have some bearing on it. It's also more torsional twist that longitudinal.
 
The torque boxes weld to the back of the rocker pinch weld. You're not going to install those without disturbing the paint on the outside of the pinch weld. And none of the torque boxes you can buy have a flange that you could use panel bond on, they just butt weld to the back of the rockers. This picture doesn't show much of the rocker, but if you look where the fender bolts on you can see the paint has burned and changed colors because of the welding behind it. Same deal with the rear torque boxes, and no fender dog leg to cover the rocker there.

IMG_5009_zps080dc28f.jpg


The radiator support brace depends on what kind you do. A tubular brace should land just on the frame rails, although you'll need to modify the bottom of the radiator support shroud. That's pretty much blacked out on most cars, but I'm not sure about yours. The US Cartool brace welds to the current radiator support, so, you'd need to repaint the entire lower part of the radiator support brace. If the whole thing is blacked out, great. If not, well, good luck.
 
did some ustool boxes , still needed to repaint on the rear of the rockers , did the front rad support brace as well added a small right angle to the front openning , plug and stitch welded . made it stronger , as the stock tin type .

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I did weld in subframe connectors, torque boxes and the rad core support on a painted car without much trouble. I have the inner fender braces but I know I will damage the paint with those, yikes.

20160320_165638.jpg


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pomonamissel said:
did some ustool boxes , still needed to repaint on the rear of the rockers , did the front rad support brace as well added a small right angle to the front openning , plug and stitch welded . made it stronger , as the stock tin type .

View attachment 1714930008

View attachment 1714930009
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bentdart47 said:
I did weld in subframe connectors, torque boxes and the rad core support on a painted car without much trouble. I have the inner fender braces but I know I will damage the paint with those, yikes.

View attachment 1714930061

View attachment 1714930062
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Was the front radiator support plate a replacement front radiator core support or a piece of sheet metal you weld over the current one?
 
Put a cage in it, no amount of sheet metal welding or body bracing makes a car feel a solid as a cage will.
 
I welded in the US Car Tool lower rad support and will have to repaint most of that area, but was to be expected. Mines blacked out so it will be pretty easy to finish up without anyone noticing.
20160322_122656.jpg


Edit: I need to figure out how to upload photos on the new site!
 
67autocross said:
Put a cage in it, no amount of sheet metal welding or body bracing makes a car feel a solid as a cage will.
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Cages are a pain in the butt for anything other than a race car. And they're overkill for anything other than a race car. These cars are made entirely out of sheet metal to begin with, and you can do a lot with by adding some simple bracing. No, it won't make it as rigid as a cage, but it doesn't need to either.
 
MuuMuu101 said:
Was the front radiator support plate a replacement front radiator core support or a piece of sheet metal you weld over the current one?
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You can go either way with the US car tool piece. I opted to remove my old core support because it was beat up. I made some mods to the US car tool piece as well for additional rigidity.

20160323_165106.jpg


20160325_182653.jpg
 
bentdart47 said:
You can go either way with the US car tool piece. I opted to remove my old core support because it was beat up. I made some mods to the US car tool piece as well for additional rigidity.
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Hey now that's a good idea! :thumbsup:

Yeah I'd seen the US Cartool pieces welded over the stock radiator support brace, but hadn't seen them welding in place of it before. I know the US Cartool piece is thicker than stock anyway so it's an improvement either way. And that stiffening tube you added will make a BIG difference. Nice work!
 
Not anymore. Dillinger Chassis used to make one like that, but he's long gone.
 
If you want to add more support across the front without messing with the paint put a second rad support the behind the rad, make it out of round tubing with some tight 90 degree bends on each end.
I would not personally not bet big money that these rad braces really do much but they can't hurt either.
 
67autocross said:
If you want to add more support across the front without messing with the paint put a second rad support the behind the rad, make it out of round tubing with some tight 90 degree bends on each end.
I would not personally not bet big money that these rad braces really do much but they can't hurt either.
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I have a tube welded to the front frame rails just behind the radiator and in front of the sway bar. It attaches to the frame with a pair of 2 inch long square boxes welded to the underside of the frame rails. It's clean, strong and ties the front frame longitudinals together nicely. I also welded my shock towers solidly to the inner fender wells when I installed the shock tower to firewall braces. My original spot welds had cracked and ripped over the years do to the flimsy factory attachment method. I made a nice Monte Carlo bar that bolts on with out too much modification using the fender attaching bolts and to the pinch weld above the wiper motor.
 
jbc426 said:
I have a tube welded to the front frame rails just behind the radiator and in front of the sway bar. It attaches to the frame with a pair of 2 inch long square boxes welded to the underside of the frame rails. It's clean, strong and ties the front frame longitudinals together nicely. I also welded my shock towers solidly to the inner fender wells when I installed the shock tower to firewall braces. My original spot welds had cracked and ripped over the years do to the flimsy factory attachment method. I made a nice Monte Carlo bar that bolts on with out too much modification using the fender attaching bolts and to the pinch weld above the wiper motor.
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Do you have pictures of these mods? Sounds like what I am thinking of doing.
 
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