quick subframe connectors question

[diymirage]

hey guys
i am getting ready to build some subframe connectors for the duster

i think i got a pretty good plan (looked at the BBdart page, and i got a copy of the plans one of our members made, but i got just one (or two) quick questions

the big one is the fuel line
i will be using 2x3 box steel, and it looks like if i tuck it over the rear frame rails i will come in pretty close to where the fuel line runs throuh the front sub frame

how close can i safely get to the fuel line while welding?

or is there a good way to shield the fuel line from the heat and sparks while welding?

and secondly, the plans i have call for "plug welds"
is that just for added strength?
it is simply a hole i weld in, correct?

 

[dano]

Unless your sparks are molten lava it should be fine. Wrap a piece of leather (preferred) or a wet cloth around it if you want. The plug weld helps support the end plates in middle. Disconnect your battery when you weld the body. Make sure there are no fuel, oil or brake fluid leaks or damp areas. Is your carpet in?

 

[diymirage]

thanks for the reply

yes, I have carpet and full interior in

 

[mopowers]

They are the best bang for your buck improvement people can do to the old Mopars. Have you considered taking the seats and carpet out and tying them into the floor? Not a lot of work for a lot more support IMO.

If you need to, it's not too tough to snap the fuel lines out of their clips and move them if you need to. Otherwise, just be careful.

 

[TrailBeast]

When I did mine I drilled 2 - 1/2in holes only in the sides of the connectors so where it slid over the rear subframe I could weld in the holes to the subframe.
(Plug welds)
I always intended to go back and taper the ends down and weld that to the subframe but never did.
The red line shows where they are welded up closed to the outside elements, so dirt or moisture doesn't get inside the tubes.

 

[JoePole1]

I welded in my 2x3 box steel frame connectors with my interior in. No issues. Mine connect the front subframe by the torsion bar mounts to the rear subame
by the front leaf spring mount and they do not contact the floor. This is a 72 B-body but I believe there is no difference with an A-body. I used a piece of scrap to protect any fuel/brake lines. Made a huge difference in handling.

 

[ir3333]

are you dealing with a lot of torque and slicks that will hook?

 

[diymirage]

are you dealing with a lot of torque and slicks that will hook?

meh, not really
its a 408 LA i dont remember the exact numbers, around 450 pounds of torque

once the gulag open up commerce again i will swap out the N50s for a set of nitto 555s, so i should do allright then

 

[diymirage]

When I did mine I drilled 2 - 1/2in holes only in the sides of the connectors so where it slid over the rear subframe I could weld in the holes to the subframe.
(Plug welds)
I always intended to go back and taper the ends down and weld that to the subframe but never did.
The red line shows where they are welded up closed to the outside elements, so dirt or moisture doesn't get inside the tubes.

View attachment 1715513417

that is exactly what i intend to do
the plans i found show a little piece folded over and welded in, right where your red line is

i just didnt really want to drill the plug weld holes since i only have a battery powered drill, and the steel is 1/8 inch thick

(im still not even sure it will fit over the rear frame rails as thick as the walls are, but we will see)

 

[TrailBeast]

that is exactly what i intend to do
the plans i found show a little piece folded over and welded in, right where your red line is

i just didnt really want to drill the plug weld holes since i only have a battery powered drill, and the steel is 1/8 inch thick

(im still not even sure it will fit over the rear frame rails as thick as the walls are, but we will see)

Yea, those were probably my plans that I posted awhile back.
Drill 4 1/4 holes them if you don't want to drill 1/2.
It would probably be stronger than pinch welds.
My material is 2x3 .085 wall and it needed to be convinced but went over the subframe sections nice and tight.

 

[Bad Sport]

FWIW, make sure the car is level and you check your doors for opening and closing before welding everything.

You will be amazed at the difference in feel of the car.

 

[diymirage]

Yea, those were probably my plans that I posted awhile back.
Drill 4 1/4 holes them if you don't want to drill 1/2.
It would probably be stronger than pinch welds.
My material is 2x3 .085 wall and it needed to be convinced but went over the subframe sections nice and tight.

sounds like it, the plans call for .085 walls
would be nice if whoever ordered the steel would have mentioned that

on the bright side, maybe this will be so tight on the subframe i wont even need to weld it

 

[mopowers]

You could always slice the corners of the tubing at that end if it's too tight or too loose and weld it up so it's perfect.

 

[TrailBeast]

meh, not really
its a 408 LA i dont remember the exact numbers, around 450 pounds of torque

once the gulag open up commerce again i will swap out the N50s for a set of nitto 555s, so i should do allright then

You might take a look at the Nitto Neo Gen series.
https://www.amazon.com/dp/B004QL6PXK/?tag=fabo03-20

They have more rubber on the outer edges of the tread where a lot of the load goes in corners.
The ONE thing I don't really like about them is they are too sticky for me.
They are amazing in the rain though.

 

[DrCharles]

How are they too sticky? Isn't grip the name of the game... or do you just prefer the noise and smoke show over 60' times? ;)

 

[mopar74]

diymirage,
I built and installed the same subframe connectors following the plans by trailbeast for a 69 valiant I had. If I recall I used .125 2x3 tube also. it was tight going on the rear but nothing a small bottle jack couldn't handle. I built four boxes to set the car on so the chassis was loaded and it aloud plenty of room to move freely under the car without jack stands being in the way.

 

[DrCharles]

I made mine out of 1/8" wall too. But I'm not a good enough welder to feel confident in welding them myself. Especially underneath the car, even if up on boxes.

Would it work if I make a couple of plug welds on each end, then carefully drive the car to a shop with a four-post lift (or wheel supports like yours), and have them fully welded in?

 

[diymirage]

I made mine out of 1/8" wall too. But I'm not a good enough welder to feel confident in welding them myself. Especially underneath the car, even if up on boxes.

Would it work if I make a couple of plug welds on each end, then carefully drive the car to a shop with a four-post lift (or wheel supports like yours), and have them fully welded in?

how are you gonna plug weld the front?
add plates to it?

did you make yours yet?
ill prolly get chopping on mine tomorrow, and im excited to find if the 1/8th wall clears the rails

im pretty confident in my welds
they may not look pretty but they will hold up just fine

 

[TrailBeast]

How are they too sticky? Isn't grip the name of the game... or do you just prefer the noise and smoke show over 60' times? ;)

I guess you could say/ask that.
I don't race the car, and it's my daily driver.
Want to be able to play without risking shooting off into a ditch because the tires grabbed so hard.

 

[TrailBeast]

how are you gonna plug weld the front?
add plates to it?

did you make yours yet?
ill prolly get chopping on mine tomorrow, and im excited to find if the 1/8th wall clears the rails

im pretty confident in my welds
they may not look pretty but they will hold up just fine

You are going to love your car all over again when you feel the difference.

 

[JoePole1]

I used the sub connectors from mancini but you can make these easily from 1.5x2 inch or whatever stock you want. The front has a steel plate tht T's and the rear has pieces that extend on both sides. They were a little too narrow so I cut them to straddle the rear frame and then rewelded. There is plenty of plate on the sides for lots of welds. Has held up fine for 10 years even with my crappy welding skills at the time. I did have to flatten the pinch weld on the floor to get the connectors up as high as possible.
Note that this is a street only car and also a 72 B-body.

?

 

[DrCharles]

how are you gonna plug weld the front?
add plates to it?
did you make yours yet?
ill prolly get chopping on mine tomorrow, and im excited to find if the 1/8th wall clears the rails

Yep, already made (cut and hammered by me, plates and rear seam welded by local shop).
It does clear the width, but requires just a hair of massaging and bottle-jacking at the rear.
These are the pics from trial-fitting before I trimmed the front plates and had them welded all around.

 

[diymirage]

im about to start cutting

can i bump the front up to the rails and weld the tube to it, or id the little plate essential?
(it seems to that adding that plate ads more of my welds and more options to fail)

 

[DrCharles]

The plate is advisable both to spread the load along the stamped crossmember, and because it's tricky to weld 1/8" tube directly to that sheet metal...

 

[diymirage]

The plate is advisable both to spread the load along the stamped crossmember, and because it's tricky to weld 1/8" tube directly to that sheet metal...

so the idea is to step down on the plate, maybe 1/16th?

i figured if i put a plate in, id cut a section of the box into two sections of angle iron and wrap one leg underneath it