MileHighDart
Well-Known Member
I have considered adding something on top as well.
Has anyone successfully used the USCartool A500 Crossmember?
- Thread starter MileHighDart
- Start date
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goldduster318
Overzealous Car Modifier
Since I actually have an original piece in the garage, and a piece of 1/4" x 1 1/4" mild steel, I went to see what I could bend:
By applying force at the arrow with my bare hands (I'm 6'/185 and work an office job, so I'm no body builder), I could put a radiused 90 degree bend in this steel bar no sweat. My bench isn't even bolted to the wall or floor so the force is pretty low. I could also bend it almost all the way back before the table moved. The moment arm here is 6" or so, so not huge.
I pushed as hard as I possibly could at the arrow on the factory piece and I couldn't get any permanent deformation, it only flexes a tiny bit. I even moved my table. No way is that going to be stronger than the factory piece. My shadetree garage test is also showing that direction. The floors on these cars are pretty weak so it's not doing much.
You might be able to "get away with it" being dependent on the lower piece (which is bolt in so it may move somewhat just do to that), given that the lower piece is no doubt pretty stout. I don't think any of us would build a frame rail, roll cage or subframe connectors out of a flat bar with a bend in it. They're always tubing. When this is welded to the floor it's approximating a box tube.
You'll see that in my crossmember they use some plate welded at 90's to get a similar shape, it doesn't deflect either. Remember I also had my floor cut out to do my swap and the whole thing becomes a lot more floppy. I also have subframe connectors. Not much holds the car together between the left and right rails, why make it any weaker? I know it's difficult for people to redo their whole floor due to that, so do what you want. I just don't recommend it.
jos51700
Green Bearing thread connoisseur
That flat piece contributes virtually nothing to the structure you've removed, regardless of what others 'get away with' and regardless of adding subframe connectors or anything else, assuming you're still running torsion bars.
Think about it like this: let's call the factory crossmember an 'n'.
The torsion bars are anchored on the legs of the n. The twisting motion from suspension action (reminder, equal and opposite reaction) is transmitted to the legs of the n by the torsion bars. The strength on the n comes from the thickness of the n as you look at it from the front or rear. That piece you made is 1/4 thick. The factory cross member "thickness" (of the shape, not the metal) is what, an inch? Inch and a quarter? Inch and a half?
And you reduced that, significantly. That piece you made doesn't bring that thickness back, and you can't because the transmission is in the way. Your best alternative is to replicate the n shape, but with thicker metal.
Explaining another way, cut a sheet of metal in a n shape, lay it flat on a table and try to bend it to touch the legs together while it stays flat (I.e. in plane). The metal keeps it's strength when the load applied to the edge, in the direction of the sheet (if that makes any sense at all.
The only reason the factory had the piece in there that you replicated is to hold the two n's parallel to each other so they can't buckle.
The photos with the b callouts is terrible.
What you want is thicker metal in section, like motor plate shown.
Subframe connectors don't do much. Rectangular box sections kinda stink in resisting twist along their own axis, and sure the car will go back together with the mods you've made but remember: strength and fatigue are two different things. That crossmember will flex more. More flex equals fatigue, which will work harden the metal and eventually result in cracks. The lower transmission mount crossmember adds some box section to the whole deal but if it's not designed and mounted properly, you went from bad to very dangerous!
I hope that makes sense and the pics load. I replied on my phone, which is terrible.
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plumkrazee70
Well-Known Member
I'm not an engineer and I can appreciate the tests you've done. But here's the thing, I can recall at least three members here that daily drive their cars with the A500/518 and modded the tunnel the same way as above and I believe have had no negative effects.
@TrailBeast @Junior340 @gdonovan either of you want to weigh in?
@TrailBeast @Junior340 @gdonovan either of you want to weigh in?
TrailBeast
AKA Mopars4us on Youtube
True enough, been daily driving it for years with zero movement.
jos51700
Green Bearing thread connoisseur
It's good to know that the hole you cut in the floorboard so you could watch the crossmember while you drive didn't affect the rigidity, either. ;-)
TrailBeast
AKA Mopars4us on Youtube
No hole in the floor here.
I just cut out the hump in the loop above the trans and left the two remaining straps.
Welded in .085 wall 2x3 frame connectors help support the torsion bar support part of the equation.
MileHighDart
Well-Known Member
Time for an update.
Got the trans bolted up for a final test fit. First time its been in and actually supported by the new crossmember and mount.
I'm attaching a shot of what the USCartool member looked like right out of the box, and then a picture of what it looks like now after much cutting, grinding, and moving the inner holes out.
Then a couple pics of the trans/crossmember in place, and pics of the clearance I have on pass and driver sides.
It still has to come back out so I can weld in my re-enforcement hoop. And the converter is not on the trans right now.
Just took measurements for getting my driveshaft shortened. Hopefully drop that off to the shop next week, but with Christmas who knows if that will happen.
Got the trans bolted up for a final test fit. First time its been in and actually supported by the new crossmember and mount.
I'm attaching a shot of what the USCartool member looked like right out of the box, and then a picture of what it looks like now after much cutting, grinding, and moving the inner holes out.
Then a couple pics of the trans/crossmember in place, and pics of the clearance I have on pass and driver sides.
It still has to come back out so I can weld in my re-enforcement hoop. And the converter is not on the trans right now.
Just took measurements for getting my driveshaft shortened. Hopefully drop that off to the shop next week, but with Christmas who knows if that will happen.
Hemioutlaw
Make America Great Again!
Congrats,
Look's like your getting there.
As we all know that work on customized stuff, it seems like everything's a PITA but that said, this threads not exactly a beaming review for USCartoon's fitment and that all speaks directly to the fixturing used for manufacturing.
67dartgtgo
Well-Known Member
That’s very nice work. I can’t wait to see the final fit. Thank you for posting these great pics. Looking forward to more.
MileHighDart
Well-Known Member
Well, tried to drop my driveshaft off today. Sign on the door, closed through thursday. So Guess I'll have to wait till friday on that.
Couldn't leave the crossmember bare metal, so threw a little paint on it. Paint is good cause that means I'm done messing with the crossmember.
Couldn't leave the crossmember bare metal, so threw a little paint on it. Paint is good cause that means I'm done messing with the crossmember.
plumkrazee70
Well-Known Member
Looks good! Can't wait to see it up there.
jrlegacy23
68 Barracuda
I cut mine center section out like this. When I put the 3/16" or 1/4" thick piece (I have both) in place, I will weld it to the factory bracing. I have a piece that will fit into the opening. In my mind this will help with the structural force and integrity of the factory piece.
MileHighDart
Well-Known Member
That looks like it will probably work, as you've probably noticed, the A500 trans is wider on the drivers side than on the passenger side, mainly in the overdrive section, which is where the mount is. I drew a circle on one of my pics to show the area where I have the least clearance. It's about 1/2" right now, but after welding in my 1/4" thick brace, I will be down to around 1/4" clearance there. Would be nice if there was more room to build something more like it had originally, like a box, or channel structure if you will, but just no room for it. If you look at the pic of my trans I drew a box around the side of the overdrive area. This area is sticks out roughly 1" - 1-1/4" farther than the other side of the trans. This is also why I had to do more trimming on the drivers side of the uscartool crossmember.
jrlegacy23
68 Barracuda
I think I can "shallow box it" loike 1/4", but I will look a little more into it on my test fitting. Thanks MileHighDart
MileHighDart
Well-Known Member
Well the next step is under way. Just dropped my driveshaft at Boulder driveline services, to get it shortened. 45-3/8" is what I came up with for the length. Hope I got that right. Measured it like half a dozen times.
He said probably less than $150.
He has to replace the rear yoke. My drive shaft is fat for most of it's length, then necks down near the ends. Because of the amount he has to remove he'll have to get a yoke to fit the fatter part of the shaft.
He said probably less than $150.
He has to replace the rear yoke. My drive shaft is fat for most of it's length, then necks down near the ends. Because of the amount he has to remove he'll have to get a yoke to fit the fatter part of the shaft.
MileHighDart
Well-Known Member
alright, i'm in... you guys have talked me into it
MileHighDart, did you do anything to the body seam at the front of the transmission tunnel?
Not a thing. It might make it a little easier to get onto the upper bell housing bolts. But I was able to get them pretty easily by unbolting the transmission crossmember, letting the trans down a bit and then I was able to get to those bolts quite easily from the bottom, with a very long extension and a swivel socket. Before tilting the engine/transmission down at the rear, I removed my distributor just to make sure it didnt hit the firewall. I let it down just about to the point that the oil pan was going to contact the steering drag link.
cool, just like any other 727, at least on that end
MileHighDart
Well-Known Member
A little progress. This turned out to be one of the most difficult parts of the swap so far.
Started this on the press at work, got the basic shape but not right.
So I made a cardboard template, then trimmed 1/4 off the template around the sides and top, but not the bottom. Then transferred the template to a bunch of old 2 by 4's nailed together. Cut it out on my bandsaw. Spent a bunch of time hammering on this with a bfh, some with the metal around my form, and some on the bench, then check the fit on the form.
Think its ready, just need to get my butt out there, drop the tranny back out and test fit this thing, and get her welded in.
In the first pic it looks like it doesn't fit the form, but thats just cause a piece of the wood chipped of when I was beating the crap out of it...ha ha
Note: I didn't cut this metal to length, just a scrap I had around and it turned out to be exactly the right length.
Started this on the press at work, got the basic shape but not right.
So I made a cardboard template, then trimmed 1/4 off the template around the sides and top, but not the bottom. Then transferred the template to a bunch of old 2 by 4's nailed together. Cut it out on my bandsaw. Spent a bunch of time hammering on this with a bfh, some with the metal around my form, and some on the bench, then check the fit on the form.
Think its ready, just need to get my butt out there, drop the tranny back out and test fit this thing, and get her welded in.
In the first pic it looks like it doesn't fit the form, but thats just cause a piece of the wood chipped of when I was beating the crap out of it...ha ha
Note: I didn't cut this metal to length, just a scrap I had around and it turned out to be exactly the right length.
Nice. Kim
MileHighDart
Well-Known Member
As far as engaging Overdrive and Converter Lockup I'm going to keep it very simple.
Two rocker switches on my console, one for each function, so I can flip them on or off as needed.
Fully automatic operation would be cool, but I think this will work fine for my driving style.
Basically 90% of my driving is on the highway. I'll just run it as a 3 speed when in town, and then flip them on when I hit the highway.
Just ordered a couple lighted rocker switches from rockerswitchpros dot com. And a couple of custom actuators that read Overdrive and Lockup.
Two rocker switches on my console, one for each function, so I can flip them on or off as needed.
Fully automatic operation would be cool, but I think this will work fine for my driving style.
Basically 90% of my driving is on the highway. I'll just run it as a 3 speed when in town, and then flip them on when I hit the highway.
Just ordered a couple lighted rocker switches from rockerswitchpros dot com. And a couple of custom actuators that read Overdrive and Lockup.
plumkrazee70
Well-Known Member
Very nice. I am not looking forward to making the that tunnel piece. I don't have access to fab tools.
jrlegacy23
68 Barracuda
Same here, but I will make do with what I have. I took a piece of 1/8", a little more bendable piece to fit into place. Then bringing it to a friend who will match it for me.
moparlvr166
Well-Known Member
MileHighDart,
Check into a high low vac switch, (will cut 12 v power when on decel or hard accel).
I did this a long time ago, they were on some early 82-83 diesel GM trucks with the 700r4 trans. I don't know if still available, possible other diesel trucks with lock up T/converters in early to mid 80's trucks.
Check into a high low vac switch, (will cut 12 v power when on decel or hard accel).
I did this a long time ago, they were on some early 82-83 diesel GM trucks with the 700r4 trans. I don't know if still available, possible other diesel trucks with lock up T/converters in early to mid 80's trucks.
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