Building an inner frame stiffener

[tinydb84]

I have a build thread on here but as the site is so huge I am making a specific thread here so I can get more input.

My build was supposed to be a mild rebuild with a static drop...then it kinda got out of hand and is turning into something that could handle pretty well. I was in the process of building a trans crossmember and decided that I want to build an inner frame stiffener out of it (because why not?). I have set most of it up to lay rocker, and would still like to do so.

I have been looking at Porterbuilt's parts and plan on "borrowing" some ideas from him. Since I already "borrowed" ideas from Rob at No Limit and The Astronaut.

Here is where I am at:
4'' Z with 2.5'' SFBD

Lower ball joints moved forward 5/8''

Crossmember sectioned to drop the engine 2.5''

Engine moved back 3'' to clear the steering center link

Running a 5.3/4l80 that will be turbo with fender exit exhaust so I have plenty of space underneath.


Here is the start of my trans crossmember:


Questions for all you engineering types out there....

I am going to do the forward bars next. I can run them all the way just past the front body mounts (I will have to fill and patch the parking brake section on the frame). The other option would be to mount them at the body mounts or just before them. Any rational for each position? Is there a significant benefit to gusset where the tubes tie in? Say dimple die 1/8'' plate?

I only have 4 inches of frame height to mount the inner section too. I would assume it would be better to make the mounts bolt in at different heights along the frame to give it more "structure" (I dont know a better term for this). This will eventually also extend rearward once I start doing my four link.

Lastly, I have access to my neighbors tubing bender but....he only has 1.25'' dies. I could also just buy the tube and have a local shop bend it for me. Would there be a significant benefit to going 1.5 over 1.25? Stylistically do you think it would look odd with the center bars being 1.5 and the forward (and eventual rearward) bars being 1.25''?

[PBFAB.COM]

Originally Posted by tinydb84

I have a build thread on here but as the site is so huge I am making a specific thread here so I can get more input.

My build was supposed to be a mild rebuild with a static drop...then it kinda got out of hand and is turning into something that could handle pretty well. I was in the process of building a trans crossmember and decided that I want to build an inner frame stiffener out of it (because why not?). I have set most of it up to lay rocker, and would still like to do so.

I have been looking at Porterbuilt's parts and plan on "borrowing" some ideas from him. Since I already "borrowed" ideas from Rob at No Limit and The Astronaut.

Here is where I am at:
4'' Z with 2.5'' SFBD

Lower ball joints moved forward 5/8''

Crossmember sectioned to drop the engine 2.5''

Engine moved back 3'' to clear the steering center link

Running a 5.3/4l80 that will be turbo with fender exit exhaust so I have plenty of space underneath.


Here is the start of my trans crossmember:


Questions for all you engineering types out there....

I am going to do the forward bars next. I can run them all the way just past the front body mounts (I will have to fill and patch the parking brake section on the frame). The other option would be to mount them at the body mounts or just before them. Any rational for each position? Is there a significant benefit to gusset where the tubes tie in? Say dimple die 1/8'' plate?

I only have 4 inches of frame height to mount the inner section too. I would assume it would be better to make the mounts bolt in at different heights along the frame to give it more "structure" (I dont know a better term for this). This will eventually also extend rearward once I start doing my four link.

Lastly, I have access to my neighbors tubing bender but....he only has 1.25'' dies. I could also just buy the tube and have a local shop bend it for me. Would there be a significant benefit to going 1.5 over 1.25? Stylistically do you think it would look odd with the center bars being 1.5 and the forward (and eventual rearward) bars being 1.25''?

Post up a drawing of what you have planned. I would be happy to offer some advice.

Nate

[tinydb84]

Man, the only thing worse than my welding is my paint skills....

Black are the frame rails and body mounts
Blue is the trans
Red is the trans crossmember I made already
Green are the bars I am thinking of adding
Brown would be the gussets at the tie ins.

Would 1.5'' tube offer significant benefits over 1.25''?
Any benefit to pushing the forward tubes as far forward as possible vs being connected at the body mount?
Are the gussets worth it?

Thanks for the input Nate. Hope you don't mind me copying your ideas. Don't worry though, I will be ordering a dropmember for my 66 once this truck is done.

[PBFAB.COM]

Originally Posted by tinydb84

Man, the only thing worse than my welding is my paint skills....

Black are the frame rails and body mounts
Blue is the trans
Red is the trans crossmember I made already
Green are the bars I am thinking of adding
Brown would be the gussets at the tie ins.

Would 1.5'' tube offer significant benefits over 1.25''?
Any benefit to pushing the forward tubes as far forward as possible vs being connected at the body mount?
Are the gussets worth it?

Thanks for the input Nate. Hope you don't mind me copying your ideas. Don't worry though, I will be ordering a dropmember for my 66 once this truck is done.

Don't worry about "copying" me.... there's no hard feelings here! Lots of good ideas out there, and why not learn from somebody else's knowledge/experience.

I would make the tubes connect and tie together... it might just be your paint skills.... but it looks like the front x-tubes end at the first crossmember and the rear end at the second.

Nate

[tinydb84]

Didn't think of that. Good catch. I'll add that in. Anything else I should do?

[PDXsquare75]

Hey guys, is this thread dead? I know it's a bit old , but I have been coming up with vertually the same design for frame stiffners. I was just hoping that there was more or some completion pictures. Maybe some fallow up on the performance/effectiveness of the trans cross member/ frame stiffners.

Any info would be great.

On a side note (I am not an engineer) but the 1.25 tubing should be fine as long as you go with a thicker wall. Maybe like .125, or .180 at the most.

[tinydb84]

I figured I would necro this thread since I finally got around to working on it. The old photobucket pictures don't work so here are just the picks of the current progress.

Here is the basic idea
20180624_193507
Added bars to the rear close to the upper 4 link mounts.
20180630_151657
Added the forward bars
20180707_161612
Got two more bars added to the front body mounts. Going to add two more to the rear and tie the rear body mounts in then I think I will be done with the center section.




Thoughts, ideas, criticism? I am happy to learn.

[chevy_mike]

My first thought off the bat is, now the trans cross member is non removable, once the cab is on, pulling the trans if you ever have to, is going to be a royal PITA.

Second thought is, you really haven't left a lot of room for the exhaust system, especially since you are laying frame. Exhaust cannot be any lower than the bottom of the frame. With the front bars and the cross member, these would be in the way to route the tubes. No idea where the mufflers would go with the rear bars.

My personal opinion is, you should have finished the exhaust and then figured out your bars. The work itself looks very well done.

[tinydb84]

Thank you Mike. I appreciate the input.

The center cross member will be removal. I kept it solid because I don't think I can weld it all in straight if it was three pieces (and I didn't have enough tabs at the time).

I had thought about the exhaust quite a bit. I am running a turbo set up and plan to do a fender exit.

I played with the idea of tunneling the cab near the trans but I am going to see how loud/smelly it is on the fender first. I have the space where the gas tanks originally were to hide a muffler if need be.

[chevy_mike]

Cool, sounds like you have a solid plan.

[tinydb84]

Here is what I ended up with for the transmission.

Everything else is welded in.


Pretty much done unless someone has suggestions otherwise.

[dec010974]

David is always working. 👍