Project Greyscale 1971 Trans Am

[preston]

forget about the body.

Setup reference points where the rear LCA's mount, build some bolt in brackets with measure points if you have to. Worry only about the front LCA mounting points measuring correctly to the rear LCA mounts, both straight line and x-measurements. Obviously get your mounting height where you want it on the subframe first.

Maybe I'm not understanding your issue but it sounds like you are trying to align the subframe both with the rear frame and the body. Neither of those matter, you need it straight with the rear suspension mounting points. If after you do that you find the wheels not centered side to side of front to back in the wheel openeings you may need to modify the body openings or something else. But dont' let the original frame or body affect how you measure and bolt up the suspension mounting points. Get that correct and then worry about how it fits the body later. Move the sheetmetal if you have ot.

[bsharpe]

I found the issue with the subframe allignment. The scott mock subframe is not square. Unfortunately that is not ab easy fix so the project has been put off fir the last month. I finally removed the subframe and called ron sutton to figure out the next steps.

I had actually measured the subframe when others started posting issues but I only checked to see if the bare frame was square. My problem is with the lower control arm mounts which surprises me sinse I looked through all of scotts pictures and saw that th lower control arms were jigged.






Driver side



Passenger side

[raustinss]

wow there is some fine craftmanship that id want my name attached to. way to go scott mock ....only a 1" plus out over 4.5 feet LMFAO

[Build-It-Break-it]

Looking at your first picture you posted it looks like the lower control arm mount to the right has the control arm mounting point crooked. It looks like it's at a slight slant going through the cross member which would explain why that control arm is lower where you measured. If you look at the picture you can even see that were he triangulated the control arms isn't equal on either side.


Is Ron Sutton able to help you fix the issue? Or do you have to scrap the frame? You could still use most of the parts and buy a bare Art Morrison subframe if funds allow?

[raustinss]

hopefully someone can fix that sub-frame with new MUCH stronger lower control arm mounts, they don't instill any confidence by there appearance . my thoughts are there could be some gusset's added,figure with the loads that they would be or could be seeing might cause some deflection

[bsharpe]

Originally Posted by Build-It-Break-it

Looking at your first picture you posted it looks like the lower control arm mount to the right has the control arm mounting point crooked. It looks like it's at a slight slant going through the cross member which would explain why that control arm is lower where you measured. If you look at the picture you can even see that were he triangulated the control arms isn't equal on either side.


Is Ron Sutton able to help you fix the issue? Or do you have to scrap the frame? You could still use most of the parts and buy a bare Art Morrison subframe if funds allow?

Originally Posted by raustinss

hopefully someone can fix that sub-frame with new MUCH stronger lower control arm mounts, they don't instill any confidence by there appearance . my thoughts are there could be some gusset's added,figure with the loads that they would be or could be seeing might cause some deflection

I talked to Ron and feel very confident that he can help me optimize the C6 suspension for my car. Unfortunately he is booked up for the next 3 months which is longer than I can wait.

I am going to modify the subframe to make everything symetrical and stronger. As you noticed, the driver side lower control arm is angled. I will take a lot more measurements to verify everything but i hope the rear driver side lower control arm mount is the main problem. I am also going to relocate the swaybar, it isnt perfectly square and i dont like how the arms align with the lower control mounts. I plan to move it forward an inch on both sides.

Here are the pictures i found of Scotts Jig. The front of the lower control arms jigged but the rear tube is not.

[preston]

Hard to believe but its not unheard of for these subframes to be "out" I guess.

See post #2 where they talk about the front subframe. It looks like the same design used by a major manufacturer.

http://www.corner-carvers.com/forums...ad.php?t=48983

[Build-It-Break-it]

2 minutes into the video below he talks about the subframe

https://youtu.be/q6xU4je_XaE

[bsharpe]

Originally Posted by preston

Hard to believe but its not unheard of for these subframes to be "out" I guess.

See post #2 where they talk about the front subframe. It looks like the same design used by a major manufacturer.

http://www.corner-carvers.com/forums...ad.php?t=48983

I wish I had found that thread months ago(He doesnt identify the subframe so i couldnt search for it). They had the exact same problems as me. Not enough camber and non symmetrical lower control arm mounts. I could have saved hours of head scratching if i had known what to look for.

[preston]

I was assuming it was an AME based on the design,but now I see in your jig pictures that your guys' design is similar. The vorschlag car also had a 3 link subframe that looks exactly like and AME as well, so that's what I assumed, although frankly I have a very hard time believing AME would put out something with misaligned brackets. And its suspicious that it had the exact same problem as your sub frame too, at least it sounds like it.

I'm sure you could cut and repair yours if you were an experienced fabricator, but depending on what those things cost it might be best to just get another one. hard to say. Good luck.