NS F355 Project (Page 14/73)
Yarmouth Fiero JAN 25, 08:54 PM
Thanks Blooz. Great shots. I think if I remove the 'Z' channel and let the transverse frame come up under the firewall / window flange, it should be safe. That puts the transverse frame flush with the upper frame rails as well so they won't interfere with the body in any way.

I just modeled the stock hinges for my drawing. I think the 84 wire glands in the fire wall are in the same general loaction as my 85.

Your 308 doesn't have a 3" frame stretch does it? I may have even more room.

[This message has been edited by Yarmouth Fiero (edited 01-25-2013).]

Yarmouth Fiero JAN 25, 09:00 PM
Here is the arrangement with the transverse frame raised up under the firewall window ledge and the stock hinges in place. I'll have to compare your 355 body measurements with my drawing and see where the new hood will lie in relation to the top of the firewall. I figured there will be no body work forward of the engine deck cover so I'll have to fabricate some sort of cover for the base of the hoops.
Bloozberry JAN 25, 09:07 PM
That's true, the 308 is stock wheelbase so you'll have even more space. Also, the wires pass through in the same location as all years, it's just that I had a senior's moment for a second. I knew something about the '84's wire bundle was different but now I realize it's not where the wires pass through the firewall, it's where the big C500 connector is. On the '84's it's on the firewall, but I remember now that I moved C500 to the same place near the battery as the later years. You'll be fine.
Yarmouth Fiero JAN 25, 09:12 PM
Great news.

I'll use your 65mm and lay a temporary engine deck on my drawing and see how it looks in relation to the top of the firewall and the roll over hoops. This weekend we will remove the rear window... finally. That sucker is stuck on there something fierce.
Yarmouth Fiero JAN 25, 09:33 PM
I added an engine deck surface just to have a look and while it seems high using your 65mm measurement, it appears that its only 3/16" higher than the stock Fiero engine deck. Maybe 355fiero or others who are farther along can confirm this. Regardless, I will definitely require some sort of fairing to cover the top of the firewall around the roll over bars.
Yarmouth Fiero JAN 26, 07:30 AM
Hi Blooz..... to answer your question about connecting the transverse frame to the upper frame rail, I have added an angled flange 1/8" thick that will cap the transverse frame and wrap up over the top of the upper frame rail. This should give ample surface area to allow a wrap around weld (atleast were its possible to get at). I have shown the inner flange of the upper frame rail snipped away to make room for the angled flange to fit tight to the body of the upper frame rail. Also, I have removed the 'Z' piece from under the firewall flange to allow the transverse frame to sit flush with the top of the upper frame rail.

Its unfortunate that the top flange of the fire wall will prevent me from welding the whole assembly together before dropping it down into place. I don't really want to cut the top of the firewall off to allow that to happen....... but

Thoughts?



[This message has been edited by Yarmouth Fiero (edited 01-26-2013).]

Bloozberry JAN 26, 08:17 AM
IMHO, the weakest part of the Fiero chassis is how the rear upper frame rail is attached to the cabin. To begin with, there doesn't appear to be much of anything for the uppers to be attached to in the first place. Perhaps that's because GM wanted the rear section to be frangible from the cabin in the event of a hard t-bone collision on the back side, but then that might be giving GM too much credit.

I think your latest idea is good but it might be stronger to leave out the angled flange (grey piece) and leave the back and top faces of the new beam longer. The longer top section of your new beam would overlap the top of the upper frame rail similar to your current grey flange, and the longer rear face of your new beam would be bent backwards 90 degrees to give greater contact with the inside upper frame rail. You'd have to trim a little more of the weld flange on the inboard side of the frame rail, but that's not a big problem.

One other thing I noticed is that your latest drawings don't include the support brace that interconnects the underside of that joint to the lower frame rail. That will make a huge difference too.
Yarmouth Fiero JAN 26, 08:30 AM
I agree Blooz. Its quite shocking just how poorly the upper frame rail is installed. The only problem with leaving out the flange and leaving the transverse frame longer to overlap the upper frame rail is that its going to be tough getting it in there, especially if I leave the front of the transverse rail longer. As I have it now, it would slip right into place between the rails. I'll have another look. Yes, I left the vertical frames out for clarity to see the flange. I think once they are all in and tie all 4 frame rails together with the transverse frame as well as add the large gussets against the firewall, the chassis is going to be incredible strong and stiff.... much more so than the original chassis ever was. I hope I never regret builting it to NOT come apart in an accident.

[This message has been edited by Yarmouth Fiero (edited 01-26-2013).]

Yarmouth Fiero JAN 26, 08:35 AM
OOps.... I just reread your comments. I understand now, yes, leave the back face of the transverse frame long and bend it back 90 degrees. I agree with you 100% now. Plus its easier to build and less welding with the extra flange taken out of the design. Thanks for your thoughts. I'll update the drawing.
Yarmouth Fiero JAN 26, 08:54 AM
Ok, I have removed the mounting flange and extended the transverse frame and formed 3 mounting flanges with two of them bent back 90 degrees. This should still slide into place nicely.