So the plan is to grind the rusted areas off the front passenger side frame rails build a steel cast out of 16 gauge metal and weld it on with my mig????

am i crazy? advice

 

Sounds like a plan, Stan... er... Rick.

Minus the fact that 16ga steel won't do ish for strength (0.0598" thickness). Use thicker plates.

 

haha Marc, i elected 16 gauge b/c i called one of the place that sells replacement rails and they said the use 16 gauge what do u suggest?

 

1/8" (0.125") 11ga is the normal thickness for frame rails. The 280zx frame rails aren't the main structural support, the rockers are, but if you are going to all that work, time, and cost, you might as well make it solid.

I haven't done my rails, but they need it. I did replace both rockers, floor pans, and installed a ttop roof, and when I corner super hard, I can hear my body clicking and tinging from the stress. Not too long ago someone posted cockpit video of their 280zx during auto-x... and you can totally hear the body flex.

 

A little late on this.16ga is actually thicker than what was originally there.I just made my self some replacement floor supports as that is all they are from 1.5 X 3.00 mild steel tubing and made 1 x 1 angles to fie them into the floor similar to how the factory had them.Based on the good metal that was left in what I cut out of my 82 the original rail was.041 thick this is 19ga.The floors were .034 or 20ga. I bought just under a half sheet "drop" for like $35.00 and a 20 foot stick of 1.5 X 3 X .072 tubing for $80 I also have an 81 turbo that needs the same work too.This is pretty much enough syuff to fix both cars.I also bought a HF 30 inch brake to bend my angles on.Hope this helps somebody.More pics of my project are here. http://www.facebook.com/media/set/?s...7523353&type=3

 

how much structural strength is in the firewall? Ill post some pics soo as i jack it up.. also whats the best way to jack a zx?

 

The strength is in the rockers (like Nismopick said) and in the abc pillars and roof. When I welded a t-top roof on my 79, I welded a piece of sq. tube from the bottom of b-pillar to b-pillar. Then I set a 2x4 across the middle of the bottom and braced it, so when I cut the roof off it wouldn't sag. It didn't at all. So you may not need to do anything but I wouldn't risk it. The car acts like a box, firewall, roof, floor, sides, and back. take away one of those and you have a floppy mess. The problem I see is where to brace it so you can still work. I would think if you braced the rockers enough the roof and firewall would hold everything fine. I will be doing this my self soon because my rails are destroyed. So I'm very much wanting yours to work so I know what to do with mine.

 

If you do not remove any of the rockers and just the rails or the bad part of the rails and floor section you should be fine.I put my car up on ramps in the back and front and added solid concrete blocks under them to get a comfortable height.This kept all of the stress in the proper places.I only did one side at a time.Like it was stated above the strength is in the rockers and tunnel as far as the floor goes.

 

I did the front halves of mine several years ago, and parts of my floor, with 16 ga and its definitely thicker than was there. I know its ugly, but I like to make two "sides" and then a bottom piece that I have to hammer on. It seems very stiff doing this. If I were to use the tools and skills that I have now to do it again, I think I'd take a more comprehensive approach and replace the full length of the rail and the floor all at once. Doing it piecemeal takes a really long time.

Pictures:
Z Car Project :: Subframe Repairs