Frame Rail Patch Yes or No?

[Zed Head]

The rails on a Z are actually just unibody reinforcement pieces.  So they are much thinner than a true frame piece would be.  Every piece of sheet metal in a unibody has some effect on body stiffness.  The most important structure is probably the rocker panels.  They are steel tubes, formed from sheet metal.

Lots of flimsy Z's out there and many ways to make them stiffer.  Think holistically.

[Yarb]

I understand completely. This is the first 280 I’ve owned. We had 3  240’s at one time back when I was a lot younger. They had the rail damage back then but most of it was from PO jacking it up in the wrong place. We’ll see what we’ve got when I post the pictures.

[Yarb]

Poked around with the ice pick today. Visually I can see some rust crawling up the side in the affected area as grannynot mentioned. Did not find any other soft spots beyond that area. Should have my borescope on Sunday. Did not get a response back about purchasing sections of the rail. Only other option would be to buy a complete rail and section out what I need. 

[Mark Maras]

 Or buy new rails and replace the old ones. I'm sure you'll find a rusty mess inside those rails. By the time you figure out how to treat all the rust in hidden places and insert new sheet metal in the holes, it's easier to replace the rails. The worst part is over-head welding but at least the rails are skip-welded. They weren't heavy ga. sheet metal and it doesn't take long for rust to thin them from the inside out.

[Yarb]

Purchased a set of rails from Bad Dog Parts.Has anyone installed a set of these on a 280Z? Looking for some tips for the installation. They are designed to fit over the existing rail. In my pics you can see a tab that’s welded horizontally across the rail. Even if I cut off the ears the rail won’t fit flat onto the rail. Any advice would be appreciated. Thanks

[Mark Maras]

I wouldn't weld them on over rusty rails. I'd replace the old rails with new ones.

[ConVerTT]

45 minutes ago, Mark Maras said:

I wouldn't weld them on over rusty rails. I'd replace the old rails with new ones.

Agreed 100 percent. @Yarb - how solid are your floors?  Did they pass the ice pick test?

Edited April 28, 2020 by ConVerTT

[Yarb]

Yes, only that one area is bad. Checked both sides with endiscope. Everything else on the car seems to be fine.

[ConVerTT]

22 minutes ago, Yarb said:

Yes, only that one area is bad. Checked both sides with endiscope. Everything else on the car seems to be fine.

Excellent.  So I agree with @Mark Maras.   Since the floor is solid I would just peel off the old rail and weld in the new ones

[Dave WM]

here is a thought, depending on your welding skill, get some sheet steel, try cutting and patching, I would do that just to see if I can weld well enough, Practice on the patch. IF it all looks good and you find no other evidence of rust with the bore scope you have a win. IF the patch process turns into a cluster, then you still have the rails that you can give a try or find a welder with the skill level needed. My only exp with welding is a cheapo HF flux core welder I used for some exhaust work, I had no idea what I was doing, but after a LOT of welding and grinding off bad welds it came out pretty well. I did a butt weld to round thin tube used in the exhaust, prob not the easiest 1st time MIG. So really depends on your skill level what you want do to.

[ConVerTT]

2 minutes ago, Dave WM said:

here is a thought, depending on your welding skill, get some sheet steel, try cutting and patching, I would do that just to see if I can weld well enough, Practice on the patch. IF it all looks good and you find no other evidence of rust with the bore scope you have a win. IF the patch process turns into a cluster, then you still have the rails that you can give a try or find a welder with the skill level needed. My only exp with welding is a cheapo HF flux core welder I used for some exhaust work, I had no idea what I was doing, but after a LOT of welding and grinding off bad welds it came out pretty well. I did a butt weld to round thin tube used in the exhaust, prob not the easiest 1st time MIG. So really depends on your skill level what you want do to.

Despite my earlier comment I also agree with this logic.   A patch could get you through the summer, or potentially much longer.  And then you could get the Bad Dog rails done when you decide you need a more complete tear down....

[Mark Maras]

 

6 minutes ago, Dave WM said:

here is a thought, depending on your welding skill, get some sheet steel, try cutting and patching, I would do that just to see if I can weld well enough, Practice on the patch. IF it all looks good and you find no other evidence of rust with the bore scope you have a win. IF the patch process turns into a cluster, then you still have the rails that you can give a try or find a welder with the skill level needed. My only exp with welding is a cheapo HF flux core welder I used for some exhaust work, I had no idea what I was doing, but after a LOT of welding and grinding off bad welds it came out pretty well. I did a butt weld to round thin tube used in the exhaust, prob not the easiest 1st time MIG. So really depends on your skill level what you want do to.

I agree. If you can master butt welding the thin sheet metal found on Zs you'll have little trouble with new frame rails. The exception being the overhead welding.