What is it about the NBs that make them rust so much worse than NAs?

Car shopping for a friend.. Up here in CT we're running across a lot of NBs that have cancer all throughout their wheel rockers. That really surprises me, as I'm very familiar with NAs, and I'm used to their lower-rocker-panel/drain area rust issues, it's relatively rare to see an NA with rust at the 12 oclock position of the wheel well. Apparently this is pretty common on NBs.

What gives?

If it's properly repaired, will it return shortly?

I just repaired my NB at the 12 o'clock position driver's side. I'll tell you how long it lasts in the spring. My car also has 16 Michigan winters under it's belt.

It takes less time to drive to Atlanta and back than it does to patch rust. Just sayin...

(Plus you can throw in a track day at Road Atlanta and a nice steak dinner and still be time and money ahead.)

WonkoTheSane wrote: Car shopping for a friend.. Up here in CT we're running across a lot of NBs that have cancer all throughout their wheel rockers. That really surprises me, as I'm very familiar with NAs, and I'm used to their lower-rocker-panel/drain area rust issues, it's relatively rare to see an NA with rust at the 12 oclock position of the wheel well. Apparently this is pretty common on NBs. What gives? If it's properly repaired, will it return shortly?

Cant tell you why they rust in that spot or if in fact your perception that the NB rust more than the NA is factual.

What I can tell you is that a proper permanent solution is difficult on the Miata. Whenever you weld steel, the bead is going to be oxidized on the surface. This means that behind that skillfully executed butt joint and carefully metal finished repair, there is a seam of rust in the form of the backside of the weld. The plan would be to grind the backside down flush and coat with a protective coating. On a Miata you wont get near the backside of the weld.

If you just want another five years out of the car, then its no big deal to weld in a repair panel.

Tyler H wrote: It takes less time to drive to Atlanta and back than it does to patch rust. Just sayin... (Plus you can throw in a track day at Road Atlanta and a nice steak dinner and still be time and money ahead.)

That's how I see it. No more dealing with rusty northern hulks for me. I just need someone down there to inspect them for me before I make the drive....

NOHOME wrote:

WonkoTheSane wrote: Car shopping for a friend.. Up here in CT we're running across a lot of NBs that have cancer all throughout their wheel rockers. That really surprises me, as I'm very familiar with NAs, and I'm used to their lower-rocker-panel/drain area rust issues, it's relatively rare to see an NA with rust at the 12 oclock position of the wheel well. Apparently this is pretty common on NBs. What gives? If it's properly repaired, will it return shortly?

Cant tell you why they rust in that spot or if in fact your perception that the NB rust more than the NA is factual. What I can tell you is that a proper permanent solution is difficult on the Miata. Whenever you weld steel, the bead is going to be oxidized on the surface. This means that behind that skillfully executed butt joint and carefully metal finished repair, there is a seam of rust in the form of the backside of the weld. The plan would be to grind the backside down flush and coat with a protective coating. On a Miata you wont get near the backside of the weld. If you just want another five years out of the car, then its no big deal to weld in a repair panel.

That's why you use rivets/adhesives instead.

Or shop for a Miata from Arizona

I'm in Arizona, and I bought an NB from Nebraska. I always do things backwards...

Tyler H wrote: It takes less time to drive to Atlanta and back than it does to patch rust. Just sayin... (Plus you can throw in a track day at Road Atlanta and a nice steak dinner and still be time and money ahead.)

Better yet, a fly and drive, because we all know you can't go to hell without going through Atlanta Hartsfield first.

I might say that a lot of NBs came with Tupperware and NAs didn't.

Yeah, he'll probably end up with a southern car.. I've just been surprised because it seems like the rust is a lot worse on a 10-15 year NB than on the 15-25 year old NAs I see.

The good news is that this area is actually somewhat exposed in the trunk on the NBs, so it could be primed/etched/painted from in there.

I'd try to snag a car from as far down south as possible.

I would have thought that Miata owners in the northeast would do like many here in Michigan, put the car away all winter. I've seen at least three cars advertised today that have less than 40K on them and have never seen salt. One lady is selling a 16K Merlot NA that has been caught in the rain three times. I've bought three southern vehicles in the last 15 years, but a Miata is the one model I can find in great shape locally.

WonkoTheSane wrote: Yeah, he'll probably end up with a southern car.. I've just been surprised because it seems like the rust is a lot worse on a 10-15 year NB than on the 15-25 year old NAs I see.

I suspect the NA's that you are seeing now have been used far less in the winter.

I am guessing the NA's that got the same winter use as the NB's you are seeing were just as rusty at 10-15 years old. By the time they were 20+ years old they were probably bad enough to be scrapped.

Its just a theory though.

I first saw the rocker rust in the NA at almost exactly the 10 year mark in Canada. The newest NB is now that old.

The NAs that you see were imported from better areas because the local ones disappeared ten years ago.

I'm in PA selling my rust free southern NB, just picked it up last year, and it is so rust free I could even un bolt the exhaust without a problem, which was amazing as someone used to working on rusty northeast crap. We have too many cars now, need to move it along.

Sonic - pm me details.

DeadSkunk - we stopped to check out a 99 that had 32k on it.. Rusty!