Hey Miata people, help with some structural rust

We just had our 99 nb go in for upgraded sway bar mounts.  Rust/rot was found.  Does anyone make patches for this already done up?  Picture to follow.

Thanks

I haven't crashed a spec. Miata in a while but the last time I did, three years ago, all the stuff needed to re-clip it was still available from Mazda.  I'd start my search there.

am i crazy or isn't that the "frame rails" of the Chassis.. my immediate reaction would be to ask what the diminishing returns are on repairing that... if that structure up there isthat bad.. what's the rust status on other parts of the shell?

Ronald the crappy miata had rust on the lower rear rocker areas and this area was PERFECT, with absolutely no rust.



 

I have a customer with that same issue.  Haven't done any research, but does anybody sell front cuts from Japanese models?  I wondered if they might sell engines, then have frame rails left over.

Not much rust elsewhere on mine, but it's a big job.  That's not getting fixed with the engine, suspension and fenders in place. 

spacecadet (Forum Supporter) said:

am i crazy or isn't that the "frame rails" of the Chassis.. my immediate reaction would be to ask what the diminishing returns are on repairing that... if that structure up there isthat bad.. what's the rust status on other parts of the shell?

Ronald the crappy miata had rust on the lower rear rocker areas and this area was PERFECT, with absolutely no rust.



 

That was my first thought. I can only imagine how nasty the rest of the car must be, but that picture alone makes it look like it's not worth saving. Especially if you aren't doing the work yourself.

the rest of the car is in pretty good shape.  the suspension is great, roll bar.  The engine is 200k plus but still running fine.

Def some rust on the rest of the car, but I would like to save it.  There really isn't rot elsewhere, especially for a  new england car.  I think this place just caught all the salt over the years.

You'd really scrap it?

In reply to thedoc :

Unless you don't mind tearing the car apart and doing the welding yourself - very likely after building a chassis jig so you can weld parts of the front in straight - I think it's reached the end of its useful life. At shop rates you can probably get a better car from down South for the same or less money than it would cost to fix this properly.

Few ways to proceed depending on how meticulous you want to be.

If you own a welder you can fix anything. Strip away all the parts that are in the way. Cut out the rot and form new tin. It is mostly jhust a folded piece of 16 gauge? Chances are this wont be invisible, but it can be solid.

Second is to find a donor and cut out the rotted piece and graft into your car. This has the potential to be near invisible to most people. Since it is in front of the spring tower, it wont require a ton of due diligence to not mess up the chassis alignment.

Third methos is to do an entire front clip. Ignore the non Miata body and focus on the Miata front clip that I separated from the Miata firewall. This came apart with a drill and a chisel/hammer. It was a lot of brute force and ignorance work, but not rocket surgery. The whole thing plugs into the firewall via the circled stub on each side. You could do just one side if that is all you need.

OK, thanks

I have been told about a couple of fab shops locally, I will get some quotes and go on from there.  My mechanic wasn't overly freaked out, but we didn't talk price, etc.

Price is going to depend on who strips out whatever is in the way and them puts it back after the repair. Keep in mind that some parts will need to be in place so that the mounting locations cn be fabricated be they captive nuts or bracket.

I can't picture if this can be done with the engine in the car.

NBs rust in two main spots, the rear end of the rocker panels and the front frame rails. I repaired my last NB by cutting out the sides and bottom of the rails from the spring perches to the radiator support. I made up a 12 gauge trough by welding three plates together and welded the assembly in place. I had gone to the Mazda parts counter for proper parts but the cost was prohibitive. If you do decide to repair it with OEM parts get NA rails, they're single layer rather than double layer and aren't nearly as rust prone.

Edit: Had I had access to a brake I would have folded up sheet metal as NoHome suggested. 

Edit#2: I did mine with the engine and suspension in place.

The official repair method would be to buy the parts from mazda and replace the whole thing.  A few UK shops make repair panels just for this.  I don't know anything about them but here are a few links.

https://lucacarmods.com/en/shop/sheet-metal/mx-5-nb-chassis-beam-repair-panels-set/

https://www.ebay.com/itm/Set-of-Mazda-MX5-Chassis-rails-repair-panels-/223239373183

spacecadet (Forum Supporter) said:

am i crazy or isn't that the "frame rails" of the Chassis.. my immediate reaction would be to ask what the diminishing returns are on repairing that... if that structure up there isthat bad.. what's the rust status on other parts of the shell?

Ronald the crappy miata had rust on the lower rear rocker areas and this area was PERFECT, with absolutely no rust.



 

Funny- it must be an "or" thing- after 15 salty winters driven every day- the rockers are destroyed.  But the front frame rails are fine.  How that worked out is a mystery to me.

Guys, thanks so much for the input and help. I'm starting to get sick about this car.  I will get a couple of local quotes and proceed from there.  I don't have time for a project right now.  We are also wondering about getting a car from down south or a garage queen here.  This car has been such a pleasant experience and a real father son bonding vehicle.  My son just graduated from high school and this car was voted best car.  He is known for cruising it all over town.   The first year we had it, he put ten thousand miles on it himself.

Dang, I really hate new england's penchant for rotting cars.  I have protected my mustang for this very reason, it is still pristine underneath.

Anyway.  I will check things out and get back to you with a report.

Thanks

In reply to thedoc :

Seriously, even factoring shipping or your time/fuel to come fetch this, drag it back home, and swap all your parts over, you'd still be way ahead in time and money spent. 

In reply to Pete Gossett (Forum Supporter) :

That's the sort of thing I should do with my supercharged Miata. It's a fun  car but rust is showing in all the usual places for an NB, including the frame rails.

In reply to DeadSkunk (Warren) :

I've completely stopped sharing all the cheap Miatas & chassis donors because there's just so many of them. 

In reply to Pete Gossett (Forum Supporter) :

How do you find them?  Just in case I need to replace mine....

In reply to alfadriver (Forum Supporter) :

FB doesn't seem to allow people to search outside their local area, so it's probably easiest to put the word out to us southerners with your parameters & see what we can find. 

Wow, you guys are great.    Pete, thanks for finding that car.  I'm not in the spot to drive down and pick it up, but that is a fantastic idea.  My son is being a bit more practical than I am. The car has 200 k on the engine, but is doing fine with the exception of increased oil consumption.  

I will get back to you when I get some quotes.  I would have NO problem stripping this car out and having the work done.   My son however, is more of a driver and not fixer.  I might let him decide how far he wants to go.  When I was a bit older than he is now, (many years ago) I had a love affair with a dead bug eyed sprite.  I rebuilt and restored that car.  It was awesome for me.  He has loved this car from the moment he saw it.  We have had some absolute great father son times in the car and he has done some really nice auto cross in it.  I'm just sick to let it die.  If it comes to it, I'll button it up for the winter and figure out time and money from there.

Good night Pete,  if it were me, I would do whatever to get the car from LA.  I just do not want to do a project for my son's car that he isn't going to be excited to finish.  Sadly the kid has had a nightmare working on most of the cars in out fleet as we always get bogged down by rust.  My miata and my 06 mustang are pleasures to work on, but he has never been around for those projects.

Guys, big thanks

Got a friend patching up his NB with that exact issue, but hes DIYing it. 

Pete Gossett (Forum Supporter) said:

In reply to alfadriver (Forum Supporter) :

FB doesn't seem to allow people to search outside their local area, so it's probably easiest to put the word out to us southerners with your parameters & see what we can find. 

I did a search in Biloxi after seeing this thread this morning. On my FB Marketplace page I can type in any town I want and get a 100 mile radius.

Death kart?

Hey Guys,

 I was able to have a welder check out the car.  He said we def could fix it, but was worried about what else we would find when we stripped the car to get it ready.  He gave a high quote of $2000, with us doing the tear down.  Honestly, If I had the space to do this, I would.  My wife, however is adamantly opposed to the repair.  The engine is using more oil and starting to smoke.

So we are on the hunt for a new (er) car.  If we do not get another miata, I will take all of the great stuff off this car and put it on mine.  We are looking for an na or an nb, but I am trying to give my son the chance to make this about him and not me.  At least now we know where to look for rust.  I had looked for rust with this car.  Honestly, it looked so good I wasn't worried.  I did not remove the plastic shroud that hid this rust, now I know.

Thanks for your advice.  I will let you know when we play  taps for this car.  Whoever is in new england, I'll let  you know when we part the car out.