1 2
dherr HalfDork
12/30/19 5:50 p.m.

I have a 1991 NA Miata automatic that we bought for the kids to use the last two summers as their wheels for the time off school. One has graduated and the other will graduate this spring and I am trying to decide what to do with it. I have four other two seat sports cars, so don't really want an automatic Miata, but there are several pros to this car that are making me have second thoughts about selling it.


Rust free NA Miata
Mechanically in decent shape, 140K miles, runs well for being an early 1.6
Recent soft top with glass window
Matching silver hardtop
A & B packages


Needs paint and minor body work as it was scraped in a parking lot down at ECU (according to our son)

Paid $3,000 for it two years ago, so we have had 20,000 miles of relatively trouble free driving (it did need a fuel pump and MAF while down at ECU). I am toying with making it a project since it is rust free, but don't want to spend a bunch of money on it unless I am keeping it.  So what would you all do with it? Sell it and spend the money on a more worthwhile project, or do the suspension, paint and install something interesting like a J32? I don't every see the automatic NA cars being collector items, but it is an early car in nice rust free condition.

thatsnowinnebago GRM+ Memberand UltraDork
12/30/19 6:19 p.m.

Sell it and the hardtop separately, then use that money and buy what you really want. Unless you really want a swapped Miata, in which case you've probably got a good candidate. 

chada75 Reader
12/30/19 6:29 p.m.

Swap a Manual in it.

dherr HalfDork
12/30/19 6:44 p.m.

In reply to thatsnowinnebago :

That is my first thought. Can probably sell the car for $2,XXX and the hardtop for $1200 as it is silver and in excellent condition.

dherr HalfDork
12/30/19 6:48 p.m.
chada75 said:

Swap a Manual in it.

That was my first thought, but how far down the rabbit hole do I go? 1.8 swap? or just keep it a 1.6? The auto to manual involves a bunch of things like a different ECU, wiring issues and of course the 5 speed and pedal box, drive shaft, etc.... So after all that work is a car that still needs paint and suspension worth the investment or just sell it and move on. I don't see that the cost of all the parts will be recouped in the resale price. I have found rusty running cars that would give me all the parts for the swap, but not sure the result is worth my time.

I think I answered my own question here......

penultimeta HalfDork
12/30/19 6:52 p.m.

Selling it and buying what you want makes the most sense here. However, I’m nonsensical when it comes to automotive stuff. If I had a clean NA Miata just sitting around, I’d 1.8 swap it with a manual with turbo down the line. 

Brett_Murphy GRM+ Memberand UltimaDork
12/30/19 6:54 p.m.

Turbo and upgrade the torque converter.


alfadriver GRM+ Memberand MegaDork
12/30/19 7:50 p.m.

In reply to dherr :

While not a high number, there are real people out there who need a Miata with an auto.  

I'd fish for finding one of those first- using the funds to find a better car to make the project you really want.

If that doesn't work, then proceed with the project you really want.

If it were me, I'd go with the 1.8l swap.  But finding a 1.8 car is a better start.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
12/30/19 8:03 p.m.

A manual swap on a 1.6 is cake. It’s about as hard as changing a clutch. It’s the 1.8 cars where things get difficult and the ECU gets involved.

Read me, but ignore the Alaskan guy who wants to rewire the car.


Rodan Dork
12/30/19 8:19 p.m.

Having done an auto to manual swap in a Miata, I'm in the 'sell it' camp.

As Keith said, it's an easy swap, but if the car needs other work it's going to be easier just to sell it.  Keep the hardtop for another Miata, or sell it separately... clean hardtops are getting pretty spendy.

dherr HalfDork
12/30/19 9:26 p.m.

Read the steps, agree it sounds pretty easy overall, but I don't think it adds any real value to the car to make it worth the time and expense unless I was keeping the car for myself. So I'll get it ready to sell and sell the hard top separately. Look for this in the "for sale" section later this winter if anyone needs an excellent silver hard top and is dying for an automatic :-)

kevinatfms GRM+ Memberand Reader
12/31/19 6:49 a.m.

Automatic Exocet?

AWSX1686 GRM+ Memberand UltraDork
12/31/19 10:20 p.m.

Sell to me for extra cheap? ;p

dherr HalfDork
1/7/20 3:45 p.m.

So was driving the NA around this morning and since I am going to do 2-3 cars per year for fun anyway this year, when I start doing the math in my head, it get's harder to sell this one for cheap when it is a great basis for something fun. I only intend to do fun cars (like the V6 MR2 project I just purchased), so build, play with them and sell to fund the next project as  a side business for 2020.

So back to the math. We purchased the car and hardtop for $3,000 two years ago. If I take the most rational approach, I sell the hardtop separately (minimum of $1200 as it is in perfect condition). Automatic NA Miatas with 140K miles on them are pretty inexpensive, so I figure I would be lucky to get $2K for it, given it needs paint, dent removal and a general refubishment of the suspension, brakes, tires, wheels, etc.

So is selling the car "as is" for $1.5K or so for a rust free Miata worth it, or should this be the basis for another project? I hate to just dump it and then be looking for one next year that is rust free next year. I am thinking Kswap or JV6. I am leaning towards a JV6 due to pricing of both the engine and kit. So running through the math, does this make any sense and can I sell it for what I will have in it? If I end up keeping it, then no worries about overspending but trying in 2020 to build some cars for fun and small profit.

Option 1

$3,950 for the jV6 Kit (http://www.superfastminis.com/store/p_982283/jv6-miata-package)
$500 for an Acura j32 V6 
$250 for a used Miata 5 speed
$1,500 for good used suspension, lsd diff and misc parts (or just find a parts car with wheels, suspension, 5 speed and LSD but a blown engine is probably the best choice)
$1,000 for a respray (I do the prep work and have a buddy spray it same color)

So do I invest $7,200 to make this a really fun car  and then if I sell it, do you all think it could be sold for what we have in it? 

2nd option is to just convert to a 1.8 and 5 speed, which could be done much cheaper using a running, but rusty parts car.

$1,500 Running parts car  (probably much less but looking for one with suspension upgrades as well as a 1.8 and 5 speed and decent wheels to minimize the $$$)
$1,000 for a respray (I do the prep work and have a buddy spray it same color)

So forgetting the labor costs (me), worth the effort to end up with a rust free, NA converted to a 1.8 and would it be worth $5k or more to make it worth my efforts?




pointofdeparture UltimaDork
1/7/20 3:55 p.m.

I don't think you would make your money back with the J32 swap. That is a somewhat niche build. Plus, whenever I see a project like that up for sale shortly after it was built, I always ask "hmm, what about this project was a failure that means the owner is selling shortly after finishing?"

You would probably break even with the 1.8 swap, but 1.8 manual cars are not particularly hard to find so that could be a loser as well.

I think the best option really is to just sell the car and hardtop separately as-is, unless you are really super jazzed to build a J32 car and willing to take a loss on it.

dherr HalfDork
1/7/20 4:20 p.m.

I do tend to agree, have not been able to find any examples of values for a J32 Miata unlike other swaps like K-series X1/9s  and MR2's which I have seen change hands for decent money. Of course the Flying Miata V8 cars have a resale history, but are a much deeper investment, I don't want to go through all the labor on the 1.8 swap just for the time, so we will need to decide on the car's future. 

jharry3 GRM+ Memberand HalfDork
1/7/20 4:32 p.m.
thatsnowinnebago said:

Sell it and the hardtop separately, then use that money and buy what you really want. Unless you really want a swapped Miata, in which case you've probably got a good candidate. 

This ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

bmw88rider GRM+ Memberand UltraDork
1/7/20 8:58 p.m.

J32 swap is really a niche swap so I wouldn't count on that for any resale value. You would probably get more with a K24 swap but even then who knows. Sell it off and move on unless you really really want a V6 miata. 

AWSX1686 GRM+ Memberand UltraDork
1/8/20 9:26 a.m.
dherr said:

$250 for a used Miata 5 speed

NA/NB 5 speed should not cost you more than $100. My miata parts source has an overflow of them and I believe said he'd sell to me for $75. 

AWSX1686 GRM+ Memberand UltraDork
1/8/20 9:28 a.m.

As for the J32 swap, I think you'd be hard pressed to make your money back, but that shouldn't necessarily stop you. If you want to get creative on cheap swap parts, I have some ideas...

As for swapping to a 1.8 manual, clean NA Miatas are going up in price. 5k for a good example is not out of the question. I could also talk to my Miata parts source for you on that one. Might be able to get you under $1000 for parts, downside is, no shell leftover to try and part out. 

dherr HalfDork
1/8/20 2:54 p.m.

Yeah, we should talk sometime soon. I am looking at several parts cars, that would give me all the parts needed including an lsd, trans and engine and lots of parts to resell. Pricing is below 1K, so my estimates are kind of high, but was trying to be realistic. J32 swap or K swaps are cool, but not really going to recoup the costs. If building for my personal use only, I would not care, but to buy and sell 3 cars a year, I want to try to keep my costs inline for any cars I intend to resell in the near future.

AWSX1686 GRM+ Memberand UltraDork
1/13/20 10:55 a.m.

Makes sense. Just let me know sometime you're working from home and we can catch lunch one day. I've been toying with the idea of a budget K swap for mine after I finish the 1.3 swap. I think I could do the swap for less that $1500 fairly nicely. 

wlkelley3 UltraDork
1/15/20 9:07 p.m.

Thought about turbo or supercharge and a Paco lift kit. SWMBO saw a Paco lifted Miata and thought it was neat but she refuses to learn to drive a manual. Know a guy that has a hard time with clutches from injuries and liked Miata handling but didn't like gutless Miata automatics so he supercharged his with a Jackson Racing kit. Gave him the power he wanted. 

An idea.

dherr HalfDork
1/16/20 7:11 a.m.

So my plans have changed as two 1.8 Miata M-Editions came into my driveway this past week. Both were non-runners, one a minor front end corner hit, the other a rough but complete example. I figured for $1,000 for the pair I could not go wrong since they both have the Torsen LSD rear. Well the car that was hit, appeared to be in really decent shape, and I had it running in about 30 minutes. Driveline appears to be in great shape, so I will likely swap the front/rear subframes and the transmission/engine into our 91 NA to gain the larger engine, manual transmission and LSD rear as well as what looks like decent suspension and the larger brakes. I will also be taking the interior from both cars and making one nice M-Edition interor for the car and then part out the rest. So after parting out both cars, this swap and upgrade should cost very little beyond maintenance items and my time.

dherr (Forum Supporter)
dherr (Forum Supporter) Dork
4/25/20 7:54 a.m.

Paging Keith.....

So earlier you had said that swapping a 1.6 car to an manual was a piece of cake, almost as easy as replacing a clutch. You also said to ignore any references to switching to the manual transmission car's wiring harness as it is not worth the effort. So I have all the parts from a 1996 NA M-Edition car that I am swapping to the 1991, including 1.8 engine, transmission and the entire torsen rear subframe. I'll also be bringing over the front brakes to get the brackets for the larger rotors.  I'll be purchasing the kit from Flying Miata for the 1.6 to 1.8 conversion to get all the parts to make the engine upgrade easier.

So the FM instruction hints say that you retain the mechanical 1.8 items, but keep the 1. 6 electronics. So do I need to find a 1.6 manual transmission ECU? I assume this will plug into the automatic's wiring harness and I just have to make the changes in the wiring to accomodate the backup lights, etc?

1 2
Our Preferred Partners