1992 Mazda Miata V6 Swap- Build Thread

Harvey wrote: Why do I get the feeling that this swap is overall more awesome than a V8 swap?

LOL I don't know if I would go that far... Maybe overall more sensible than a V8 swap? There was an FM built LS3 Miata in my driveway a few days ago and that was a pretty awesome swap. I didn't have time to get a test drive from him, but I will be hitting him up soon.

This swap makes more use of the parts that come with the car, the LS swaps are more comprehensive in upgrading the entire drivetrain - thus the greater amount of work and expense. Which is more awesome depends on your sensibilities. I'm looking forward to seeing a well executed one of these in person.

Can someone educate me on why there are no mounting points on the engine? Would it be due to a lack of engine mount bosses on the block or is it a exhaust clearance thing? Maybe they just think its an elegant solution? Seems to work in just about every piston airplane install I have seen.

The reason I want this to work is because I think it would be a great addition to the MGB engine swap options. A Miata gearbox and a Honda engine would be great. Remains to be seen if it would fit under the hood.

The other option is the LFX as installed in the Miata by V8roadsters. Still waiting to hear from anyone who has tamed the electronics on either of these V6 swaps. For some reason that subject is glossed over by both companies even though it is the one that scares most potential swappers.

Not sure why there aren't engine mounts. There's bosses in the block that work.

NOHOME wrote: The other option is the LFX as installed in the Miata by V8roadsters. Still waiting to hear from anyone who has tamed the electronics on either of these V6 swaps. For some reason that subject is glossed over by both companies even though it is the one that scares most potential swappers.

Both of these swaps are still pretty new and haven't seen many installs. A total of one for the LFX, I think. With the V8R swap, it'll be left up to the customers to address some of the finishing details. In both cases, it'll take some time for the information to get out there.

Mounting points: I can't speak for the designers as to why they choose the design they did. Personally I do think it is clean/elegant, it does make exhaust routing easier, and while not common, it has been proven an acceptable solution in other implementations. Before making my purchase, I thought about how I could address it if it became a greater concern. After seeing how stable the engine looks in their dyno run video (my supercharged 1.6 bucked a lot on the dyno in comparison) I am less concerned, but I still have my remediation plan in my back pocket if needed.

Wiring- For the J Series, Minitec is actively working with a few different partners that will provide you with choices of either: A) a jumper harness that will plug in to the Miata harness, Honda harness, and Honda (or AEM) ECU B) a service were you send the Honda/Acura harness in for thinning and re-working and get it back with a few wires hanging off that are labeled with instructions of what to do with them.

Currently there are successful installations using these items but are not ready to be offered off the shelf yet, as they are still working through the differences between the different Miata harnesses. As early adopters, they are working with us offline on this sort of thing and once it is bug free they will list it on their site much like they do for their Honda harnesses for classic Minis.

ECU- 3 of the currently running cars are using the AEM plug and play ECU, and there is 1 so far running on an Acura TL ECU with the immobilizer removed. Again, more information will be made public as more of us Beta testers complete our builds.

Now with that all said, lets get this thread focused back on my build. I will provide a lot of details on how I address Wiring and ECU once I get to that point.

Tonight the new oil pan was installed The first step was flip the engine upside down on the stand and to remove the old pan. I have heard some at a hard time separating the old pan from the block, but there are 2 slots made for a pry bar to fit in and it popped right off for me.

Here you can see the pan off. Notice the location of the oil pickup? That won't work with the new pan.

Before the new pan goes on, you need to remove the windage tray and stock oil pickup, and install the new pickup that comes with the kit.

This is what the inside of the new pan looks like. The pickup needs to slip into the sump, so it is good to practice before applying the liquid gasket.

The liquid gasket I used was Hondabond, as it is what Honda recommends. It calls for it to be spread thin over the mating surface of the block and it cures fast, so it was helpful to have 2 people.. one to place the bead and one to spread it thin. We were in a hurry, so no pics until the pan was in place. The front bolts under the sump are a real pain to get in.

Here is a blurry pic of the pan once torqued.

And here is a side view where you can see one of the easier to reach of the 4 front bolts.

Watching this with interest. I love the idea of an NA that would outrun my current Mustang while using a stock motor and stock ECU. It seems like the best of both worlds - the performance of a highly modded Otter with daily driver reliability.

There was no progress made over the weekend, as I had other commitments. Tonight I tackled the transmission adapter plate and flywheel. The adapter is first put in to position along with 2 included steel dowels. There are 4 included allen head bolts that go through the adapter plate in to engine. The holes in the adapter plate are counter-bored to allow the bolts to be flush with the adapter plate and not interfere with the transmission. There are also 2 included allen head bolts that come through flanges cast into the passenger side of the block and screw in to the adapter plate.

Adapter plate mounted and Flywheel adapter in place

There is an included flywheel adapter and bolts that moves the flywheel out from the engine to compensate for the thickness of the adapter plate. The included flywheel is a stock Honda B Series flywheel that has had the ring gear flipped to work with the starter. The start provided is designed for a 1984-1995 Honda Civic SOHC.

Flywheel and starter mounted

Keep the updates coming.

Can't wait to see the finished project.

Loving this build. If i ever get an NA i will most likely do this.

There couldn't be a easier time than now to replace the old clutch line. I picked up one of the extended length braided stainless steel ones from Treasure Coast Miata for only $30 shipped.

Got the old one out.

And the new one is in.

Time for some suspension work. The front subframe and suspension came off the car all together, so first I disassembled it and figured out what would be reused.

The shock assemblies looked pretty nasty.

A little cleaning made a big difference.

The control arms looked pretty dirty and had the original bushing and ball joints in them.

I cheated a little here, as I had a set of control arms off of a 96 parts cart that I had already cleaned and removed the bushings. I pushed new OEM bushings in, replaced the lower ball joints with new OEM ones, cleaned/repacked the upper ball joints and gave them new boots, and then reassembled everything on the new subframe with new alignment bolts.

Everything is now installed on the new sub-frame and ready for bolting in to the car. The lower control arm attaches to the new subframe just like the stock one, but the upper control arms are a little different. Note the zink plated washers on the upper control arms. The kit comes with 12 of them and 6 are used on each side. You can have them spread equally front to back for stock geometry, or you can split them unequally which I believe results in change in castor. Maybe someday I will play around with that, but for now I split them equally.

Love this thread and car...Seems like the perfect match...revvy V6 in a beautiful chassis.

zracre1 wrote: Love this thread and car...Seems like the perfect match...revvy V6 in a beautiful chassis.

Thanks!

Time for a little update... I good friend​ of mine was out Sunday evening to take car of the paint issues in the engine bay. He got it all prepped but then realized that a crucial can didn't make it into his box of supplies. This is how it sits now, patiently waiting for his return. ;)

I ordered a new Heater core for the car, but unfortunately it arrived damaged. I'm hoping the exchange process is not too painful.

I also got a set of new heater hose grommets. I didn't realize how bad the old ones really were until I pulled them out and put them next to the new ones.

I'd just braze that heater core with some plumbing solder and a torch.

beans wrote: I'd just braze that heater core with some plumbing solder and a torch.

I considered that, but it would mean I would also need to try and remove the new foam on it temporarily or risk melting it. I figured I would see if I can get it replaced with a good one at no cost to me first.

BTW, I had a look at the Superfast Mini car yesterday. It might be worth fabricating an impact bar in front of that oil pan while you've got the car apart. Just to avoid a potential bad day. On a normal Miata, the subframe takes the first impact. On these cars, the pan's a bit lower and leads the charge.

forgiveness if this has already been covered, doing anything to the rearend in terms of durability or just shenanigans?

Great build! But I do have a question about the oil pick up... (Picture please)

Is there a screen in there to keep debris out of the oil pump?

I know, why couldn't I ask that 20 days ago?

Keith Tanner wrote: BTW, I had a look at the Superfast Mini car yesterday. It might be worth fabricating an impact bar in front of that oil pan while you've got the car apart. Just to avoid a potential bad day. On a normal Miata, the subframe takes the first impact. On these cars, the pan's a bit lower and leads the charge.

I will be looking at ways to add protection for the oil pan and starter as I get further along.

Flight Service wrote: forgiveness if this has already been covered, doing anything to the rearend in terms of durability or just shenanigans?

I upgraded to a 1.8 torsen diff several years ago to handle the supercharger I had.

noddaz wrote: Great build! But I do have a question about the oil pick up... (Picture please) Is there a screen in there to keep debris out of the oil pump? I know, why couldn't I ask that 20 days ago?

There is a screen, The site shrinks the picture down, but if you right click on it and open image in a new window, you should be able to zoom in on it. It is not as obvious as the pic of the original pickup with the staining to add contrast, but it is there.

Hey awesome build man! A "J" in a miata sounds about perfect. I don't know if it would help any but I have a friend who makes parts parts for "Js". His site is prankparts.com. Well keep up the awesome work I'll be following this one.

NateE30 wrote: Hey awesome build man! A "J" in a miata sounds about perfect. I don't know if it would help any but I have a friend who makes parts parts for "Js". His site is prankparts.com. Well keep up the awesome work I'll be following this one.

Thanks... I actually already have one part that I ordered from him!