dmk0210

I've done a lot of car work. I've done engine replacements / bolt in engine swaps, I've rebuilt a transfer case, complete suspension bushing and spring rebuilds, basically all the mechanical stuff. My education is in electronics and computers, so wiring and electronics are no problem. However, I can't weld. I do know a guy in the next town that I could take an assembly to and have him weld it at his shop, but he's not going to come to my garage and get under my car to do it.

So I've been looking at Martin's Monster Miata kit for the 302 and watched Stacy David's Banshee project. It looks like the whole kit is bolt-on with the only welding required for the be the rear diff mounting.

What about a Getrag or 8.8 rear? Does the V8 Roadster kit require welding? Are there any bolt-in kits for the diff?

Is there any other welding that I've missed? I don't want to start a project and then get stuck halfway through because something needs to be fabbed to the chassis itself.

acedeuce802

Getrag and 8.8 both need welding brackets on. The Getrag is very simple, the rear of the diff is mounted with a bolt-on bracket, then there are two little tabs that get welded for the front snout. The rear subframe would be easy to take to someone to have them weld it.

I'll let someone else comment on the Ford swaps as I don't have experience there, but all LSx swaps require welding in the engine bay. The V8roadsters is the most intrusive because you have to widen the transmission tunnel (though I've read that some have gotten the tunnel wide enough with a BFH). All kits require cutting out the gussets in the rear corners of the bay and welding support plates in their place. If you're interested, look up the Flyin' Miata V8 Instructions for more info on this.

dmk0210

Well that's definitely doable then. Thanks! I guess the real trick there is making sure the alignment is right when they do get welded.

As far as I can tell, the Ford swap just requires two clearance cuts and cosmetic plates welded on over those, but it looks like those could be pop riveted or bonded on.

acedeuce802

You can mount the engine/trans first, take an angle measurement of the engine/trans, then take an angle measurement of a flat face on the rear subframe (or where the subframe mounts in the chassis when it's uninstalled). Then you'll know the diff pinion angle relative to the subframe mounting face.

Ford5.0

I did the Ford swap using Martin's kit and a 7.5 diff. I mounted the engine/trans first and got an angle measurement. Then I temporarily hung the diff from the subframe using the rear bracket supplied with the kit. I bolted the front bracket to the diff with a few washers in between. I then set the pinion angle and marked the location of the front bracket on the subframe for welding. Then I removed the diff and the subframe and welded the bracket onto it. Once reinstalled, you can fine tune the pinion angle if necessary - I ended up removing a couple of washers to get mine perfect. You could take the subframe to a shop for the welding.
You may want to consider purchasing a mig welder, especially if you can find someone that can weld and would be willing to make a house call - that's what I did. That way you get a new tool (win) and you can a learn a new skill. After a fair amount practicing, I was able to make the exhaust myself.

dmk0210

Thanks guys!

preluding

I'm doing my LS swap and don't own a welder. I'm now almost complete (haha, it'll never really be done). I paid a friend to come in with his 110v welder and no gas to button back up the sheet metal around the tunnel and weld in reinforcements. I'll get him to come back shortly to weld in the diff bracket as well. Aside from those areas, that is really the only welding that I've needed to do and it can be accomplished quite easily as the welding part of it doesn't take very long.

I've been working on this on/off for over 2 years now. I'm mechanically inclined but this has been a massive learning experience as my initial timeline involved around 6 months.

If you're flexible with time and resources, go for it.

dmk0210

Thanks for the insight preluding.

I do intend to take a few years to enjoy working the project, be detail oriented and do everything right. The first step is finding that perfect car with a clean, rust free body and under $5k. That might take a few years in itself. I have some very specific things I'm looking for.

This one is more about the journey, than the destination.

BGordon

Here you go.
Looks like an excellent candidate for a V8 swap.
Price is right.
https://www.v8miata.net/cars-sale-4/...e-roller-3305/

Serenity

With such a small amount of welding needed and kits galore for part sourcing, should I really expect to be paying more than $30k for a shop to do. Like I have the car already. So get my minset across, here is my car. Good condition structurally. And a cheque for $30k. I expect body and interior to be left as is (obviously r&r for building reasons but no new parts.). Car done. Thats 16,800 in parts (using numbers from discussions with V8roadsters) and $13200 in labor? Is that not enough?

Edit: for reference this is an 06 miata, which from what I hear is the easiest of the miatas to LS swap.

Ticopowell

I'm new to v8 miatas, but that price seems fairly cheap. If they are charging $100 per hour, that's 132 hours of work. I've heard these take 200-500 hours of work to build, depending on the car, motor, tranny, diff, and other options you install.
If I'm paying a shop to build me a car, I don't want the cheap mechanic working on it, so $150 an hour doesn't seem unreasonable. $13200 is 88 hours of work at that rate, which means 2ish weeks of work on my car and I don't think any shop would do it that quick.
That's why I'm planning on building my own, my labor is free (according to my wife) and we can't afford the $50k a shop charges to convert a car, so that mattress it an easy choice. I hope to learn how to weld, I have some space to build, and since she won't let me build a cobra (again, can't afford the $50k, plus she wants a roof and an hvac) that leaves us with building a V8 miata.

I hope that helps!

djwarner

You don't say if you own a Miata currently. You might want to consider an NC that has more room in the engine bay. I swapped in an LFX with a V8Roadster kit. Only welding was for tabs for the diff mounted on the rear subframe. Sent the subframe out for that.

My LFX puts 320 HP at the rear wheel after a tune. Managed to keep the PS, PB, AC, ABS, full dash and cruise control. If you are looking for a track only, this won't be important. But if you will daily drive it, you will appreciate the additional goodies.

Serenity

V8roadsters build using a brand new motor is starts at $38k. And if they do the work you know you are paying a premium for the name (rightfully so). But at the same time a smaller custom shop will have techs just as good. But minus the premium. 2wks billable time is less than 200hrs (no1 works 24/7) so stretch that out it become a month if I am the only car they work on for 12hrs per day, which is unrealistic. And I may be wrong on this but I seem to remember 200-500hrs was for an at home builder on the NA body, which requires the most cutting and welding. And to the $50k build I assume that gets into interior and at least a little body work, of which I am not including at this time.

djwarner

A quick note about the V8Roadsters instructions for welding the rear subframe.

The rear subframe and all its attaching parts are bolt-ons. Once removed from the chassis and suspension parts taken off, the subframe can be easily transported to a weld facility in a sedan, suv, or pickup truck. The instructions provided are explicit and easy to do.

All in all, it is not a go/no go issue.