LocostUSA.com

I think to keep the outside looking like a mazda porter pickup and still have decent interior space (for a kei) you will need to use a shaft drive vee and build a 2x2 perimeter frame to mount everything to and provide a little more ground clearance versus bonnet/hood to the engine plus set back to allow the radiator to fit behind the grill, along with opening up the tunnel a bit on the left/passenger side all the way back.

A pic to add some idea to the scale of the problem for everybody else to ponder. I would not cut it up either. Since yours is a pickup, a little more ground clearance is usually a good thing.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

For less headaches, I’m suggesting no larger than a 750 shaft drive and 89-97 ford ranger ifs (short/long arm) with a standard coilover attached at the original strut tower with an adapter. The kei crossmember and ford arms will need to be redesigned but the spindles and balljoints can remain stock ranger. I suggest cutting the ford arms to fit tubular arms that are offset enough to overlap and run the full width of the chassis for reasonable camber gain. The radius arms can be fitted with sphericals. It is way over built for a kei as-is but it can be improved and wheels as small as 13 inches can be fitted. 89-97 have inverted joints that are easier to adjust and have a pinch bolt at the top.

Modifying the original suspension is another option. Newer readily available components can be adapted. If you want to go this route, reassemble the suspension and take pics from various angles.

To keep the rear simple, and so you can keep the truck bed, instead of an irs, the rear axle should be swapped for a ford 7.5 with 2.73 gears from an ‘80s tbird, mustang, cougar, capri, etc then narrow the housing as needed and you get to keep the truck bed. The ranger never had 2.73 to my knowledge but the housing is essentially the same except for leafs versus coil springs. You can have the axle shafts shortened and resplined to match the housing or buy new custom length axles from several companies. A torque link/traction aid will be needed to control pinion angle with what you have now. The easiest way to do it is with alteration of off the shelf traction bars/links. A safety hoop for the driveshaft near the front is a good idea. Make sure there is a slip yoke on the driveshaft for the diff movement.

A full width miata suspension will have extremely wide flares all around and be a lot more work and cutting.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

https://motor-car.net/mazda/item/11431- ... en-1961-68

https://www.youtube.com/watch?v=2b-aI0f2tJ0

https://www.youtube.com/watch?v=vCT0yUEY7Os

A nice view of the suspension: https://www.youtube.com/watch?v=2jfiOAmm9W8

The ’73 two stroke version with 35hp (versus the 20hp four stroke.) I wonder if it uses the same transmission: https://www.youtube.com/watch?v=MYnBExcWdHs

Another option is to adapt a briggs vanguard twin four stroke with about 30hp to your original transmission by adding a bell adapter, flywheel the same thickness of the original plus the bell adapter thickness, using original clutch, pressure plate, pilot bearing, etc. Lots more torque and displacement, air cooled, and an axle swap appropriate to the vanguard rev limits and desired speed. I’ve seen a lot of these used on cushmans.

EDIT: after researching the vanguards, they all have small splined or tapered shafts that wouldn't do well with a flywheel to engage a clutch imho. A kubota 1105cc 3cyl diesel is another option that is about 19 inches long overall and comes with a traditional flywheel flanged crank and about 30hp but may be too much torque for the original trans. Commonly used on refrigeration units for 18 wheelers.

The suspension improvements could be practically bolt-on.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

If you check the literature for the 33 hp v-twin, https://www.vanguardpower.com/na/en_us/product-catalog/engines/big-block-vtwin-horizontal-shaft/vanguard--330-gross-hp-efi.html there are options: Straight Keyed (1-1/8" & 1-7/16" Diameters) Tapered (SAE 2.25"/12" & 10:1)
I believe that the Taper is for a generator application. Not sure what standard config is.
Waltj

I’m talking about using the original clutch system. I’m sure the vanguard crank engagement is fine for hydraulic pumps, centrifugal clutches, or anything where the operator cannot spike load by suddenly engaging full power in the wrong gear.

A 40 hp beetle has four dowels on about a 1.750 circle and a single, large center bolt (called a “gland nut”) torqued to 217 ft lbs which is ok if not abused with up to around 60 hp in a light beetle. If it gets lose, the crank and flywheel are usually ruined. Efforts to improve this weak link include wedge matting the crank to the wheel by machining tapers, drilling for eight hardened dowels, a much larger washer to fully cover the dowels, a special bolt torqued to over 350 ft lbs and red Loctite.

I like the vanguard taper for engagement and concentricity but the length adds to the overall length needed to clear the trans input shaft, the end bolt is much too small for adequate torque, and they are no dowels or keys.

For the vanguard keyed output, I don’t think a single key way and small center bolt torque capacity is going to be adequate to manage what would probably be an 8 inch by one inch thick clutch friction plate and three finger pressure plate.

A fellow made a series of videos on youtube fitting a smaller briggs in a stripped down, early model honda insight using a centrifugal clutch, cvt, and the original insight 5 spd. Unfortunately, the porter does not have room for a cvt or the offset it would create to clear the existing tunnel and to my knowledge, no off the shelf cvt exists with enough torque capacity for the vanguard output but that could change. I will provide a link to the vids.

The first one. Imho, it would have been nice to start with a HMV Freeway rather than a honda insight:
https://www.youtube.com/watch?v=cL2FKDt ... 0s&index=3


One could go hydrostatic with a pump/motor combo on the vanguard in the engine bay and a long driveshaft instead of mounting the hyd motor directly to the diff so it would suffer the abuse of being unsprung weight. Also not very efficient compared to direct drive but it could solve the reverse problem.

It’s hard to beat a bike motor with integral trans for something like this, even with alternator limits and potential oiling issues when replacement parts for the car and trans are probably non-existent.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Thank you for the response. I learned a bit there. I think I misunderstood the "splined shaft".
Waltj

Sorry for the slow reply Miatav8,MstrASE,A&P,F I do appreciate the information you have given. I have had some more free time recently to tackle the fitment problem, two things I recently saw that gave me a bit of inspiration was a zcar with the tube front end with ifs and a fsae car. the width of the fsae is pretty close to the truck so that really struck me. This is a really fast model of how fsae suspension components would look with the hayabusa upfront. I am currently working on replacing some of the fsae components with the miata stuff I have like the upright which are surprisingly similar in size.
1.

2.

3.

4.

5. I had some more free time in the evening to add some of the Miata parts. The wheel is 13x8, lower control arm kit comes from kineticvehicles I have their upper control arm kit too, I just haven't modeled it yet which is why it currently has a stock Miata upper control arm.

double post

No need to double post.

I'm confused about the purpose. Are you building a race car or are you trying to repower a kei for practical use? I thought you were trying to keep it looking original on the outside (i.e. no extreme fender flares) or maybe the scale is not adjusted yet. Look at ccrunners miata/bec based berkley to see how short the arms would have to be.

Wheels and tires small enough to fit those fender openings probably won't clear a 90-93 NA miata caliper.
You probably realize the need for a tube frame, cutting out everything forward of the firewall, hanging the front clip on tabs welded to the tubes.

I still see the rack placement as the #1 issue. The tie rods and rack should be on the same axis or the rack closer to the front axle than the tie rod bosses on the spindles. I spy reverse/negative ackerman where the inside tire scrubs when turning.

The coilover bellcranks would need to be turned 90 degrees and dropped below the hood line which is very close to the top of the engine, but like you said, a quick rendering.

If you are trying to make an old kei practical, I see bikes that are around 10 years old with the 1100 vee engines dirt cheap on fb and craigs but the busa in this has too many compromises if you want to preserve the qualities of the kei. ATV suspension, brakes, and driveline would be a better match than any modern car suspension.

If you were building a tube frame car to fit the footprint, like a legends/dwarf racer that use large bike engines like the busa with an offset 70-80s small toyota axle, it would still require a lot of butchering and thin metal is more tedious to weld, even for an experienced welder. Consider the time involved. Time is more important than money. Do you want to drive it in the next decade or tinker? Nothing wrong with either option. I want to watch the build either way.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

The double post was accidental.

I am doing both, I want to repower a kei car that has parts that are non-existent and have something I can take to a track and have some fun in. I actually don't mind fenders, the idea is to keep it looking like a kei truck and fenders won't take from that and eventually I do plan to add a roll cage just because it worries me driving such a relatively small car next to cars that are 4 time my size. The scale is 1 to 1 all measurements for the lower arm were taken by me and the engine size was referenced with my Hayabusa engine. I can take a screenshot of the dimension of the arm with a stock Miata arm so you can get an idea of its size.

My current tires are on 13x8 rims, the stock tire of the truck is 10x4.5 if I remember right. The 13-inch rim does clear the Miata caliper with no problem. The overall outside size difference between the stock tire and rim combo and this new 13-inch combo is 4 cm(I can take a photo of them side by side if a visual comparison is preferred)
1.

2.

3.

Yeap I realized I need a tube frame I don't mind that if anything I like the idea of being able to remove the entire front end when I want to work on it.

The rack replacement I am still working on it, have considered using a steering box setup or maybe using a similar steering setup to what they used in this car. https://bangshift.com/bangshiftapex/finish-a-zx-14-powered-1972-honda-z600/

I want to drive it for the next 2 decades and also tinker with it. I just don't want to start the cutting without thinking it completely thru.

Edit:
Below is a size comparison of the kineticvehicles lower arm and the stock Miata arm

Ok, basically a tube frame race car. Cut out the firewall and move the engine back about 12 inches for a rack in the normal miata fore-aft position but narrowed or use a buggy rack with the right width between inner balls for the suspension inner balls to minimize bump steer. You can use a rear steer RHD rack on the front but flipped so the pinion is on the correct side. Make the firewall removable by having a flange matting surface around the edge for engine access.

You might render or position the wheels to where the track will be with your plan, then run strips of masking tape or cardboard to see how it will look with the flares if you decide to mod the fenders, since the fender lip will probably hit the tire with any suspension movement.

I am familiar with miata suspension dimensions and I know the early NAs came with 13 inch rims. Since you have 8 inch rims, I'm guessing the scrub radius is not a concern.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Wow wow there i am hoping to leave the firewall in place, that's why i have been jumping thru so many hoops. Plus moving the engine back 12 inches is not possible that would put the engine around the dashboard. There have been a couple of mini that have had a similar setup with hayabausa engine up front powering the rear wheel that I am using as inspiration for the build here is one http://davidsclassiccars.com/mini/2125-1979-mini-hayabusa-1300-turbo-rwd.html
With the new track width, 3-inch fender flares would be required which won't look bad in my personal opinion.
Below is how a stock Miata steer rock flipped and with it rod shorten to accommodate the smaller width.

Here it is with the engine raised by 5mm and with the connecting tube moved inward

You have the option for a period of time to delete new posts. It is easier to delete than typing "double post".Just fyi.

Fwd strut type spindles so the steering arm can be fitted to the adapter or custom spindles where the outer steering ball is close to the same height as the ubj, allowing the rack width (inner ball to ball) to be wider without bumpsteer and better access to the racks pinion, which may need to be center tapped for adequate travel/turning circle.

Another option is to use an offset pinion fwd rear steer rack, depowered and flipped, with a bolt-on plate to which the inner balls attach, so the width is whatever you need by fabbing the plate. There are buggy racks that do the same thing but they have a centered pinion, making the intermediate shaft routing a little more difficult but doable.

That still does not fix the rack fore-aft location. I said about 12 inches because I don't know exactly how much set back is needed. Looking at your latest big pics, it appears you only need about 3 inches. The firewall cutout would be less of an issue for the driver than the passenger side and you could split the required distance between setback and moving the axle forward an inch or two. It appears from your pics that all of the cutout would be from the hood latch area to the passenger side fender with no firewall mods to the drivers side.
If modifying/fabbing steering arms, they could be longer with a quick rack or ratio adjustment at the column with a chain and sprocket box (also helpful to offset the intermediate shaft if needed to reduce joint angles) or a compact gear to gear ratio changer. Your still limited to balancing bumpsteer with inner ball location and rack travel/turning circle.

In a nut shell;
1) I'd cut the pax side firewall 3 inches and all the foreward inner fender area out for tube framing that will run the length of the car and tie into the unibody the full length with some plates and gusseting.
2) Move the ifs axle cl forward 2 inches for some ackerman and extra clearance.
3) Shorten the miata uca an inch so the engine can be offset to the pax side, putting the ucap very close to the head to reduce the firewall cut and improve rack pinion clearance for more travel and reduce joint angles.
4) If using miata ifs, drill the tapers and add a couple inches of spacer to mount the rack as high as practical.
5) Use a center tapped rack new for a buggy with a centered pinion or depowered oem fwd flipped. Make the plate the right width for the height.
6) Lower the engine and/or tweak the wheelbase if needed for the high mount rack.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Forgot to mention the track versus flare. The track spec listed for a vehicle is the distance between the centers of the original tires and rims. If the flares are going to have a close fit to the side walls, they need to stick out past the tire an inch or so for bump clearance and for when the steering is turned and the car rolls or experiences bumps. Take the track, add the oem tire tread width (versus the bulge width) plus the fender clearance for each side (1x2), then add how much further the 13x8 rims and tires stick out x2 for the flare width. I'm guessing the flares would be about a foot wide. I didn't do the math; just speaking in general.

You can shorten the control arms equally with some reduction in travel and bring the lcaps and ucaps as close to the engine as possible to reduce the flare width along with original miata 13 inch wheels and a slightly smaller od such as 155-70-13 or similar. Just an idea if you want more of a sleeper.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I get a feeling you don't really read my post, considering I have posted that I don't want to cut the firewall unless it is absolutely needed and considering I am not in a hurry to finish it I have time to see all the options and yet it is still suggested.
I don't see the point of suggesting fwd strut maybe I am missing something, I have seen cars with racks at a much worse angle than what my cad shows heck I've seen race car with racks at worse angles too.
In my photo no part of the firewall has been cut the only thing that has been cut was a shelf that functions as a mount for the spare tire and a tunnel for the air into the cabin.
As for the track width, I have mentioned already that it is only around a 3-inch increase on both sides so I have no idea where you are getting a foot?
If anything my biggest problem is not the width or the steering rack it is the propshaft and the angle at which it will be at. Nonetheless, I appreciate any input someone has on the project because multiple people tackling a project is better than one. Below are some photos of how it would look if the steering was reversed to behind the engine one of my friends asked me how it would look if it was set up like this.
1.

2.