Tobiczyk

So once again, another LS Miata build underway. My story is not too atypical from most. Mid 30s. New family addition. Wife strongly urges to get rid of the motorcycles and maybe find another project. (Yes my wife said to get another project. That is one of the reason why I married her, she gets it)

Searching craigslist, facebook, etc. I came across a gentleman selling his 2000 Miata. Originally a 1.8 manual, he bought it with a bad motor and immediately dropped that and the trans, parting out what he could. Unfortunately, like many projects, that is about as far as he got. Some of the interior was stripped, but that was about it. He ended up needing to sell off projects due to moving or something.
Thanks to that, I was able to pick it up for a pretty good deal. The bonus was he had already started the engine build, which came with the car. So I also received a 4.8/5.3 Gen III block that had already been machined .020 over, 4.8 crank, and 862 heads. Great. (even got him to throw in the engine stand)

So here it sits. Day 1 of getting it home. Everything is there except the engine/trans, seats, and convertible top.

The shell is in fairly good shape. Random dent/scratch here and there but nothing that cant be bumped out. Little rust around the rear wheel wells but again, nothing that cant be fixed. It was an original white car and someone repainted it before. 20 footer single stage job. Could be worse but will need paint anyways so no big deal.

As I was saying, it came with a Gen III 4.8 engine but all disassembled. Since it is an iron block, im getting rid of it completely. Would be great for someone who wants a turbo build but its just too heavy in my opinion for such a small car and 100+ lbs on the nose will hurt it in every way.


With all that said, I am selling it if anyone is interested.....

So, that leaves me with planning out the build from where it is......
For starters, I need to repair the body and repaint. The wheel well rust isnt major but significant enough to justify cutting it out which leads me to probably replacing the driver quarter panel and maybe the passenger (used to work in auto collision so no worries there). The rest of the shell is fantastic rust wise, just the random dent that will be pulled/bumped when i get it ready for paint. Have not decided on what color. Have a while until I need to make that decision so we shall see.
The suspension is VERY rusty. Im actually amazed at how bad it is considering the body is 99% good. I have scoped inside the rails and they are good as well. I was able to already pick up a new rear cradle at a u-pull-it near me. The front will obviously be replaced for the new engine anyways (probably just going v8roadsters cradle, too simple to pass over). That would just leave the control arms to replace. Luckily I also have a guy who lives near me who parts out and sells NB miatas left and right. Can get good replacement ones to start or just upgrade to some adjustable control arms. Will decide when I get to that point.

As I mentioned probably going to use the v8roadsters cradle. It is already designed perfectly to handle the task and for the price you cant beat it. Sure it would be cheaper to build one but materials and labor add up and my time is money. Rather just buy a part that I know is exact than bother with designing and building one. If you prefer to build your, bravo to you. With the cradle going to get the frame rails as well. But I will not be getting the cross member or any of the other cradle components. Reason being is the transmission....


I will be using the 5 speed from a Z32 300zx TT. In all my research in looking at possible transmission options I just could not justify the cost of a T56. I know it is a great trans for the project, it works, shifter lines up perfectly. BUT it is soooo expensive. I have been looking for 2 months and the cheapest I have found is 1500 for one that needs a full rebuild 2500+ for a used one that i know nothing about. That is very hard to justify. Plus add on the bell housing, shifter, clutch setup, etc. You are looking 3500+ easy. Instead I will be able to use the 300zx transmission for a total cost of about 2k and if it ever does go bad, i can get another one for sub 500. Which it shouldn't. These are known to handle 700+hp all day. Honestly, you just cant beat it. Good news for me, I was able to find one used for $300 with a starter (you use a 300zx starter on it). Obviously to make it work I will need an adapter so LOJ will be the source there. Their adapter kit is a bit pricier than the G-force kit but it works on both the NA and TT. The real selling point for me is the rebuildable flywheel that allows you to replace the friction surface and again, that is much cheaper than having to replace an entire flywheel (if I ever needed). Because of the length of it being a bit longer than the T56, I will have to shorten the shifter location dramatically and possibly use slider plates for the engine but initial math and I think it can be done. With the gear ratios of that transmission it lead me to wanting something in the 3.00-3.30 final drive ratio. Enter the rear end....



I was able to find the perfect option (even if it will require a bit extra work). All 2015+ automatic mustangs came with a limited slip 3.15 super 8.8 (i believe there was an option 3.31 as well). If you are not familiar, the super 8.8 is basically the next generation of ford 8.8, similar to what is in the tbirds, some mustangs, mark VIIIs, etc. It maintains the same 8.8 ring gear but with a much beefier pinion, housing, etc. This is the aluminum version which under HIGH hp are known to break off the ears but I am keeping it relatively mild. If they do ever break, it is easy to source the iron case as well and replace. The mounting points are different than the standard 8.8 but still reasonably located that it should not be too difficult to fab up mounts for it. With the 3.15 ratio, 1st gear with top about 40mph, 2nd 70mph, 3rd, about 100. And the best part, cruising at 80 at about 2800rpm. For me, that all sounds perfect but to drive this i will need a new engine....





Since I am getting rid of the iron block I was forced to get a new engine. I was able to find a used LH6 for $400 (2009-2011 all aluminum 5.3 with AFM and VVT). I got it from a mechanic who pulled it from a customers car to replace with a used engine. Reason it was pulled was simply a bad lifter (very common with the AFM junk). For the customer it would have been 2200 in parts and labor vs 2500 for a used warrantied engine. I don't blame them for the choice. The guy paid for the core himself in plans to use it for something and just never did (he actually had multiple engines for the same reason).

***Side note*** For years I would watch all the shows, Roadkill, Hot Rod Garage, PowerNation, Trucks, etc. and never believed the old adage "we picked this up from the junk yard for $250. Heh, i guess you really can get lucky sometimes.

I plan on doing some mild work to the engine. I found an LS3 cam locally that was brand new (pulled from a crate engine before being installed) with the 4x gear. Have LS6 springs on the way as well. I plan on keeping the bottom end stock. Everything spins great and I dont see a reason to open it up until I actually need to. Came with 799 heads so I will just disassemble the heads and have them sent off to be cleaned up, maybe a little porting, upgrade the springs, good to go. Also since I am already replacing the cam, its an good time to replace the cover and remove the VVT as well as replace all the lifters and valley tray to remove the AFM. All said and done should be 400+hp no problem.

For now, there we have it. I do not have a set timeline on this one. Not working on it every night and weekend but I also don't want it to take forever. I think a year is a conservative timeline. Biggest thing now is starting the engine build and getting the rest of the parts (cradle, engine management) and getting the body fixed/ready for paint.

If anyone has any questions or insight that I should know, please throw it my way. I will never claim to know everything and will trial and error until I know a better way. Thanks

BGordon

Good start.
It is nice to hear that you are going with the V8 Roadster subframe as it gives better access to some tight places over modifying the Miata subframe.
Based on what you currently have you should be in for many months of enjoyment and work and frustration to get the car road worthy.

Tobiczyk

The work and frustration is 90% of the enjoyment.

Let's be honest, most projects start with a "perfect plan". You start buying parts, building, cutting, grinding, etc, then realize half the parts you bought arent going to work because of a single little minor reason that you blow up in your mind to be huge. You buy new parts, build new brackets, cut everything out you had and start over......only to get back where you began and realize your original plan was better and revert back to that wasting both the original work and secondary work to go back to the beginning. Then in your frustration and life getting in the way you walk away from the project for 2 years and when you come back it, you already forgot the plan and once again have to start over. Parts are missing because you had to move in the middle of it and have no idea where the box with all the electrical went.....which I think is exactly where this was when i got it. Hopefully I dont follow that roadmap.

pj_mcgarvey

Sounds like you are off to a great start with the transmission choice. I didn't really know these trans were an option back when I did my swap, and if based on my experience with the T56, I'd like to switch it up a bit.

On the subframe, I'd recommend the V8Roadsters frame as you mentioned, but I'd be curious about the much cheaper subframe option that doesn't include the engine mount standoffs. If you can fab and weld, then this could save you over $1000.

Looking forward to seeing a fresh build develop here. Good luck.

pj_mcgarvey

One add'l thing is the diff you are using. I'd be curious how much taller that one is from the axle up, as I have less than an inch of clearance from the top of my aluminum Cobra 8.8 to the bottom of the gas tank heat shield. May all depend on your mounts and pinion angle, but just something to be aware of.

Tobiczyk

Yeah. I have not fully measured or laid out the diff onto the cradle yet to see how we will be sitting. I want to get the engine/trans in first, get pinion angle matched up. That may determine exactly how/where the diff is mounted. It doesnt appear to be much taller than the 8.8 IRS in the Tbirds (I have owned MANY supercoupes so im going off of memory here). When I get it measured up I can throw the dimensions on here for reference.

I already reached out to v8roadsters and I can get the cradle by itself with the LS mounts for 1000 which is mostly likely what I will do. The only real part I dont need from the kit is the cross member since I have no idea where that will mount at the moment.

I did a little more measuring the other day and from what i think with the trans length, using a known shifter relocation (which a custom one might shorten it more if I need), and the adapter plate, it might force me to get creative with the radiator and maybe use a pusher fan to save space. I will know more once i get it on the cradle and in the car. I have already assumed i will be using the corvette/cts-v accessories to save as much space as possible. I have only found one other member on here who has used the 300zx trans. His NA build was a definite budget build but was able to get the shifter to line up with everything fitting by building a custom shorted shifter bracket. Considering the price of the T56 now and the strength of the 300zx trans, i would like to get this working with the v8roadsters cradle so other people can see this as a viable swap option without having to custom fab everything.

pj_mcgarvey

Taylor Ray on youtube used the same trans I think, so I'd check out the details on that.

Tobiczyk

I believe he used the CD009 6 speed from a 350z. For that one you need to cut the bell housing off as it is integrated then bolt on the adapter plate and a t56 bell housing (i think)

Tobiczyk

So I reached out to LOJ and while I expected the adapter plate to be about an inch or so, it is actually only 1/3". I know it isn't much but that does save 2/3", lets call it 5/8" to standardize the terms. Also, in case anyone else is interested, they keep that adapter plate/flywheel kit in stock. no lead times.


EDIT: He replied again and let me know it was a mistype. Actually 1/2" thick for the plate. Still good to know.

ToySnakePMC

Thanks for posting the build on here. I, too, am excited to see your choice of drivetrain installed in one of our V8M’s!
Best of luck and keep us current when you can.

Tobiczyk

I have actually been meaning to post an update. I was able to get my hands on a few choice parts that will really come in handy.

The other day I was looking through the forum and came across a member who posted like 6 months ago that he was going to be parting out his NB. He also just so happened to live less than 10 miles from me. On the chance he still had anything I reached out and he still had quite a lot of stuff left. Unfortunate for him but lucky for me, he never finished the build so most everything was brand new. I was able to pick up a v8roadsters subframe, boss frog rails and crossmember, a professionally depowered rack with welded pinion, fuel lines for the corvette style filter/regulator, some bilstein coilovers with eibach spring and extended NB hats for longer travel, and some spare seats that need recovering but in good shape.


Overall it was a great pickup. I know i am going to need to most likely modify the cross member to work as i highly doubt it will happen to line up with the Z32 transmission. Now i just need to get the transmission adapter plate so i can get it all bolted together and start mocking everything up, see where the trans/shifter lines up. With the bell housing being smaller than the T56 and probably having to push everything forward an inch or so, i think i might be able to get away with not cutting the firewall and tunnel. Maybe that is just wishful thinking but I am hoping for now.

ToySnakePMC

Wow. I’d call that a huge score! And convenient to boot! Your excitement meter had to be pegged when that deal worked out. Appreciate the update.

pj_mcgarvey

Nice, I found my unused subframe somewhat locally too, for half the price of new. It was the first part I bought, and I was like "Well, I guess I'm really doing this then".

Tobiczyk

So I'm out in the garage now looking at the diff and I while the super 8.8 seems substantially bigger, I think it will work (and maybe even with no welding on the cradle).

for the front mounts Im thinking of building a wide U crossmember between the two pickup points on the bottom front of the cradle and up to the ears on the carrier. It would bolt into the exists captive nuts on the cradle.

for the rear, build another member/plate that goes between the two existing diff mount posts and incorporates the rear ears on the carrier. May have to cut off the secondary brackets and relocate if I even really need them.

The spacing all around seems pretty good and the diff would be about 3/4" below the bottom edge of the cradle. I can live with that.

axle location is pretty good too.



And plenty of room on top

This just might work

pj_mcgarvey

You may want to give yourself more room at the bottom for exhaust routing (if needed) and ground clearance. I'd try to keep it above the lowest point which would be your control arm mounting points. Then again I'm not sure how much room you have to work with at the top.

Tobiczyk

I have some room to move it up if I need. Just depends on fore/aft movement. I will get better measurements once I have the rear all cleaned up and can lift it all in place to check for clearances. Worst case scenario I have to notch the cradle a bit and plate it for strength. Worse worst case scenario I have to build a full tube rear cradle to hold everything and still have room. We shall see

cvx_20

Looks to me like you could move it up quite a bit, but the important locator is the centerline of the axles. The axles should be horizontal with minimal angularity at rest, which with the older 8.8 puts the top of the diff pretty much even with the top of the subframe. Basically line up the axle holes in the same location as the original Miata, both horizontally and vertically, because the other end of the axle will be in the same location as the original.

Tobiczyk

I think so too. Can anyone give me a measurement of how much height there is from the top of the cradle up to the floor in the middle? or the measurement of the centerline of the axle to the top of the arch?

pj_mcgarvey

I'll be doing some minor stuff on the car this week, so I'll take some measurements

Tobiczyk

Thanks. I have both cradles out of the car so its difficult to get in there and pull the numbers myself.

Speaking of, had a buddy come by yesterday and help get the front completely stripped. Just to feel like we accomplished something, decided to hang the v8roadsters front cradle. It really is amazing how much more space it provides than the stock cradle. Obviously it needs to come back off but it was nice to know it bolts right in (not that i ever doubted it)

Also was looking around at a few things for the motor. Found a company near me that will CNC port the 799 heads for $500/pair. I don't know how i could pass that up.

pj_mcgarvey

I took a measurement from the top of the axle (not the centerline, oops) to the arch, and I got 33 mm.

Tobiczyk

Thanks. That gets me in the ballpark

Dan_W

I ended up making my diff mount twice... first go-round I didn't account for the rear U-joint clearing the gas tank. Ford 7.5.

Tobiczyk

Good call on that. I will have to make sure i tack it in and hang it before fully welding it up. want to make sure i have full clearance and no issues with driveline hitting anything on full suspension compression.

Also sold off the iron block and crank the other day. gives me a few hundred more for parts. yay.

Tobiczyk

Well here I am, back from the dead. It has been a long few months here in Michigan. With that time came a few changes to the project.

Back in November I was working on getting the car completely stripped and came across a few issues that i didn't find when I was originally looking at the car. For starters, there was a little surface rust on the rear wheel wells but nothing major to speak of. Nothing past an inch really. I brought my usb scope with me and scoped the rails and everything looked good so i grabbed it thinking I had a good example. Unfortunately, I was not so lucky.

During tear down and getting both the front and rear cradles off, i had multiple studs/nuts break free inside the frame and spin. Ended up having to cut the bolts to get the cradles off. For the faintest of a split second I thought about trying to repair them but upon scoping the rails again to see how bad the damage was I could see that someone had sprayed the inside to coverup everything. I guess i just didnt look close enough the first time and never noticed the little bubbling under the paint inside the rail. You live and you learn.

Needless to say my hunt began for a new car to build from. Now being up in the Detroit area, most cars here are all piles of rust and the ones that aren't are 5k+ even if it doesn't run. Just maddening trying to find a proper car for a project. There happens to be a great guy up here who buys southern cars and ships them up regularly to part them out and sell complete rolling chassis. Mostly it is to supply parts to his son and friends who race spec miata. Whatever the reason I was able to pick up another 2000 chassis fairly complete for a great price, with free delivery (lets be honest, that is the best part).

So here we start again.



So the grey in the back is leaving the green is new, which works out well since I wanted to go british racing green anyways. I stripped every usable part off of the old one and added it to storage and decided to just junk it. Not worth the time or effort in fixing it. Also to get back to where i was I started once again stripping the new car to get it ready.

There is definitely something to be said for southern cars. Having a car this clean up here just doesn't happen. I pull the rear cradle and was honestly in shock at how spotless the underside is.


Needless to say, this is a much better platform to start with.

So here we go again, 4 months later I feel like I am already a bit ahead of where I was last time, even if I am a bit behind where i wanted to be at this point.