Jack Sprat

I purchased my 93 Miata with a blown engine and equally bad convertible top. I did not plan on doing a conversion but the only engine I could find for it was being sold by a very shady dude who could not read an odometer. No Thanks.

After several days of research I was still on the fence. Then I found this forum and saw how helpful everyone is so I am going to do it! Tomorrow, I will officially be at the point of no return when I buy a used T5 setup for the 5.0 that I built a few years ago (never even started it, long story).

The Miata's engine block has a hole in it and one piston's connecting rod was feeling a little disconnected. Never seen anything like it - see pictures.

This is definitely going to be a very low budget build because I'm putting a kid through college. My 13 year old son will be helping so I think it is a good father son project.

tbone heller

Looking forward to seeing your progress.

Jack Sprat

Spent a few hours driving around to buy parts. Scored a complete T5 setup for $450 that is a little dirty but in good condition.

Didn't get as far on dismantling the Miata as I hoped. Some things were a real pain. The exhaust was the easiest I have ever removed though.

I hope to have a picture of the empty engine bay to post tomorrow. Wish me luck.

charchri4

Oh you are a lucky man for sure Jack. I would love to build a car with my son and some day it will happen.

I really appreciate you doing this thread and am excited to see how you guys tackle things. Good luck!

Jack Sprat

Thanks Jim.

My 18 year old son helped me on several projects, most notably, the engine build on our 05 Mustang GT. It was my first tuning, forged internal, and turbo install. It was big success - we achieved 500whp and 24mpg. It's a blast and honestly, I couldn't have done it without him.

My 13 yo son is starting to be a really good helper. It's making the project more enjoyable since it's a good time for us to catch up on life.

Jack Sprat

Got the engine & trans pulled and realized that I am really just at the beginning of the project where the modifications and fabrication start. Got lots of new cuts and bruises but my spirits are still high.

Jack Sprat

It took a while but I was able to get the clearance cuts roughed in.

Jack Sprat

I don't know if everyone else did this but I just had to see if it would fit in the car. It fits!!! I am just about as amazed as if I had just seen bigfoot!

The engine has been sitting about in the garage for quite some time. I am going to spiffy it up and make it look nice as time allows.

Jack Sprat

I spent a lot of time in the U Pull It lot this morning. Mainly looking for a rear differential. I found several Thunderbirds and Cougars with axle codes Y (3.08) and 5 (3.55) - no lockers and no Lincoln Mark VIIIs either.

I did notice that the 3 02 Ford Explorers had IRS and it looks like an 8.8 with an Aluminum housing. Checked the codes and two of them were D8 which is 3.73 Locker. I haven't seen anyone recommend them but it looks like it would work since I'm going to be making my own mount anyhow.

Here is a link for removal which has a ton of picks:
How to: 3rd Gen Aussie Locker Install - Ford Explorer and Ranger Forums "Serious Explorations"®

What do you guys think?

cvx_20

A couple of thoughts: What are you doing for axles? Some of the Explorers have 31 spline axles which is a problem if you want to use the FFR axles, as they are only 28 spline. Not a problem if you go a more custom route.

Also it appears to me that the rear mounting scheme takes up a lot of room right where you might want to run exhaust. I haven't actually tried an explorer rear, but I have seen a post where they actually cut the mounting ears off and used a bolt-on mount. I suppose you could use the rear cover from a T-bird if you had an extra.

Mike

Jack Sprat

Thanks for responding.

I haven't started researching the axles. I thought, worst case, I use the 8.8 shaft cut and spliced to the Miata shaft. Was planning to use a steel sleeve (that matches the two shaft diameters) welded to the ends of the shafts to join the shafts together. I don't know if the Miata section is going to be strong enough though.

After I posted, I found a company that makes a kit that uses this rear. It is a very unusual setup that uses the 3 mounts. I'm not very fond of it, I'll do something different for sure.

Thanks Again!
Jackie

charchri4

Front mount looks about the same but the back mount is a concern. If it would clear the rear part of the frame to tuck up you would be golden.

Everything is different inside and the part # for the axle seals are different too so I doubt Martins axle shafts would work. You'd have to run the numbers both ways but my guess is it would be cheaper to pick up a bird diff on car-part.com or on tccoa.com and use Martins shafts than it would be to build custom stuff for the Explorer. I got my 8.8 3.27 locker for $100 shipped and I could have run it as is if I didn't want to swap to 3.55 gears.

Speaking of gears 3.73 is pretty tall for a T5 trans and you would be spinning near 2500 rpm on the hwy with them. Most guys run 3.27s with T5s.

tbone heller

Any GOOD salvage yard should be able to locate what you are looking for. I opted for a 7.5 open 3.27 differential & installed a new limited-slip carrier as well as all new bearings & seals. If you can locate a used locking assembly, chances are it will be worn out & need new clutches anyway.

tbone heller

As far as the 8.8 Explorer differential goes, I have had the pleasure of rebuilding hundreds of them. It appears that the aluminum case expands with age, causing the backlash to change, thus making them whine like crazy. The only short-lived repair would include a new ring & pinion.

jreid1000

Welcome! This forum really does have some super helpful and skilled builders. What area of the country/world are you located?

Jack Sprat

Thanks for all of your responses and help!

Charchri4: I was thinking the 3:73 would not be good for cruising. It's good for drag racing but that's about it. I want my car to be able to cruise too. Right now, I can find 3.08 or 3.55. Will have to look on Car-Part.com for the 3.27. What RPM are you running at on the highway?

tbone: I was curious why I saw some Explorers with missing axles. Thanks, I'll stay away from them. It looked like a PITA to mount it anyhow.

I live in Eastern NC near Greenville. I need to add that to my information.

mazdaspeedmiata

try call Factory Five racing
I am 90% sure they have 31 spline axles for 01-04 cobra diff
i assume those will fit in the explore

please report back

Jack Sprat

Based on the previous responses, I am going to stay away from the Explorer rear diff. Just gonna keep it simple with the Tbird 7.5 and put a locker in it later. There are a lot more builds with it so it looks much easier to mount.

charchri4

1600 at 60 but keep in mind I'm running a T56 with the .5 overdrive 6th gear. Fun to see the 4cyl guys freak out at this shot...

Jack Sprat

Charcri4: That's a nice overdrive. My T5 is jealous!

I did manage to get some work done on the car over the weekend. I got the rear rear diff dropped and the rear subframe wire brushed for painting. I hope to be able to do all the differential mounting mods without dropping the whole thing but that remains to be seen.

charchri4

Oh man it's only 6 bolts to drop the thing and very well worth the time to drop it. Even empty the diff housing weighs 30 lbs and sooo much easier to not fight gravity or weld laying on the ground.

You've seen this post right? Jim and Jenna build diary, Miata LS1 Conversion: The other half of the back half

BTW it's really handy to be able to drop the gas tank down a bit to and run the fuel lines to it and the subframe has to be out to do that.

tbone heller

[QUOTE=Jack Sprat;7636]Thanks for all of your responses and help!


tbone: I was curious why I saw some Explorers with missing axles. Thanks, I'll stay away from them. It looked like a PITA to mount it anyhow.

The most likely reason is that people came to get the rear knuckle assemblies (the hub bearings are another area known to have issues, are a PITA to replace without special tooling) & did not have a 36mm socket to remove the c/v nut, so they took the axle with them.

Jack Sprat

It has been a great day. Hauled off some scrap stuff to raise project capital since my investment request was denied by management (wife).

Went to junk yard and found a factory ford aluminum intake manifold for $28 and some GT40P heads for $115. Didn't have my tools so I'm going to go back asap. The part finds helped me make my final decisions.

5.0L, carbed with ported Ford AL intake
m-6250-e303 CAM (282° 282° .498 .498)
GT40P heads -requires Speedway Motors block hugger Headers:
Small Block Ford Block Hugger Tight-Fit Headers, Plain - Speedway Motors, America's Oldest Speed Shop
Trans - T5 with 3.35 First .68 OD
7.5 Open Diff (at first) with 3.08 (or 3.27 (not sure yet)) gears
Quiet exhaust (no droning) with cutouts for racing

Jack Sprat

Picked up the intake yesterday. It is a factory Ford 4 barrel from an 84 Mustang GT. The ports are tiny so I started porting it today so it would match a GT40P head.

Jack Sprat

Been hard at work porting the intake. Tomorrow I order the headers. I have decided to try the Speedway headers. They said they would take them back if they don't work and I don't damage them.