tbone heller

Be sure to check for spark plug accessibility with your headers installed. I think that one style of GT-40 head had a different spark plug mounting angle, causing the plugs and/or wires to hit the tubes.
Good work on that intake. Hog it out!

Jack Sprat

Yeah the GT-40P heads have the straight plugs that won't work with most headers. They work with the Speedway Headers but that is about it. I'm concerned that they are about 1" wider than other block huggers.

I was going to do the mismatched Hedman headers but they are 50% higher than just a 3 years ago. It's the principle of the matter, well and $100 too.

Thanks TBONE. Once I learned the secret to keeping the AL from loading up the bit, it went much smoother. Still got to polish them but that will be after tomorrow's junk yard trip!

tbone heller

Get you some of this: https://www.fastenal.com/web/product...%20Fluids%22|~

Jack Sprat

Thanks Tbone. I had read that WD-40 will do it and I tried it. Works great to cool and not load up. The stuff from Fastenal is probably much better to extend tool life.

I have decided to go Super Low Budget so I can enter this contest:
Grassroots Motorsports $2014 Challenge: Grassroots Motorsports

I'm already getting closing in on the $2014 limit so I'm going to need some real deals on a clutch, rollbar, and top. I'll probably even have to shorten the drive shaft myself.

I ordered the headers! They should be here tomorrow, then the subframe cutting will commence.

Jack Sprat

Intake is ported and needs to be bead blasted.

Got headers. As expected, they aren't going to fit. Got a lot of cutting to do on the subframe. I think I'm going to make pockets and reinforce the internals with gussets. I want it to drop in real nice like. LOL

charchri4

LOL that $20xx challenge is on my bucket list too Jack! No question a converted Miata would be my first choice but in many hours of pondering I think the only viable way to do it is to use an engine that you can leave the stock Miata rear end in tact. That and find a very cheap Miata with a torsen in it already.

This is now my favorite thread and I am rooting for you all the way!!!

Jack Sprat

Thanks Jim. I'm glad that I'm building something with a chance and I'm going to need some moral support. Got a lot done tonight even though I was exhausted when I started.

I am not familiar with the torsen rear diff. What models did it come in? Can you identify it from the outside? Will it handle a V8 with 300-400 ft lbs of torque?

Thanks!

charchri4

There have been a few builds that have left the diff and with a low power small block it might hold together. It would be fine for the event but you would not want it on the street. The gearing in them is like 4.05:1 and you would scream that V8 down the road with one.

A torsen is the way car makers have been doing posi for the last 15-20 years or so. It's a slick set of gears that wind around each other to work their magic. I don't think a lot of NAs had them but it was an option. I really have no idea how to tell them apart because I know very little about normal Miatas. But I do know there will be guys who read this that do!

By the way my sons idea was to weld the inside of the tbird shaft to the outside of the miata shaft and just be sure to get it straight. The apple didn't fall far from the tree...

Jack Sprat

Thanks to you, I was motivated to get something done tonight. See picture above.

Funny, about the cv shafts, I'm very sure I'm going to do what your son suggested even if I have to make a sleeve to adapt the two. I've done it before with DOM tubing and it turned out great.

I'm thinking worst case, $150 for the entire rear end. No choice but to keep it cheap if I'm getting it under $2k.

Jack Sprat

A Good Night.

More progress tonight. I got enough of the subframe cut that I can see how everything is going to fit. The doubting (will I be able to do this) about the project is over. I am 100% sure I will make the headers work, the bellhousing will fit (with the tranny) and I will have enough metal left to make the motor mounts work. I even see how to box it for strength. A lot of work to do but now I know for sure that it is doable.

Thanks for all the help!

Jack Sprat

More progress. I found a big shoe horn and managed to get the engine sitting in with the headers bolted on both sides. Oil pan is on too.

Got tons more to do but this was victory that I stopped to celebrate.

Haven't painted the manifold or engine yet. I'm going metallic graphic on the engine and still deciding on the intake.

Picked up a pair of Anchor 2235 motor mounts for less than $10 (total) at Advance Auto Parts. Score!

Jack Sprat

While looking over Factory Five's install instructions for the 8.8 IRS. I finally realized why I am so excited about this build. I am essentially building an AC Cobra with pop-up headlights. Since I would never be able to own a Cobra replica, in essence this car will be as close to a dream come true as I will get. I'm good with that, really good with that.

cvx_20

And a real top, and side windows that actually roll up and down.

Mike

5.0MX5

Yep, that's about the size of it. Best thing is you don't have to put up with all the Boy Racers everytime you stop. And the stealth factor is FUN. Of course if you drive around with the hood off the Miata you do get some Cobra like attention. I drove mine to town a couple times recently hood-less, it was certainly a conversation starter.

Good Luck!
RR

charchri4

Click and enjoy Jim and Jenna build diary, Miata LS1 Conversion: Is the V8 Miata really a modern day Cobra?

Jack Sprat

True, CVX_20. It is a real car on the inside.

5.0MX5 Good idea. I'm sure it would get stares everywhere without the hood. I'll have to try that.

Jim, I checked out your link. Excellent job on the comparison. I had no idea they were that close. Back in the 80s I read a magazine with the Cobra 427 specs and was blown away. Can't wait to finish my car!

Made the mistake of buying a roll bar, then found out it is a style bar. I'm going to reinforce it with some DOM tubing then wrap it in carbon fiber.

tbone heller

I would suggest selling the style bar & getting a roll bar. The roll bar really stiffens up the chassis, especially if you incorporate some door bars.

charchri4

+1 ^^ for sure! Unless it blows the 2014 budget then I would just make my own start to finish.

If you want to go cheap and use a kit this is what I used. http://www.rhodesracecars.com/90-98-...A_c_10658.html

It is quite a bit of work to fit and if I was going to do it again I'm not sure I would.

BTW If you do the kit don't use the duplicolor roll bar paint everyone says is great. John Deere Blitz black tractor paint is way more durable and half the cost.

Jack Sprat

I agree. I hate the (don't want to) Roll Bar. I got it for $70 and I need it at that price for my GR 2014 Challenge. Drove 2 hours to get it and should have just drove home empty handed. The website didn't have anything about style on it, got home and saw it in the instructions.

Charchri4: How hard was it? How long did it take?

charchri4

This is the way it comes,


If there was a bend about half way down each leg of the main hoop it would be so much easier to work with. With out that bend it either has to tip backwards about 15 degrees or you really limit your seat travel. I just cut the thing off and put it in the way hard dogs are done because even with a bender it would limit seat travel to take the legs to the floor of the car.

I'm on the road and have a lot more photos at home I can send you but there is a little on the first page of my blog here
Jim and Jenna build diary, Miata LS1 Conversion: Weekend 1 the journey begins.

For me it was the first time I ever pulled the trigger on a welder so that had a big impact on how hard it was to do. I had no idea welding the diagonals to the center of the hoop would warp it so much. Also I did not make it like the factory cuts with the bar going side to side but did diagonals instead.

As far as the kit goes it is good stuff. It is the proper NHRA and SCCA tubing that weights a ton and they give you plenty of it. I bought the 8 point version to have extra tubing to practice welding on but if I did it again I'd just do the normal 4 point. BTW if you buy it check on on ebay. With the ebay bucks back it is a little cheaper than the web site I posted. I'll be home next week and can put up more photos for ya.

Jack Sprat

Wow, that looks way better than my stainless steel exhaust pipe 'roll bar'. In fact, I think I'll cut it up and use if for my exhaust. I'd have a lot of Jbends. LOL. Maybe it could mount to the mounting bases once I cut old roll bar up.

Jim, if it's not too much trouble, when you get back home could you upload some more pics.

Thanks!

Jack Sprat

After 2 hours of wrenching in the mud, I scored a 3.27:1 geared 8.8 aluminum diff and half shafts. Thanks to my son, Jake it wasn't that bad - two hours start to finish. Cool thing was that we were able to remove the shafts without going into the boots and they popped out of the diff with no problems.

Got to clean it up but I'm stoked to have found one!

[IMG][/IMG]

Nowak1981

Gratz! What did you pull it out of?

Jack Sprat

Thanks!

It was hard to find but we pulled it from a 1998 Lincoln Mark VIII with 120k miles. It cost me $150 but it was worth it due to the low miles and having the exact gear ratio I wanted.

Based on others' feedback and my calculations, 3.27:1 is the best gear ratio for my application.

There is a Mark VIII with a 3.07:1 ratio (unknown mileage) in Wilmington NC at Cape Fear Pick N Pull if anyone needs one. Their inventory is posted online so check before you go.

Cape Fear Pick N Pull

Jack Sprat

Well, I had no luck getting the hub broaching done locally so I contacted Martin at Monster Miata. He is a great guy and has given me some really good advice. I am going to have him broach my hubs for me. He also talked me into the 7.5 hubs which will save me some trouble with shock mounting and will be plenty strong enough for my car.

Buying some .120" wall 1 1/2 in. tubing from Summit Racing and a hydraulic pipe bender. I am planning to make my own roll bar and exhaust. I hate I wasted $70 on the style bar but at least it won't go against my total.