Hey everyone, ive been a lurker the forums for a while now gathering my thoughts for MY build

I'm almost done with university for the year and am planning on doing a majority of the build over the summer. I want to do all the work myself, no prebuilt chassis or anything.

I am planning on building a McSorley book chassis with a miata donor. I am going to use the rear subframe (IRS), engine, transmission and anything else that is salvagable.

Some questions/concerns im running into (even though its just the planning stage) is the availability of the donor. I can find miatas for $2-3,000 in the US but they are nice miata's with low miles - no junkers (which is what i need). I contacted my local Pick-A-Part salvage yard and they want to sell me a rear subframe for somewhere around $4-500, which i think is a lot. If i sprung and just bought a full miata would that account for most of the cost of my build?

Another concern is with the rear subframe. Ive seen all the pictures and build diaries of people bolting the rear subframe straight to the chassis but i cannot find any descriptions of the build. From looking at the pics it seems like its a standard book chassis that they chopped the rear off and created new bars to bolt the subframe to. Is this correct?

With all this in mind, do you think i should build a +442? I want to build as small a car as i can get away with so, in my opinion, the +442 is overkill. However, without the donor it is hard to decide how wide the car should be.

I have access to Solidworks and I have a basic knowledge of it. However, its very hard to design the rear end without measurments of the subframe. Has anyone seen these measurements on the net anywhere?

Well, this got way too long... any suggestions? Comments? Flames? Please let me know what you think and ask me questions!!

http://www.flyinmiata.com/

There's also a book on how to build a locost based on the Miata - written by one of the guys behind Flyinmiata

Try searching for MX5 on these forums - that's what it's known as over here.

Found it...Keith Tanner is the guy's name...sometimes found lurking here...

http://www.flyinmiata.com/index.php?deptid=4515&paren tid=0&stocknumber=46-86005

[Edited on 20/5/06 by stevebubs]

Thanks for the response. Yes, that website is where ive gotten almost all of my information but i cant for the life of me find what type of chassis they are using. They didnt build it themselves, looks like CMC built it. Any ideas on if its a book chassis or what?

I should probably go and buy his book huh?

I bought Keith's book, and it's fantastic - I read it in a single evening. No matter WHAT kind of build you're doing, it's worthwhile. And Keith has done exactly the build you want to do. By the way, he is very friendly, answers emails promply and is extremely helpful - a great resource. On the chassis note, we built two McSorely frames, and found his plans to be easy to follow, and absolutely exact. He can do anything from book plans to 4+4+4. Building from his plans was WAY easier than trying to do it from Ron Champion's book!

Thanks guys, i just ordered the book... cant wait for it to get here. Does he explain what chassis he used or how to build the chassis to fit the miata bits? Also, where do you guys get your donors? I know its probably different here in the US but i just need ideas. Thanks.

I wrote a big response, but forgot to log in--and thus lost the post. So now, for the truncated version...

I used a custom Bob C suspension that I modified for my own use. My website is being revised, but I can send you ny old website on CD. The miata is a great donor. I bought all my donor bits for $250, not including diff, engine or gearbox. Let me know offline if you want the CD. Or check back on my website for the updated version.

--Chris

Chris, inboard rear suspension
Nice

quote:

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Originally posted by pucksaver


I am planning on building a McSorley book chassis with a miata donor. I am going to use the rear subframe (IRS), engine, transmission and anything else that is salvagable.


With all this in mind, do you think i should build a +442? I want to build as small a car as i can get away with so, in my opinion, the +442 is overkill. However, without the donor it is hard to decide how wide the car should be.

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Thanks for the kind words, guys!

I got lucky. CMC didn't deliver a lot of "Miata" frames before flaming out of existence. My frame doesn't use the rear Miata subframe, just the uprights.

Coveland now sells a similar design. You can find them at http://www.coveland7.com .

If you want to build your own, Mark Rivera has done a lot of 3D work on his frame. His build can be found at http://rivera.fotomojo.us/g/MX7 . He might be convinced to share his design and I think it will end up on McSorley's site. The nice thing about using the Miata subframe like he did is that a lot of fiddly fabrication is handled. You simply have to find a way to mount the subframe to the chassis and provide an upper mounting point for the shocks. The rear geometry is just as adjustable as the front. You'd have a pretty wide front frame to fit the front control arms on the car, so I'd recommend sticking with more of a Locost design for that.

The US never got the later 1.6 engine. The 1.8 cars have a stronger ring and pinion and more power, so 1994-95 might be your best bet. 1990 models are the cheapest and the crank nose problems aren't difficult to deal with if you maintain the car well and catch any wear early.

It's pretty easy to sell off enough parts to bring the purchase price of a Miata to free. Watch Craigslist and the local club and you should be able to find a cheap and ugly car. In SoCal, you are amongst the greatest concentration of Miatas in the world

I don't follow this forum as much as some of the others, but feel free to contact me directly with any sort of questions.

[Edited on 23/5/06 by Keith Tanner]