Make Your Own MAX

The plans and links and parts you need to build your own.

(Latest update April 11, 2013)

photo by Royce McCornack, courtesy of Mother Earth News

Here’s the scoop on making your own low budget high mileage sports car. My own example (MAX, shown above) gets 100 mpg at 55 on the highway and cost me less than ten grand, which ain't bad for off-the-shelf technology.

photo by Doug Snodgrass, courtesy of Mother Earth News

We've classed it up a bit with a new molded body, with a ragtop on the roof and no duct tape on the nose, but it's the same old MAX under the skin, now with over 100,000 miles of test driving to its yeah, we're pretty comfortable we've got the bugs worked out of it.

Other than body, powerplant, and donor car, MAX is an ordinary Locost—not that there’s really any such thing as an “ordinary” Locost. The chassis follows the original dimensions set down by Ron Champion, who wrote Build Your Own Sports Car for as Little as £250 and started a movement.

The Locost (so named because it’s low cost, and because the author’s obvious inspiration was the Lotus Seven) is a DIY car built from a Ford Cortina, which was a small sedan littering Great Britain’s wrecking yards at the turn of the century. Locost have been built by the thousands, and the builders range from high school students looking for a shop project, to guys my age who’ve hankered for a Lotus Seven for the last 50 years.

Cortinas have never been popular in the US, and so most American “by the book” Locosts have been built from early ’80s Toyota Corollas, from back in the days when Corollas were rear wheel drive. They’re still out there—the Corolla was once America’s most popular car—and they’re pretty cheap nowadays because the running gear was much more robust than the bodies.

So if you want to build yourself a car that’s just like MAX…

(By the way, after considerable deep thought and discussion and a couple of mind-changes, we’ve decided the full model name for this type of car is: the Kinetic Mk1 MAX, or just plain MAX for short. I was hogging the name for a while, saying mine was The One and Only MAX, but I got outvoted by public opinion. So MAX it is, and we threw in the Kinetic because we're strongly considering making a kit for folks who don't want to weld and it'll be under the Kinetic brand. And it's the Mark 1 because hey, we're not done making cool cars.)

…you’ll need to get your hands on a RWD Toyota Corolla with manual transmission, and a copy of Champion’s “Build Your Own Sports Car…” book. The only difficulty with the book is, in the time since the MAX project started, Ron Champion’s book has gone out of print. There are still lots of copies going around, but unlike the Toyota, the books have gained value. Again, they’re not scarce, but they’re popular, so expect to pay more than their initial list price of $33.95. I bought a copy (Used - Like New) off of in July '12 for $50 plus $3.99 shipping, and there was another copy there (Used - Good) for $55.80 with shipping included, so don’t be stickershocked when you google it and find copies for sale for $600.

Sixty dollars is reasonable (though you can probably beat that with a few minutes on the internet), six hundred dollars is not, and the reason those $600 ads stay posted for years is because nobody buys them at that price. When that book went out of print, a number of folks ran them through a scanner and posted free copies on the ’net in pdf form, but I prefer the actual book myself.

If you’re experienced and daring, you might go ahead and skip the book. Jim McSorley offers excellent (better than the book, in fact) free chassis plans for the Locost on his Sevenesque site,

Just go to Jim's <Plans> page (it's the third menu item on the right of his main page, just below the pic of the miniature red sports car) and click <Download> or download the plans from here. He also has free plans for slightly larger versions, for people using larger engines (and for larger people as well), such as the McSorley +442, which is 4” longer, 4” wider, and 2” taller than a “book” chassis.

Another common resource for how-to instructions is the successor to Champion’s book; Build Your Own Sports Car: On a Budget by Chris Gibbs, available today on Amazon for $22.27, which gives plans for an updated version of the Locost  (they call it the Haynes Roadster) with independent rear suspension and a 2” wider chassis.

If you base your build on this book, your car won’t be Just Like MAX and you’ll need to tweak the chassis a bit and adapt some different parts (for example, that 2” makes the chassis too wide to fit the Corolla rear axle), but it’s an intriguing alternative, and one of our beta-testers is building a Haynes-based MAX with a Mustang II axle.

The obvious advantage (along with the advantage of the book being in print and available at your favorite bookstore) is it gives another inch of cockpit space to both the driver and the passenger, and if the extra width drops fuel economy from say 100 mpg down to 98 mpg, that works out to one extra gallon of fuel every 5000 miles so I think you can live with it.

My colleague Lonnie Smith (he and I are active members of, which is the information clearinghouse for North American Locost builders) made a digital model of the Haynes Roadste (in grey)r, and rendered it in combination with the original Locost (in reddish), so you can see the difference between the two chassis.

So if you don’t want to make your MAX quite exactly like my MAX, you have lots of options, and if you have questions, I’m as close as your email; write to with the subject <Building KV MAX, questions> and I’ll get right on it. For now, we’ll assume you’re building a MAX replica; you built your chassis by the book and you’re ready to rock. Here’s what makes MAX different from the usual Locost.

Click to the MAX: Mother's Automotive eXperiment page (or click the <What's New> button at the top of this page and click on the photo of the green roadster) and see how we did the first couple of these cars. You’ll note that we thought about MAX for a year, then spend eight months making the first prototype, and you’ll also note that we made the second MAX in three months. That’s because we had lots of time invested in figuring things out, and once we’d done so once, we didn’t have to figure them out again.

Installing the Kubota D1105T engine

Let’s get the most challenging part out of the way first. Not surprisingly, we couldn’t find a Kubota-to-Toyota engine/transmission adapter, so I had to design/measure/translate/carve/machine my own, and doing that once was more than enough, so this summer we had half a dozen of these adapter plates cast and machined, so nobody will have to start from scratch making their own. The kit, including the mounting hardware, is on our <Locost Parts> page (there's a button at the bottom of this page) for $350.

In keeping with our information-sharing philosophy, we can provide you with the G-Code that runs the CNC mill that surfaces, drills and threads these adapters. There’s no drawing for these parts or for the foundry pattern for the castings, but if you’re a hard core do-it-yourselfer I could make you temple rubbings of the pattern that you could trace that onto a 1-1/4” aluminum billet. Out of sportsmanship, any parts we make or sell at Kinetic were deducted from the $10,000 build budget at retail price, but you can probably beat our $350 price by a hundred bucks or so by making it yourself, which works out to about 70 cents an hour.

You will have to modify the Kubota flywheel to accept the Toyota transmission input shaft pilot bearing, which is a 12mm bore, 28mm od, 8mm width, sealed both sides ball bearing (Timkin part # 101SS and there are many other manufacturers).

The clutch friction disk is from an 81-88 Toyota Tercel DLX or SR5, the clutch pressure plate is from 89-91 Suzuki Swift, 95-97 Geo Metro Lsi, or 89-01 Suzuki Esteem (e.g. Exedy SZC 509), and your local auto parts store can get you both. You’ll need to drill the six mounting holes in the pressure plate with a letter “O” drill, to make it fit the Kubota flywheel.

To make the engine fit nicely under your hood, you’ll need a 90 degree thermostat cover, which is Kubota Part #1G25373260, so the hot water outlet isn’t pointed straight up as it is in tractor and generator applications. I also suggest you lower the engine by replacing its standard (and quite tall) oil pan with a shorter one; Kubota Part #17523-01500. You can either shorten the oil pickup tube that came with the engine, or replace it with Kubota Part #16261-32117. These parts should be available from your local Kubota tractor dealer, but if you can't get the parts locally (or, in fact, can't get an engine locally) contact us and we'll get them coming your way.

The Body (bodies, actually)

The traditional Locost Lotus7ish body, as shown on our Escape From Berkeley car (above), is amply developed and readily available (Kinetic has delivered over a hundred Locost noses, for a point of reference). It’ll set you back $1000 to $1500 depending on how fancy you get ($1320 retail for  the body parts on MAX #1).

You can piece together MAX’s streamlined LolaMk1ish body (the photo at the start of this page) the way I did in my MAX Updates blog (from MAX Update No. 45: Body-Building Time Crunch through MAX Update No. 73: Fenders Sans Benders) for about a grand-and-a-half more than the Locost body, but I think you’d rather not because it was a heck of a lot of work. It doesn’t take any more materials to make a whole fiberglass body from a mold than it does to make one bit by bit, so in theory a fairly finished body costs the same as the bunch of body fragments.

In practice of course, there’s the cost of the mold, which starts with the cost of the pattern, but enough folks have been asking for these bodies that I bit the bullet and I’m having molds made. It’s a tiny bit scary because making the pattern called for sacrificing MAX’s nose to the cause, and because it took a bunch of work getting the nose nice enough for a production mold, but the pattern- and mold-making job only has to be done once and we can spread the cost over a lot of bodies (knock wood).

So the production Lolalike body (which we’re tentatively calling the Lalo, tee hee) isn’t on the parts list yet, but we’re determined to keep it under $3000, which still keeps MAX on track with its ten grand budget. And we don’t have mounting instructions for that body yet, but we do have three body-beta-testers to mark up my first draft, and if you’re starting now then we’ll have bodies and instructions before you need them.

Future Developments

The big one is the enclosed cabin, which I intend to have on MAX this summer, and which will bring me right up to the $10,000 mark—but you have one budget advantage that I lacked; I had no choice but buy a brand new Kubota D1105-T for $4500+ because the xx05-series Kubotas hadn’t been out long enough to show up on the used market, and now a quick internet search has them popping up between $1000 and $2000. I scanned Craigslist the day this Build-Your-Own-MAX page went live (July 17, 2012) and found this ad for a D1105-T in Jacksonville FL...

... for $1200, with a Toro riding lawnmower attached, and in the <Few LOCAL results found. Here are some from NEARBY areas...> window, found this D1105 engine in Gainsville for $1500.

I've cropped these two ads to fit the page, and I've blanked out the "reply" info because these two are sold already, but there are others out there on the used market, and the internet makes it easy to look for them.

And there are other options. Any of the Kubota 05 Series engines will fit this adapter, they have seven xx05 engines in production, ranging from the three cylinder normally aspirated 24 horse D1005 through the four cylinder turbocharged 44 horse V1505-T. The D1105-T (three cylinder 33 horse turbo) suits me just fine—I can squeeze 100 mpg out of it without holding up traffic, and I can go 90 mph if I want an expensive speeding ticket, so I’m solid. We’re also building an LRR with a Suzuki (Geo/Chevy Metro) gasoline engine, a “MAXine” if you will, which will be more convenient for some folks, offer higher performance, and deliver fuel economy in the high two digits.

This page is a work in progress, so check back now and then if you want to know the latest, and if you’re ready to start building right now, please contact me and we’ll see if we can get you a spot as a beta tester.

dwg test

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