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Rotus with Mazda 13-B turbo


w650gb500

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I picked up the Rotus that was listed on the Washington DC CraigsList this past weekend. It was listed with a bunch of stats from an old Rotus brochure but only very brief description of the cars current condition. I was able to speak with the owner, but other than a few of the bits that he replaced, he didn't know much about the mechanical condition of the car. That's fine as I'm familiar with both the Mazda rotary engine and Lotus 7 kits. I raced Mazda's for many years(RX-2's, RX-3's, an RX-4 and numerous first generation RX-7's) and have built several different Lotus 7 replicas(RM-7's, RM-8's, a Rotus and an original Arch chassis 7).

 

i probably paid a bit too much for the car, but the seller was firm on his price and since it was Carlisle Import and Kit Car weekend, he was getting ready to trailer it up there and sell it. I decided to take the plunge and buy the car. After a 4-1/2 hour trip south, I loaded it up and headed back home. 9 hours on the road, 2 tanks of fuel and some crappy fast food later, its now resting peacefully in the shop.

 

I took a quick look at the car and it needs some "love". Here's the short list.

- the radiator needs to be moved forward and have proper ducting fabricated.

- after the radiator gets moved, the air intake needs to be relocated.

- the wiring needs to be cleaned-up big-time!

- find and repair the rear differential leak.

- fix the broken emergency brake.

- install the included clamshell fenders and make some supports.

- cut-off the crappy roll bar and build something that will be SCCA legal.

- purchase new seat belts.

- install a steering wheel quick release.

 

All in all, not a bad car. A few weekends worth of work and it will be a nice summer ride for my father. Oh yeah, I forgot to mention, I didn't buy it to drive it myself, I bought it for dad. I've had his RM-8 kit in the shop for 2 years now and simply don't have enough time in life to work on it. I have been apologizing to him for not being able to find time to build it, but with work, building a new house, a fiancée with some medical issues, it was easier to buy a car for him to play with. He can take mom for ice cream or go to a trackday with it, it's his as far as I'm concerned and hope he enjoys it. As soon as we fix those couple items we will see if its more fun to drive than my Miata V-8! They should both be fun but in very different ways.

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I think that is a pretty good purchase. Sure there is some work to do but the fundamentals are there and the price was not that bad when you consider the power potential out of that engine package. Its always concerning though when a seller has no idea of what they are selling! Congratulations on the purchase.

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No, I did not convert this one, I purchased it already done. It's a unique car. It was built for the 2003 Grassroots Motorsports Challenge which it won. The car was so well built that they ended up changing the rules as to how the cars could be built and the team budget spent. Here is a build log for the car since I picked it up. Not much progress lately, but hopefully in the next month or so things will slow down at work a bit and I can get back in the garage.

 

http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/my-new-rebuild-the-mongrel-miata-20/99962/page1/

 

Here is some reading from when it was built:

http://grassrootsmotorsports.com/articles/mongrel-motorsports-miata/

 

i also picked up a complete Monster Miata kit and plan to build a mild street car over next winter.

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If you search around, there is some info on some of the Rotus replacement parts floating around here.

 

If you need additional help, I can put you in touch with one of the guys who used to work at Rotus back in the day.

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  • 1 month later...

*** HERE IS A LINK TO PICTURES: http://s31.photobucket.com/user/w650gb500/library/Rotus?sort=6&page=1 ***

 

Not much time to work on the car lately, but I decided to play hooky from work yesterday and get in a few hours of shop time. I decided that the rollbar needed the most attention, so that's what I spent the day working on.

 

 

The sawzall and grinder made quick work of the old POS bar that was on the car. After taking a good look at the bar, it seems like someone did a half-a$$ job of attempting to shorten the overall height of the bar. Unfortunately they FAILED in a big way! It's no longer a problem, just scrap tubing.

 

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I took a while looking at how I was going to build the new bar and rear down tubes given the structure in the back of the car, or lack of structure in this case. After measuring for an overall height and bending the main hoop, I decided that instead of traditional rearward facing down tubes, I opted for a second rear hoop as bracing. Then came a symmetrical "X" in the plane of the front hoop which will give me a place to mount some sort of headrest.

 

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Standing back and looking at the bars reminded me of my old Reynard formula ford(double roll bars), so I decided to go get some 16gauge sheet, hole saws and dimple dies and see what comes of it. It might not be to everyone or anyone's liking, but its different and I think a cool look.

 

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I'll try to finish weld everything this weekend and post some finished and painted pictures.

Edited by w650gb500
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Now that is a beautiful rollbar! I absolutely love it. Creativity gone right.

 

You know, I've daydreamed about getting a cheap lowcost that didn't look that good and building a one-off body for it based on something sexy like an Auburn or such rather than keeping the 7 look. If you've got a car like that, why not try some stuff you wouldnt try on an expensive Cat, Birkin or Westfield etc.

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Have a question. How does the intercooler location work out? I have a Superformance S1 that is getting upgraded to a fresh T-ll street ported 13B and have considered a "close to cowl" location as the frontal area is used up with oil and water cooling and the more rear location would be much neater. Had cooling problems with old na engine with the original S1 radiator and oil cooler but it was tired. Now have a fb alm radiator and a fc oil cooler with a beehive in reserve for added oil cooling if needed. It is not easy being different. thanks, John

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John,

 

I wish that I had an answer for you. I purchased the car a few months ago, showed up at the sellers house, had him drive it up on the trailer and upon arriving back home, rolled it into the warehouse. I may have started it twice to this point!

 

I've been too busy to work on it but hopefully in the next few weeks I'll find some time. Honestly, I don't see how it could be very efficient in its current location, but for a street car it will work until the winter when I will look at repositioning it and getting some airflow into and out of it.

 

Sorry I couldn't be any help.

 

Dan

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  • 4 months later...
Dan,

 

Is that a crossle FF next to your 7?

 

Good guess and close....

 

Its a Lola T644E Formula Ford that was converted and is now powered by a Suzuki GSXR-1000. It runs Formula-S or

F-1000.

 

Link to pix: http://s31.photobucket.com/user/w650gb500/library/Lola%20T644E%20%20%20Formula-S%20%20%20F1000%20%20%20FB?sort=6&page=1

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Edited by w650gb500
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  • 1 year later...

It's been a hectic year with new house, a new commercial property, business obligations and an ill fiancée. I've been trying to sneak some time in the shop to work on the V-8 Miata(rollcage), the MGB V-8, the RM-8 build that I'm trying to get done for my father and the Rotus. I should have been in the circus as I've become quite good at juggling.

 

The Rotus is getting a set of clamshell fenders installed. I mounted them, make support brackets and they are at the bodyshop getting painted. Matte black I think will look good, so we are going that route and will see if I'm right or wrong. With doing the clamshells, the offset of the front wheels was wrong, so I regretfully removed the Panasports and picked up a set of XXR's in 7's and 8's in the proper offsets. The only thing that needed to be changed were the rear axle studs. The new wheels have a much thicker hub, so I bought some ARP extended studs and pressed them in.

 

Next while looking around the engine bay, I noticed the "handy work" of some previous owner! It's unbelievable what some people will do! I looked at the radiator and fan set-up and upon close inspection, someone had them both held in place with 3 pieces of safety wire strung right thru the aluminum radiator! I removed their "mounts" and fabricated correct mounts for the radiator and purchased a new SPAL fan. I need to made some ductwork to the opening in the nose and the cooling system should work well. I also cut and welded the thermostat housing and clocked it in a different direction to eliminate about an extra foot of upper radiator hose. I purchased SAMCO hoses for both upper and lower radiator connections and with the proper angles, eliminated ALOT of unnecessary hose. Finally I made some custom length sparkplug wires and eliminated about 18" of extra length that was there. I guess someone just bought stock wires, threw them on and coiled up the extra length.

 

http://www.usa7s.net/vb/attachment.php?attachmentid=12193&stc=1

http://www.usa7s.net/vb/attachment.php?attachmentid=12194&stc=1

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Edited by w650gb500
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