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Learning how to build Lotus Seven replicas...together!
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PostPosted: Tue May 06, 2014 6:01 pm 
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Location: Boulder, CO
It is finally time to start my build log, coming into summer vacation this year. Brace yourself, this first post will be long.

A bit of background about me and the build: Over the weekend, I celebrated my 22nd birthday, and celebrated the day finishing the welding on the main part of my Haynes frame. I am currently a student at a local community college, and will be studying Precision Machining and CAD/CAM starting in August. I also manage a local pizza shop part time, and that, combined with random work on friend's cars, is how I fund my projects. I have been going to race tracks and autocrosses and riding in different cars since I got my first helmet at age eleven, and have always been into cars. As soon as I got my driver's license I started autocrossing, and started doing track days and driving schools shortly after. I am now a qualified autocross and high-performance driving instructor for my local chapter of the BMW CCA, and will be getting my racing license through NASA as soon as money permits. My personal experience with racing has been mostly autocross and drag racing. I worked at a shop that worked on trucks and trailers for some time, and spent the evenings building drag cars. My first car build ever was a 1988 S10 :chev: that was converted to a 13.7s car in 12 days following mine and two friends' high school graduations. Following that job, and a failed attempt at mechanical engineering school, I landed a job with a small exotic race car shop in my home town. I serviced and helped build several interesting cars, including Dan Gurney's Lola T70 from 1967. I left the shop after much verbal abuse from a coworker, and unfortunately the owner of the shop has since passed away. I bought a Hobart 125 welder, and taught myself to weld immediately before this project.

The car is a modified Haynes Roadster frame that I have built in my parents' garage over the past two and a half years or so. The frame from the nose to the rear firewall is complete, and I am going to have to redesign the rear suspension area, as I am not using the Sierra rear end.
Attachment:
File comment: Haynes frame with bonus GTS-2 racecar.
Frame.jpg
Frame.jpg [ 576.23 KiB | Viewed 1090 times ]


I started the project planning to use a complete Miata as a donor, and found a 1990 that had made too-close friends with a tree, and bought the whole car for $550, sans differential and seats. Over a week I stripped everything usable out of the car, and had the chassis taken away for free by a local wrecker. Since then, I have sold several interior and electrical parts, as well as the engine, as I had a change of heart for the drivetrain. I managed to recoup my investment into the Miata completely and then some, and still have parts to sell.
Attachment:
File comment: The Miata shell on it's way out.
Miata Shell.jpg
Miata Shell.jpg [ 470.94 KiB | Viewed 1090 times ]


My new plan is to use the Mitsubishi 4G63 Turbo motor from a first generation DSM in a front-engine, rear-wheel drive setup. Thanks to Bill Hincher in Toledo, Ohio, I got a bellhousing made for a Toyota W-series transmission, which I sourced from a 1992 pickup. He makes a variety of adapters for different transmissions. My goal was a T-56 but I couldn't find one that I could afford, so the Toyota proved to be the smart choice.
Attachment:
File comment: W-55 with custom bell housing
Toyota Trans.jpg
Toyota Trans.jpg [ 554.47 KiB | Viewed 1090 times ]


The search for a differential was quite easy. A 1992 Eclipse GSX gave up its rear differential. I lucked out, having found a four-bolt differential, with a 3.454 ratio and viscous limited slip, which is the strong diff in those cars, and has the perfect ratio for my setup. The scrapyard parted with that for $50 and I was on my way.

My search for an engine has been...less fruitful. I found a complete engine that had been recently machined, and hadn't been put together. I bought the whole thing for $500. It even had some goodies like tubular headers!
Attachment:
File comment: The first 4G on the day I brought it home.
Bad 4G63.jpg
Bad 4G63.jpg [ 504.14 KiB | Viewed 1090 times ]


While waiting to finish my frame, I started purchasing support parts for the engine. I managed to find quite a good deal on a Hallman Boost Controller, Greddy BOV (real, not a knock-off), 14B turbo, socketed ECU, and a complete GSX wiring harness. UNfortunately, I took the engine to a machine shop to be inspected. Trash. Would require about $1000 of machine work to be usable, and even then I would be forced to run a higher bore. :BH: My new plan is, when ready, to find a running front-wheel drive DSM, pull just the motor out, and sell the rolling shell. I'll do a minor refresh and slap it into the car and go. I don't have any intention of modifying the engine, as I am already going to be dealing with quite a bit of power. Rather, I am going to invest my time into very precise tuning to drag as much throttle response and usable power out of the completely stock engine. Estimates from a few people have said I'll be sitting around 290-310 BHP when it is tuned.

Anyway, here is the frame as it sat when I finished welding:
Attachment:
Completed main frame.jpg
Completed main frame.jpg [ 499.37 KiB | Viewed 1090 times ]


Here is a nice picture I snapped of a weld I am really proud of:
Attachment:
Pretty Weld.jpg
Pretty Weld.jpg [ 343.66 KiB | Viewed 1090 times ]


For my first major welding project, I'm pretty proud that this is the only distortion I have in the frame. It's about 1.5-2mm lift in the center of the very back of the frame under the transmission tunnel.
Attachment:
Distortion.jpg
Distortion.jpg [ 385 KiB | Viewed 1090 times ]


And the obligatory Vroom-vroom picture!
Attachment:
Vroom vroom.jpg
Vroom vroom.jpg [ 457.84 KiB | Viewed 1090 times ]


Anyway, I hope I didn't bore you all with this introduction. I am hugely looking forward to this project, and hope you guys find it as exciting as I do! :cheers:

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--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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PostPosted: Wed May 07, 2014 7:43 am 
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Howdy Eric-
Welcome to the forum. Sounds like you're off to a good start. Bummer about that engine block... Could be worse, coulda blown up at the start of the second season... But I digress.

Keep us posted on your progress, pictures are always good. Perry and Bubba don't read too good, they likes pictures! :rofl: Ask questions, show off your work, just enjoy yourself. We'll be here to help or to applaud. (or maybe throw stuff...)

:cheers:
JD Kemp

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PostPosted: Fri May 09, 2014 12:27 am 
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Oooooh, pictures, Perry like pictures! Oooooh and Cap'tn Morgan too!

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PostPosted: Fri May 09, 2014 12:07 pm 
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Dang it Perry, I just spent a whole minute and a half looking for the bottle of rum. .... :rofl:

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PostPosted: Thu May 15, 2014 1:57 pm 
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Location: Boulder, CO
Brief update since it has been a week and a half with no progress. Final exams are over, and summer has officially begun, although issues at work as well as evicting a roommate had briefly put a halt to working on the car. Just for a tiny bit of work, I'm going to at least install the new clutch fork and pivot ball into the transmission, and hopefully move it to my parents house where the frame is.

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--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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PostPosted: Tue Jun 03, 2014 5:02 pm 
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Location: Boulder, CO
Update time:

Sorry it has been a bit, I've been really busy with work. However, I DO have progress to report. What a concept! As of three days ago, the transmission is sitting in the frame, as well as the mock up 4G63 motor. And for the most part, it fits!

Attachment:
Engine test fit 1.jpg
Engine test fit 1.jpg [ 549.59 KiB | Viewed 783 times ]


There is more than adequate room on the turbo side, as well as behind the valve cover. I am slightly worried about the front because I don't have a radiator yet, but I'm pretty sure there will be enough room. The issue I am running into is the intake manifold. As you can see:

Attachment:
Intake clearance issue.jpg
Intake clearance issue.jpg [ 365.44 KiB | Viewed 783 times ]


There is a brace directly in the way of the manifold. What I'm asking you all is this: is that brace necessary? I autocross with a guy who built a Locost and he said he just totally deleted that tube and hasn't had issues. Alternatively, I was thinking of replacing it with a downwards-diagonal brace, sort of like this:

Attachment:
Frame adjustment 1.jpg
Frame adjustment 1.jpg [ 522.94 KiB | Viewed 783 times ]


And then maybe adding a piece from the top rail to the middle of the new piece. Good idea? Bad idea? Let me know what you think!

Thanks!

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--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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PostPosted: Tue Jun 03, 2014 5:19 pm 
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That brace (on the offside in a book frame) ran right through my distributor and oil filter. I moved it farther out where it hits the firewall. It's not doing as much good there, but better than nothing. What about adding a similar brace on the exhaust side?


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PostPosted: Tue Jun 03, 2014 6:33 pm 
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It is there for chassis rigidity. A good thing to have. You can:

1) move the firewall end outward and add a "y" brace
2) move it to the opposite side
3) if none of that works for you, move the front out to the closest you can get to the front "V brace and forget it, or add another mirror image as far forward as you can get. Something is better than nothing. And 2 somethings are better still. That is what I did. Had I known about option 1 at the time, I would have done that on the RH side. The LH side just could not go any further forward due to the alternator and oil filter pedestal.
Attachment:
brace.jpg
brace.jpg [ 8.4 KiB | Viewed 769 times ]

Image

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PostPosted: Tue Jun 03, 2014 7:22 pm 
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rx7locost wrote:
Image



I just love the look of a rotary in that chassis.

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PostPosted: Wed Jun 04, 2014 12:13 pm 
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Location: Boulder, CO
Nick:
The problem I have with pushing the firewall end farther out is I am worried it will be in the way of my steering, which I have yet to position. Although next time I look at the chassis I will look into moving the brace to the other side. I'm just so attached to how much space there is on the turbo side because I have so much stuff to fit around there.

Carguy:
I might imitate the setup that you have, as that will leave me enough room for my steering and all the ducting off the turbo on the other side. And yes, that rotary does look really good in there!

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--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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PostPosted: Wed Jun 04, 2014 12:25 pm 
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One last thought, Don't discount the possibility of making that a bolt-in brace. That way you could have clearance for working on and around the engine when you need to.

P.S. Thanks for the props on the rotary engine. :cheers:

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“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Wed Jun 11, 2014 2:39 pm 
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Right. So, I have fixed my intake manifold problem. I took out the long driver's side diagonal brace and instead went with two smaller braces on each side. I'm really happy with how it turned out. I also had the opportunity at Cars and Coffee this past weekend to examine the frame of a mid-2000's Caterham, and saw that they don't even use those diagonal braces, nor do they have a bar running above the transmission between the two foot wells. I took a picture of the Caterham, and I can pull the pictures off my phone if anyone is interested.

Attachment:
new engine bay brace.jpg
new engine bay brace.jpg [ 555.34 KiB | Viewed 637 times ]

_________________
--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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PostPosted: Thu Aug 28, 2014 4:23 pm 
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Sorry guys, things got crazy at the end of summer. Just started a new machining program at school, and this is what my classroom looks like:

Attachment:
File comment: Machine shop at my community college
Machine shop.jpg
Machine shop.jpg [ 326.27 KiB | Viewed 471 times ]


This is all brand new equipment in a new 11,000 square foot shop. As I study the different machines I will get access to use them for my own projects, as long as I supply my own stock.

I have also moved houses, so that took up a significant amount of my time, though the Lotus is still at my parent's house about twenty minutes away. I haven't touched it in a while, so unfortunately there is a lot of stuff piled on it right now. However this weekend I am house sitting for them so I will have two straight days to work on it. I sat down with a friend to start figuring out my suspension, and this is what we have come up with so far on VSusp: http://vsusp.com/?tool=2d#0.8%26project ... enter.y%7D

What do you guys think? Can someone verify that those are the right dimensions for the Miata hubs?

I also don't have a good way of figuring out caster, wheel rate, spring rate, etc. I am intending to do a pushrod setup and don't really know where to start.

I did find these at my old job, and my boss said I could have them off a Yamaha Vmax snowmobile:

Attachment:
File comment: Remote-reservoir Ohlins coilovers from a snow mobile
Ohlins.jpg
Ohlins.jpg [ 558.38 KiB | Viewed 471 times ]


Think those will work? I don't know anything about them.

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--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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PostPosted: Thu Aug 28, 2014 5:23 pm 
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Eric,
snowmobiles are lightly loaded on the front end. When I looked into snowmobile shocks, most had a spring rate of 120 to 150 lb/in. I need about 175 for the solid rear axle, and around 300 for my light front end. Now spring rate is not wheel rate, and I won't go into it here, but I doubt that such a low spring rate would work.

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PostPosted: Thu Aug 28, 2014 5:27 pm 
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I was thinking it would be possible to get heavier springs for it, I may pick them up just because they are free, but I assumed if I set my bellcrank up properly I could make those work, but correct me if I am wrong!

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--Eric

"Stuckness shouldn't be avoided. It's the psychic predecessor of all real understanding." --Robert Pirsig

Green 1997 BMW 328i (DD)
Red 1989 BMW 325is (No engine)
About a third of a Haynes Roadster


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