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Learning how to build Lotus Seven replicas...together!
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PostPosted: January 25, 2017, 4:26 pm 
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My dad and I are making instructional build guide videos for the Goblin. They aren't standard build log videos since they are meant to be instructional but I thought you guys might still like them. So far we've made it through stripping the donor, adapting the wiring harness and getting the engine installed and running.

Here's the full playlist for anyone interested in watching them: DF Goblin Build Guide Playlist

The videos of stripping the donor car are interesting, the wiring videos are boring (but they are very helpful) and the actual build videos are fun.

Here are some of the more interesting videos:

Dropping the Powertrain: http://www.youtube.com/watch?v=zxu82X0DJYc

Steering, Pedal Box & Brake Lines: http://www.youtube.com/watch?v=KwtwNNwgECo

Powertrain and Fuse Box: http://www.youtube.com/watch?v=SP30M5DU9Gw

First Start: http://www.youtube.com/watch?v=20PFCjBgMLI

Just in case you don't want to watch the videos, I'll include a rundown of the build below.


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PostPosted: January 25, 2017, 4:34 pm 
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Stripping the Donor Car
The donor is a base model 2010 Chevrolet Cobalt with ~46,000 miles. It is an automatic with a 2.2 liter Ecotec that puts out 155hp. We bought it from copart.com for $1,009.97.

Image

We gutted the donor car. Here's a summary of the pieces we removed that will be reused:
    - powertrain
    - front suspension
    - front brakes
    - master cylinder and reservoir
    - brake booster
    - all of the wiring
    - EPS
    - steering rack
    - seats
    - fuel pump
    - pedal box
    - gear selector

There is more than that but these are the main items.

Image

We cleaned and painted the parts we'd be reusing. We had good luck cleaning with a pressure washer filled with Super Clean. We just rattle canned the donor parts with Rustoleum.

Image


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PostPosted: January 25, 2017, 4:46 pm 
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The Wiring Harness
There are a lot of extra wires in the harness that won't be reused (power windows, AC, stereo, airbags, etc).

Here's how the main harness looks straight out of the car:

Image

The first step is to completely unwrap the harness. When its all unwrapped, its a colorful mess:

Image

Then we cut out the unnecessary wires. There's about 15 pounds of wire removed by the time the thinning process is finished. Here's how it looks after thinning it out:

Image

Finally, we merge the dash harness and main harness. During this process, a dozen wires have to be extended because the engine is swapping from the front of the Cobalt to the rear of the Goblin. Here's what it looks like when it is all done and re-wrapped:

Image

At this point, the harness is ready to go into the car but we have a few steps to complete before doing so.


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PostPosted: January 25, 2017, 5:13 pm 
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Stage 1 of the Build
Our kit assembly is split into 3 sections. Stage 1 ends with the engine in the frame and running.

We started by installing the sheet metal and frame rail hoses.

Image

Next up were the front end parts. The donor steering rack, pedal box, brake booster, master cylinder and steering column all bolted in. Then we ran the wiring harness through the tunnel and up to the dash. We also installed the radiator and connect all of the front hoses.

Image

Image

We installed the power train by lifting the frame up and over it.

Image

Finally, we got the engine cranked up for the first time since taking it out of the donor.

Image

First Crank Video

We haven't started on the next stage of assembly yet. I'll keep you guys updated as we progress instead of just dumping it all on you at one time.


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PostPosted: January 25, 2017, 6:59 pm 
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Interesting. Looks like a well-thought-out kit. Thanks for sharing.


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PostPosted: January 25, 2017, 7:02 pm 
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Two comments:

1. Oh what a luxury to have so much space to work in.
2. It's like travelling 99 miles on a bus for what could have been a 100 mile hike through the mountains. Fast yes, enjoyable, for some, epic memories of the adventure, meh. I know it's not for everyone, but I enjoy the adventure probably more than the destination, which is just icing on the cake.

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PostPosted: January 25, 2017, 7:26 pm 
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I think you have a couple of mistakes in your frame. It's weak at the bulkhead behind the driver for vertical loads, it's own weight. If you look at it like a beam carrying it's own weight, it's strength is mostly just the upper rail. There are different things you can do to fix that. Usually the bottom rail rises up and connects to where the rear suspension springs connect to the upper rail, for example. Or the diagonals that go from the rear upper rail down to the main upper rail near the drivers elbows could be supported somehow, for instance the diagonal near the drivers hip could become an upside down "V" shape and provide support for that brace from the roll hoop.

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PostPosted: January 25, 2017, 11:28 pm 
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I've said it before and I'll said it again: I like what you guys are doing. Keep up the good work! I think you've made an excellent balance of simple/cost/function to interest a decent sized market.

You guys probably already do, but it would be wise to offer completed wire harnesses for clients. Many people are scared of wiring, no matter how simple you make it.

Cheers.

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PostPosted: January 26, 2017, 1:16 am 
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The voice of reason
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Quote:
I've said it before and I'll said it again: I like what you guys are doing. Keep up the good work!


By all accounts the goblins are a nice pair of guys and they have never made an obnoxious post here or been offensive etc. And I'm sorry if I seem a little short here.

I think folks should load test there frames, especially if they are for sale. This is required some places. With 2 200 lb. passengers and a 3 g vertical load that's 1200 lbs., plus some more for the engine and drivetrain. That's a bit sobering, easily 1500 lbs., I think the upper rails will complain about that.

Imagine being hit from behind, which has happened to at least a couple of our members. As the force is applied to the rear, the roll bar braces will push down on the upper rail, but the rail is not supported there. So this frame is not much stronger than the upper rail. It may fold there.

I'm sorry if this is upsetting or discouraging or whatever for these folks, but it is probably possible to fix this. I'm not sure keeping my mouth shut is the right thing to do here. I probably spent nearly a 1000 hours designing the Car9 frame and this stuff kind of jumps out at me now.

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PostPosted: January 26, 2017, 8:55 am 
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We are Slotus!
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horizenjob wrote:
I think you have a couple of mistakes in your frame. It's weak at the bulkhead behind the driver for vertical loads, it's own weight. If you look at it like a beam carrying it's own weight, it's strength is mostly just the upper rail. There are different things you can do to fix that. Usually the bottom rail rises up and connects to where the rear suspension springs connect to the upper rail, for example. Or the diagonals that go from the rear upper rail down to the main upper rail near the drivers elbows could be supported somehow, for instance the diagonal near the drivers hip could become an upside down "V" shape and provide support for that brace from the roll hoop.
Yo, Marcus!
First of all, I ain't arguing, just asking... OK? 8)

I'm struggling to see the weak spots you talk about. It looks to me like the diagonals near/at the driver's hip level do form an upside down V. Don't they? I do notice numerous places where diagonals attach "near" but not "at" the intersection of verticals with the frame rails. That hip area your mention is one of them. That looks a bit odd to me, seems like it would be less effective, but again, "I ain't no enga-neer."

For my understanding, and perhaps to help the DF guys see what you're referring to, could ya maybe do some circles and arrows on the picture of the frame? 'Splain it to us, Bro!

:cheers:
JDK

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PostPosted: January 26, 2017, 9:34 am 
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JD
Take a look at the top pic of the frame.
At the very top you can see the forward facing roll bar support come in contact with the top frame rail right at the bend to make it wider at the hips. There isn't a support node anywhere near that area. Putting a load on an already deformed point, no bueno.

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OOPS I did it again
http://www.locostusa.com/forums/viewtopic.php?f=35&t=17496

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http://www.locostusa.com/forums/viewtopic.php?f=35&t=15216


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PostPosted: January 26, 2017, 11:07 am 
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horizenjob wrote:
I think you have a couple of mistakes in your frame. It's weak at the bulkhead behind the driver for vertical loads, it's own weight. If you look at it like a beam carrying it's own weight, it's strength is mostly just the upper rail. There are different things you can do to fix that. Usually the bottom rail rises up and connects to where the rear suspension springs connect to the upper rail, for example. Or the diagonals that go from the rear upper rail down to the main upper rail near the drivers elbows could be supported somehow, for instance the diagonal near the drivers hip could become an upside down "V" shape and provide support for that brace from the roll hoop.


I'd recommend that you (Goblin folks) don't simply disregard Horizenjob's comment as some crackpot who builds a car in a garage (like me), doesn't know what he's talking about, and is simply looking for faults.

There are some certain styling issues I don't like about the car, rear shocks, but commend what you guys are doing, I think its awesome! Good luck, hope the business is a huge success as I'd love to see more offerings like this in North America.

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Last edited by Trochu on January 26, 2017, 12:28 pm, edited 1 time in total.

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PostPosted: January 26, 2017, 11:09 am 
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We are Slotus!
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Yo, Busy!
Yes, I see that one now... Missed it before... And I see your point.
Thanks-
JDK

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"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom


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PostPosted: January 26, 2017, 12:14 pm 
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Joined: September 22, 2005, 10:29 am
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Could things be better? Undoubtedly. But it's still a hell of a lot more beefy than most Locost frames. Please keep showing us your stuff, and don't pay too much heed to the peanut gallery.


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PostPosted: January 26, 2017, 1:25 pm 
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Here's a picture. The problem area which is carrying a high load in bending is in the green circle. It is being supported by the roll brace which itself is not supported but bending a tube in mid-span. That is what the red arrow points at. You could fix this with either tubes like the yellow tube or the red tubes or perhaps other ways. The yellow tube could be done differently to join up with the subframe mount, but still a similar idea.

I think the goblins are trying to do a good job and the videos are nice. This is a small change in the frame but I think they have left %90 of their strength on the table. Maybe we need a thread that is not so particular to this car but would walk thru how to look at this in a program like Grape. Software to study this stuff is free, but it takes a little effort to learn.

Kreb, you should be careful in your statements. Achilles was only as strong as his weakest point. I will just say I disagree with you... If you were correct I would never have brought this up.


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GoblinFix2.jpg
GoblinFix2.jpg [ 328.74 KiB | Viewed 619 times ]

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SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.
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