Bryan's GT-forty build

Bryan Koehler

Supporter
I purchased a Gt forte laser flat pack at the end of 2017. after looking over what i recieved and the instructions Darrin George sent me i began the journey to build my GT-40. I've decided to start a thread here to gather as much help and advice as i can. my first role of buisness to do was create a good table to build on. i designed my table to not only construct my gt-40 on, but also to build a airplane i have plans for in the future some time after my 40 is complete.
 

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Bryan Koehler

Supporter
And here are a few more which bring me to my current state of progress.20180915_123545.jpg
 

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NickD

Supporter
Hi Bryan. That takes me back a few years. I think it was the most enjoyable part of the build to date. ;-) Keep the pics coming.
 

Bryan Koehler

Supporter
Thanks nick , I bet it does. Im actually working on the middle section now. Im following your build in the order of how you assembled the sections together. Although i weld out the entire frame each time i add to it and grind the bottom flush each time. So far its staying pretty flat.
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just takin it slow.​
 

Charlie M

Supporter
Looks good Bryan.

What did you use for your table top? Is that laminate countertop? How's it working for you?

I bought the same chassis kit early this year but I haven't started the build yet. The build table is the first order of business and I haven't decided what to do yet. Mine is most likely going to be a one-time use so I didn't want to get too elaborate with it but at the same time, I want the chassis to come out flat.

Thanks for posting, please keep the updates coming.

Charlie
 

Bryan Koehler

Supporter
Hey charlie i used 2x6 for the frame with 2x12 at one end which is actually the middle of the table. Below the table is storage and im using 3/8 ply there. The top is two layers 1 layer of MDF 4x8 and then melamine 4x8 both are 3/4 inch thick if i remember right. If i did it over i would just use 3/4 inch plywood. Theres a spot where the 8 foot sheet ends and a 4 foot section begins, that has a slight low spot. I will eventually fix that but i just build on the 8 foot section when fitting up. This tables overall length will be 24 foot for a wing i will build one day. And the L shape is cause i didnt want to cut these sheets so i can use them for the second table later down the road. After the chassis is done i will dissasemble the table and move it back to my other shop , 2hrs away. R u n the USA? And did your kit come complete? If your looking for a cheap solution i would buy 3/4 ply finished on both sides. And clamp angle iron under it to keep it flat . And just check it with a straight edge.
 
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Charlie M

Supporter
Hi Bryan,

Thanks for the info.

Yes, I'm in the US in southeastern MA. No, the kit didn't come complete, I'm missing several parts which I'm still trying to get.

Charlie
 

Bryan Koehler

Supporter
I welded up the middle rail section some time back in january. Then i had to take a break from the build to remodel the house. Hopefully i will get back to working on the 40 over the summer. No other real progress at this time. I did buy a Tig for Christmas but its still in the bag havent even pluged it in yet to see if its going to work. Gota get back to building. Will post new pics as soon as i make somemore progress
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Bryan Koehler

Supporter
Made a mistake or two and had to cut and reposition a few of the tubes. Guess thats what i get for getting in a hurry. I mocked up the middle section and most of the vertical tubes that attach the two together. Everything jiged up good so hopefully this weekend i will be able to do some welding. Ive been searching for a source for 40mm sq tube. Its hard to find and expensive when i do find it. If you know of a good fairly priced source do let me know. I will eventually have to bite the bullit and order it so i can move on. I also am wondering what others are using for round tubing when fabricating A Arms and rear links. I was thinking 1.125 Dom with a .125 sidewall thickness. Or 1" chromoly with .083 wall. Let me know what some of you are using. And if someone has the full dimensions for the rear upright pm me i have a partial drawing of it and need a little more info.
 

NickD

Supporter
Looking good there Bryan. Takes me back to 2014 when I was going through exactly the same process. Made a few mistakes here and there but its relatively easy to remedy. You shouldn't have too many issues getting the whole chassis complete from where you are now.

Planning a massive weekend on my build as I need ti get her finished by xmas allowing me time to get the paint etc. complete before were off to the LeMans classic next July.

Nick.
 

Bryan Koehler

Supporter
Joined my two sub assemblys together and i added the four front post although i havent took a picture of that yet. Everything is still straight and true. Within 1mm. Hope to have some more photos soon.
 

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Bryan Koehler

Supporter
Made a little progress on presidents day. Welded out the main structure. Got some grinding to do now. Welded the dash frame up, and cleaned and etch primed all the tubes for the horse shoe. Primed the tranny mounts and captured nuts. And welded out the tubing for the transaxle to sit on. I originally was going to use a 01e trans but now im thinking i might want to use a porsche box instead. Im scared if i build a 351 to a 408 i will break the Audi box. Just dont know how much it will change the design of the rear chassis if i go with a 930 or g50 box. Any advice out there? I need to make a decision soon. Here state side the price is not too far apart. As there are no audi boxs here unless i get a rebuilt one. So thats 4 to 4500 dollars and i have found the 4 spd 930 box for that price the g 50 is a little more...
 

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Terry Oxandale

Skinny Man
Hope I'm correct on this, but the 930 inverted easily allows a dry sump with good engine/transaxle ground clearance, plus the shift pattern is the normal "H" (using shift rod rather than cables). I think the G50 changes the pattern or reverses it. Shifting takes a little bit of care, especially of oil is cold. I run a modified LS2 with sticky 335's on the back, and have never had an issue. Lastly, I don't know if there is a 930 out there that won't need to be rebuilt, so that will just about double the cost of the box.
 

Terry Oxandale

Skinny Man
930. I paid about 3K for it about 5 years ago, spent another 3.5K for a G-Box rebuild, and some minor "inverted" mods for oil cooler/plugs, and that was it. The synchro design is to me the only detractor for this box. Reasonably lightweight, the above attributes, and geared (ratios) well for V8 torque. I did go with a Mitsubishi push-type slave cylinder though rather than the pull-type common with many Porsche conversions.
 
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