"Mechanix Menace": An LS7-motivated, chopped and heavily modified 1973 Datsun 240Z

[chevyz240]

You sir, are my spirit animal lol! I don't know much about SEMA, but perhaps you should see if anyone knows how to get a booth, because your project was already over the top and 3d printing the buck would be so amazing -I think you'd steal the show.

Creality has the CR-30 on Kickstarter still for like 550$, it's a continuous conveyor belt 3d printer that can print infinitely long objects. I know it's not available yet, but perhaps it would save you a lot of gluing if you could print in long strips. Joel over on 3DPrinting Nerd has printed several very large swords and such to prove out its capabilities.

You may also look into an ultra-large 2mm nozzle (in lieu of the stock 0.4). This would help cut down your print time a lot, especially if you're going to hit them body filler afterwards.

Also, Teaching Tech has published a mostly automated version of calibrating your Creality in order to get excellent accuracy of hole locations wall thickness..etc. He published here: https://teachingtechyt.github.io/cal...on.html#esteps and stored the code on Github.

You may already know this stuff, if so maybe it'll help someone else following in your footsteps in a few years. Go get em bud!

Thank you very much jetmech442, both for the nice words and the tips!

I work at Öhlins Racing, and I have been to both the PRI and SEMA shows, working in our booth and holding a couple of shock absorber seminars. Many years back, we actually discussed having my car in the booth! I will of course use Öhlins shocks on it! I don't think this will happen, but a dream would be to have the car in our SEMA booth and then be chosen to compete in the optima Ultimate Street Car Invitational! After that, a month (or 2 or 3) long road trip over the USA would be the finishing touch!

With a larger nozzle, The walls will be thicker, costing more material. I think maybe a 0.8mm nozzle could be the sweet spot. When the CR-30 has been on the market a while and has been reviewed a few times, I will look into that as an option. I actually think that the lengthy print time is not all that bad as if I plan wisely, I can do a lot of other stuff on the car in parallel.

It's going ta take at least a year before I will start printing buck pieces, and with the quick development of printer technology, maybe even better printers will have come out then!

Right now, I'm printing a new test piece, which will be posted here and on https://www.facebook.com/MechanixMenace in the very near future!

[chevyz240]

I am continuing to experiment with 3D printing pieces that will simulate the bucks I will create later for the fiber glass body parts. This is a headlight bucket in half scale. I have taken that from my Blender 3D model of the entire car. It's still a bit rough around the edges, but for this test it works fine! I am pretty happy with the outcome!
I am using high quality filaments from add:north, which is a pretty new Swedish manufacturer. It feels good to support domestic companies, and it feels even better when the product is actually made here! They have a very good web site, where you get lots of info on the different filaments, you get "cheat sheets" that tell you what settings to use in your slicer (software that prepares the 3D print file), and you can compare properties between different filaments.

For more pictures, check out https://www.facebook.com/MechanixMenace!

[David Sloan]

Wow!
So much to like about this build!
I don’t know how I missed this!

[andrewb70]

This is outrageous and super ambitious and I totally dig it.

Andrew

[Motown 454]

That's amazing what you can do with these printer.

[chevyz240]

Wow!
So much to like about this build!
I don’t know how I missed this!

Thanks David!

Your Camaro project is pretty sweet too!

- - - Updated - - -

This is outrageous and super ambitious and I totally dig it.

Andrew

Thanks again Andrew!

- - - Updated - - -

That's amazing what you can do with these printer.

Yes, and for pocket change!

[chevyz240]

Since Christmas, I have been spending quite a few hours on the design of the tube chassis for the Z. Now I have finally come far enough that I can contact SFRO and TESTA, the two organizations in Sweden that inspect and approve homebuilt cars. I would like to hear their comments on tube dimensions etc. so I don't build something that they will not approve, come inspection time. Depending on what they say, I will choose one of the two organizations to be the one to inspect my car.

The CAD model is far from done and complete, but I have modeled all the necessary parts to have the discussions with the inspectors. The suspension and a lot of other stuff is modeled very simplified. As the ones of you who have followed my build for a long time know, the roll cage was built many years ago. At that time, I didn't plan on building a full tube chassis. For that reason, some design choices may now seem a little strange, but I think they will be quite OK anyway.

As some of you also know, the windshield frame, the A-pillars, the roof, the side window frames and the C-pillars are welded to the cage. Since the car is so low, I couldn't have a roof diagonal without hitting my head on it, so I opted for a longitudinal tube in the middle of the roof and welding the roof itself to the cage. I think this will probably be both stiffer and stronger.

The passenger compartment doesn't have any triangulation due to the reason that I instead will glue and rivet aluminum sheets on both sides of the tubes, with a stiff foam core between. This sandwich construction will both be stiff and strong, plus it will also act as sound and heat insulation. The open area below the engine and transmission will be covered by a screw-on thicker aluminum sheet. To optimize tube routing and prevent the need for detachable tubes, the engine and tranny will be mounted from below.
The exact positions of the tubes around the front and rear suspension (based on BMW E39) are not yet decided. That will have to wait until I have developed the suspension geometry in a suspension software. I have measured the suspension points manually, but I feel that's not good enough, so the plan is to 3D scan the suspension before starting the geometry development.

Lately, I have almost decided to make a fiberglass body, but I haven't decided if I at first should go with what I have now and just create some simple fiberglass flares, get the car up and running and approved in inspection, and after that create the fiberglass body. We'll see what I will do… At any rate, the steel roof and part of the C-pillars will remain as they are, since they are integral to the car's structural integrity.

For more pictures see: https://www.facebook.com/MechanixMenace.

[TANKMASTERJ]

I go with these what you have and get it roadable faster. Yo can always upgrade. When going the. Other route it always takes more YEARS.
WHAT IF WE DIE BEFORE DRIVING

[chevyz240]

I go with these what you have and get it roadable faster. Yo can always upgrade. When going the. Other route it always takes more YEARS.
WHAT IF WE DIE BEFORE DRIVING

Yup, that's one take on it! On the other hand, it will be more work in total until I get it where I want it to be! I'm swinging back and forth on this one...

[jetmech442]

Either direction you take it'll be inspirational to see it progress. Every time I see one of your posts I re-evaluate what I spend my time on lol.

[chevyz240]

Either direction you take it'll be inspirational to see it progress. Every time I see one of your posts I re-evaluate what I spend my time on lol.

Haha! Thank you very much jetmech442! I wonder a lot of times what I spend my time on!

[chevyz240]

Today I started preparing the car (and the garage) for the tube chassis construction by removing the engine and trans, the front fender, the front suspension and the stand that was holding what was left of the front part of the car, which was only the parts that hold the hood hinges, basically.

Maybe lifting down the entire front suspension by myself wasn't the kindest thing I could do to my back... I realized that when I had kicked away the stand, but then it was too late...

I took the opportunity to mark out the CG for the engine and trans combo. That will come in handy when I calculate the CG of the car.

See more pictures at https://www.facebook.com/MechanixMenace

[David Sloan]

Nice update!
I just love this part of a build,
figuring out how to make everything work together that wasn’t designed to work with each other.
Thanks for sharing!

[chevyz240]

Nice update!
I just love this part of a build,
figuring out how to make everything work together that wasn’t designed to work with each other.
Thanks for sharing!

Thanks David! Hopefully I will start adding stuff to the car, instead of taking away, which has been the case for a loooong time!

[chevyz240]

I have finished the wooden base for the centerline reference for the car. After that, I decided to reevaluate how I should define this centerline.

When I chopped the roof many years ago, I found that the car had been involved in one or more pretty serious crashes. The entire left rear quarter panel was replaced (brazed in place) and the roof had about a hundred small holes drilled in it. As I understand this was a pretty common American method back in the day to make body filler stick better. Nice... In general, there were some pretty thick Bondo layers here and there on the car.

When measuring the body during the chopping process, I found that the car was a bit warped. Depending on what reference points you used, it was twisted either to the left or to the right... When the roof was off, the body was pretty floppy, so I corrected this warp the best I could. I had to compromise and decide which features I thought were the most important regarding straightness. I also decided on what I should use as the car's reference centerline and marked it up on the body and subsequently the roll cage.



Back to today:
Since I more or less have decided to build a fiberglass body, except for the roof, the alignment of the lower part of the body is less important than the roof's. I therefore started to mark the middle point of different roof features; the back corners of the rear side windows, the windshield corners and so on. When doing this, I thought it would be good to also check the horizontal alignment of the car, since this was kind of a compromise as I explained above.

I found that the roof was a bit low on the passenger side. After measuring several points, I took the decision to shim up the passenger side's chassis stands 2 mm, as this would make the roof as horizontal as possible. Again a compromise was necessary as everything still isn't perfectly symmetrical and straight. I also don't think the cars were millimeter perfect from the factory...

I was still a bit surprised that the body seemed so much out of alignment. After some thinking, I thought it might be good to check the accuracy of the laser levels. More on that in an upcoming post...

More pictures at https://www.facebook.com/MechanixMenace!

[chevyz240]

While checking the alignment of the car body on the stands, I came to think about the accuracy of the laser levels. I decided to investigate that thoroughly. As a lot of other stuff, this is of course something I should have done BEFORE I started using the lasers at all, but hindsight is 20/20...

Anywho, I came up with a scheme of marking up the laser lines on the garage walls, floor and roof, and changing the position of the laser 180 degrees and then doing the same again. This way I could see how much they were off. Both lasers were pretty accurate in Y, but not very good in X. The Bosch was also good in Z, but the Limit was a bit worse. This was a pretty annoying discovery as some of the measurements I did while "scanning" the body are a bit off. This is not super critical, but still...

For the 3-cross Limit laser, I still have to measure the accuracy of the horizontal cross, but in order to do that, I will need a large flat horizontal board. That'll be done later.

At least it's good I found this out before starting the build of the tube frame. Now I know how to compensate for the errors, if needed. Where possible, I will use my carpenter's level instead. While checking the lasers, I calibrated the carpenter's level, and it's pretty easy to see if it's off by 0.1 mm per meter. That's good enough for me!

After this little frustrating finding, I rechecked the Y position of my old centerline and found it to be good enough. The points I used as references are sometimes off to the left, and sometimes to the right, but the worst point is off less than 1.5 mm, so that'll do.

Finally, I could screw down the five one-meter steel scales on the wooden base that will make up the centerline. It was a long time coming, but now it's done! That feels nice!

As usual, more pictures at https://www.facebook.com/MechanixMenace!

[chevyz240]

I while ago the inspector from TESTA (one of the organizations in Sweden that inspect and approve homebuilt and highly modified cars) approved my chosen tube dimensions for my tube chassis. Yaaaayyyyyhhh!!!! 🙂 🙂 🙂

After that I have been searching for material. I intended to use 38x2 for the main tubes, but that was impossible to find in the correct material. I decided to use 40x2, which is readily available.

Today, I went on a shopping spree, driving 250 km (155 miles), buying the square tubes from one place and the round tubes from another. Of course, they had to be picked up in style, so I built some stands that I attached to the bed of my pickup truck. It worked fine. The last time I bought tubing was roughly 20 years ago when I bought the chrome moly tubes for the roll cage.

I took the opportunity to organize my material stand and move some stuff out from the garage. I was pretty lucky too, with the tubes butted up against the outside garage wall, I had around 6-7 cm margin too open a cabinet door!

Now, tube welding is not too far away!!!!!!!! 🙂

As always; more pictures at:

https://www.facebook.com/MechanixMenace

[wfo guy]

I was surprised at your choice of truck. I have no idea what's common in your area but I bet a C10 isn't it.

[chevyz240]

I was surprised at your choice of truck. I have no idea what's common in your area but I bet a C10 isn't it.

Of course, it's not super common, but not super rare either. One of Europes biggest car meets for (mostly) classic american cars is held in my home town, Västerås, here in Sweden. It's called Västerås Summer Meet (previously Power Meet). There will usually be between 10.000 and 20.000 cars here, and you would see maybe around 10-20 1960-1966 C10's.

Mine has an all-aluminum L33 engine (truck LS), five speed manual transmission, drop spindles, 4-wheel disc brakes, Öhlins shocks and some other non-stock stuff. In the summer, I use it both to go to car meets (mostly cars & coffee type stuff), hauling stuff, transporting my mountain bike, grocery shopping etc.

[chevyz240]

I have cut open the rockers in order to reach the bottom of the B-pillar tubes, the "main hoop". I have then taken thorough measurements of the position and angle of the tubes, which was difficult when they were hidden. That info has then been used to design the rear floor transverse tube. The next step is to level my milling machine and then use a hole saw to notch the tube ends accordingly. I am getting close to laying the first welds on the car in a few years!

As always: More pictures at https://www.facebook.com/MechanixMenace