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

[chevyz240]

In preparation for the chassis construction, I first leveled my old vertical mill. This will make it a lot easier to get the correct angles of the tubing notches.

After that I used the info from my CAD model of the chassis to cut and notch the rear floor transverse tube, which is the one most logical to start with. I had to think a few times to make sure that all the angles were correct and pointing in the right direction. To my surprise, I got it right the first time! I just had to sand the notches a little bit to get a nice fit. Not only did it fit well, it ended up perfectly aligned and in the correct position too! I used both lasers to position the tube before tacking it in place.

This feels really nice. Now I have a good base to build from!

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

[chevyz240]

The front end of the rocker panels need to be pie-cut to fit the frame design. Naturally the inner support structure needed a little relocation too. Now one side is almost ready for the square tubing that will be welded to the rockers.

Yesterday I received the digital spirit level I had ordered a while ago. I also bought a used fresh air welding helmet, which will be good for my health. I will also use it as a grinding mask. Right now if I use a dust mask in combination with the reading glasses I now require (I'm getting old...) and protective glasses, the glasses fog up in less than a minute. Hopefully the new welding/grinding helmet will mean that I don't need a common dust mask. I learnt from the guy I bought it from that if you fart when you use it, it will be highly unpleasant... The filter is located right above your butt!

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

[Motown 454]

First that is info (fart ) you’ll definitely be glad he gave you, because it will be your eyes water and you can’t just wipe them clean.
Consider it that first bar will be the beginning of something beautiful. ��

[chevyz240]

First that is info (fart ) you’ll definitely be glad he gave you, because it will be your eyes watering and you can’t just wipe them clean.
Consider it that first bar will be the beginning of something beautiful. ��

Haha, yeah I guess it was a good warning! He also recommended the activated carbon filter. Then you can fart all you want!

Thanks Wayne!

[chevyz240]

After the usual summer break and a fall and early winter full of work insulating the basement and laying down new drain piping plus some repair and maintenance work on my 430 000 km (267.000 mile) daily driver, it was finally time to continue work on Mechanix Menace!

I have swapped from a 20 liter rental Argon welding cylinder to a 10 liter version that I own. In order to fit it to my homemade welding cart, I 3D-printed a couple of adapters. The bottom one got some layer separation, but since it's only loaded in compression, it still works.

After that, I welded up the front side of the the driver's side rocker panel in the same way as the passenger's side. I used the Speedglas fresh-air welding helmet I bought used this summer. I use it for both welding, cutting and grinding. If I had bought something like this 40 years ago, I think my lungs would be in better shape!

The next step was to create the chassis jig for the driver's compartment. It consists of particle board stiffened with 2x4's. I had to shim the 2x4's with thin cardboard to get the surface perfectly flat. In the rear, it's clamped to the transverse tube I welded in earlier in the summer, and in the front it's supported by two wooden legs. It took some filing of those legs to get the jig perfectly level.

Today's last job was to notch the square tube that will be welded to the passenger's side rocker panel and rough cut the joint to the wider rectangular tube at the front of the rocker panel.

Let's hope that 2022 will be more focused on the Z!

Happy New Year!!!!!

As always, more pictures can be seen at https://www.facebook.com/MechanixMenace

[Motown 454]

The progress looks good. Happy New year to you too.

[chevyz240]

The progress looks good. Happy New year to you too.

Thanks Wayne!

[chevyz240]

Today I welded up the combination of square tubes that make up the outer part of the floor on the passenger side and welded them to the rocker panel. I was surprised how little distortion I got!

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

[TANKMASTERJ]

I absolutely love this project. The rendering no is beautiful. As wil be the process of the build.
I'm subscribed
Jason

[chevyz240]

I absolutely love this project. The rendering no is beautiful. As wil be the process of the build.
I'm subscribed
Jason

Thanks Jason! Be sure to check out my Facebook page, there you will found a lot more pictures!

Henrik

[jaybee]

Making progress, and everything looks great.

[chevyz240]

Making progress, and everything looks great.

Thanks John!

[chevyz240]

Last weekend I fabbed and tack welded the square tubing to the driver's side rocker panel. After that it was time to mark out where all the bottom tubes are going to be placed on the floor jig. A couple of different methods were used to make sure the transverse lines are at a perfect right angle to the center line.

I have been feeling a bit ill since Monday, and yesterday I tested postive for Covid. Luckily, it's just like a mild cold (at least so far), so I have been able to continue working on the car.

In order to help positioning the chassis tubes, I 3D printed a clamp for the 40 mm round tubes. I can imagine that I will make other, more intricate, clamps and fixtures when the need arises.

Today I moved the heavy, bulky tubing bender from it's storage in the basement to the garage. It was a bit exciting holding it in place while reaching down tightening the screws that hold it to the garage floor. Luckily it didn't fall over. I then levelled it in both X and Y. It was very long ago since I used it the last time. The dies are made for 1 3/4" tubing, but I have previously made removable aluminum sheet inserts for smaller tube diameters. It works pretty well.

It was then time to bend the first bottom tube for the transmission tunnel. I got the angle perfect on the second attempt. A bit lucky, I guess... The next step was notching it for the rear transverse tube. I did that in two steps, so I could see how much it needed shortening. The final thing today was to make a rough miter cut where it will be joined to the front transverse tube. Tomorrow I will finalize that joint, and hopefully tack those two tubes in place.

It's perfect to have a digital level and a laser when aligning tubes to be cut or notched.









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

[TANKMASTERJ]

Nice bender! And I absolutely love this project. That z is going to be so freaking cool and fast! Keep the good work and updates coming Henrik!
Jasom

[chevyz240]

Nice bender! And I absolutely love this project. That z is going to be so freaking cool and fast! Keep the good work and updates coming Henrik!
Jasom

Thanks Jason!

Yes, it's a pretty good bender. I bought it many years ago in the States on a business trip. In order to get it home, I had to buy a pair of tie-down straps and attach them to the box and wear it as a back back. It weighs around 90 pounds (that's without the stand, which I have made), so it was a bit tricky to put on and off. In conjunction with my other luggage, I think I had 180 pounds of luggage in total! Luckily, in those years the airlines weren't so picky, so I didn't have to pay for overweight baggage.

[chevyz240]

When checking my chassis jig, I found that it needed some tweaking to be perfectly flat at the front end. That was achived by inserting shims made of paper folded different number of times inserted between the supporting 2x4 and the particle board in different places. I also noted that the board sagged a bit in the middle, so an extra supporting 2x4 was screwed in under the centerline and also got shimmed to create a flat, horizontal surface. The entire surface is now flat within 2 or 3 tenths of a millimeter. That is good enough for me.

I have done some experimenting to find out how much to chamfer the tube ends for different junctions to create the best weld penetration. I also tested out what welding current to use for the different junctions.

Now that I have those things sorted out, welding in upcoming tubes will go much quicker. Yesterday, I also 3D printed two new clamps to hold the tubes firmly in place on the jig, to help minimize welding distortion.

Today, the two tubes making up the lower right side of the transmission tunnel and the lower right side of the firewall were tacked in place. I am putting a lot of effort into assuring everything is as spot on dimensionally as humanly possible with the tools at hand. I know that after everything is fully welded, the chassis will distort, but I don't want to add errors already at this stage. I take way to much pride in my work for that. Although this project would move along much, much quicker if my standards were closer to the average gearhead's...

The left hand lower trans tunnel tube also got bent before leaving the garage for good today. Just for fun, I calculated the two tube bends I have made so far are within 0.03 degrees of where they should be. Of course that is impossible to achieve with the tubing bender alone. After using the bender 2-4 times, I need to put the tube back in the bender and then yank on the tube by hand a few times, either in the bend direction, or in the opposite directing, to get it spot on. Since I am using mild steel, as opposed to the chrome moly used in the cage, this demands a bit less effort.







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

[chevyz240]

The last week I have tacked together all the tubes making up the bottom layer of the passenger compartment. It all started a bit bad though: I had bent and notched the driver's side trans tunnel tube, and was just going to make the miter cut at the front end. As always, I measured carefully, but I made a screw-up using the line for the wrong side of the transverse tube... That meant the tube ended up too short... Maybe three hours down the drain! Well, the next day I got back on the horse again and did it correct this time. A bit quicker too, since I had gotten more practice!

After all those tubes were in place, the next thing on the agenda was to start building the upper level of the chassis jig. This will be used to position the tubes for the upper part of the trans tunnel and the upper transverse tube, which also will be the base for the rear end of the chassis. This tube will be welded to my previously hidden B-pillar tubes, so I had to cut part of the inner sheet metal away first.







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

[chevyz240]

I have finished building the rear part of the jig for the upper layer tubes. This is again made of 22 mm particle board and 2x4's. A couple of 2x2's are used to position the rear upper crossmember. Again, the jig is shimmed perfectly flat and horizontal using cardboard as thin as 0.35 mm.

Then it was time to make the rear upper crossmember. It consists of two 50x50x2 square tubes welded together. Ideally, this crossmember should go all the way out to the B-pillars of the rollcage (It could be considered to be the main hoop, but it's actually not ). This is not possible due to the seats being so close to the rear wheels. Instead the crossmember is attached to the B-pillars via 1.5 mm thick Docol 800 sheetmetal pieces.

Initially these pieces were designed to be warped to match the two angles of the crossmember and the B-pillar. I soon realized it was impossible to warp this high strength sheetmetal. Instead I bent it diagonally to match the angles. Of course, I could not use my homemade sheet metal brake due to above reasons, so I clamped if between two 2x4's in my vise and banged on it with a sledge hammer. The result came out OK.

To position this piece, I again used my 3D printer to make a couple of fixtures holding it perfectly perpendicular to the B-pillar tube.







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

[anguilla1980]

I don't use FB so I appreciate the updates you take the time to make here.

Great to see the progress on this. I'm sure there are many like me who can learn from your skills.

[bkbkbk]

Wow, thanks so much for sharing this build! I absolutely love the classic Z cars. Sure wish I had the mind to juggle so many elements of a project as you. I would be completely lost.