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

[rat_rod_russell]

Do you think so, Russell? The downside is that I don't post nearly as many pictures here due to the limited storage and the long time it takes to upload and insert pictures.

Ah, Noted. I didn't realize that.

[chevyz240]

This week, the focus has been on the radiused connection between the wheelwells and the inner wheelwell walls. As I have said before, the shape is kinda strange. I decided to 3D-print pieces that I have used as bucks for forms cast in concrete. These forms are then used as templates and hammer forms. Due to springback of the metal, it's not possible to just beat the sheet metal into the form and it's OK. I put my recently bought sandbag, my shrinker and stretcher and some anvils that I shaped from a piece of railroad rail plus a sledge hammer head to good use too!

Thanks Tobias for the tip of using cling film as a release agent for the 3D-printed buck and also suggesting reinforcing the concrete with steel net.

Since it was quite a long time since I did any serious panel beating, I practiced a couple of times on some scrap metal before starting on the actual pieces.

I will have a small overlap joint between the radius and the wheelwell. This way, I hope to be able to weld it without any filler rod, minimizing distortion. I also get a little margin for using bondo to create the final shape. Since I have this margin, and since I will also upholster the trunk area, I felt OK with the shape not being perfect...







A lot more pictures at https://www.facebook.com/MechanixMenace

[chevyz240]

The inner wheelwall walls got slightly distorted when I tacked them in place. They are supposed to be single curvature (only curved in front and rear view). Now they are also slightly curved in plan view. In order to fix this, I have made a fixture out of particle board that I can clamp on the wheelwell wall to straighten it. Initially I tried to shape it using only a rasp and a plane, but as I guessed, it was too tricky to get the shape perfect. I fixed this by smearing on bondo and shaping it by dragging a steel template along some square tubing guides.

I then attached the fixture to the wheelwell wall, put the wheelwell itself in place and adjusted the angle by using my laser. It was a bit tricky to clamp the radiused sheet metal piece correctly in place, but after a while I managed. I have a small overlap between the pieces, so I should be able to weld them together without filler rod, minimizing distortion. For now I just tacked it in place. I couldn't reach all the way in to the center of the piece with C-clamps or welding pliers, so I had to use a piece of lumber standing on the floor to push it up against the wheelwell.

All in all, everything went way better than I thought!







A lot more pictures at https://www.facebook.com/MechanixMenace

[chevyz240]

This week I have started on the right hand side wheelwell. I started by building the jig for it. When I put the wheelwell in place, things didn't seem right. There was way to big a gap against the inner wheelwell wall. At first, I was afraid that the wheelwell itself was too narrow, but after a while, I found the error. I had measured the transverse (Y) coordinate against the wrong side of the steel rulers on the floor that mark the centerline of the car! Sigh! This meant the wheelwell was spaced out 28 mm too far. Luckily I didn't have to redo the entire wheelwell jig. I just had to modify it. But that still took a couple of hours.

I have also cast the second concrete hammer form for the upper radiused corner on the right hand side. The sheetmetal part itself has also come a little bit on the way. I think this side will be quicker to make, as I now know better how to do it.

I am off from work next week, so hopefully I will make more progress than usual during a normal week.







This week, there is only one more picture at https://www.facebook.com/MechanixMenace

[chevyz240]

I have cast a few more concrete hammer forms and three more radius pieces have been tacked in place. I realized that I need to make all the new pieces half as long as the first ones, since now I can only clamp them in place from one direction. If they are too long, the farthest end can't be reached with a C-clamp or a welding plier.

I have also started tacking the C-pillars to the wheelwells. The game plan here was to make small flanges at the end of the connecting pieces so they could be welded without filler rod, again minimizing distortion. In order to create the flange with the correct radius, I made a hammer form out of a thick piece of flat iron.

Even though I have taken great care, the wheelwells still have become slightly distorted. I think this is due both to welding heat and the clamping of the radius pieces themself. The right hand side got extra distorted. It's nothing that will have any practical influence, nor will it be possible to see with the naked eye, but it still bugs me! I managed to correct the shape reasonably well with some extra fixtures and some hammering.

In retrospect I think it would have been best to have tack welded some sturdy fixtures close to the sheetmetal edges of the wheelwell before putting in the radius pieces. Then these fixtures could have been cut away after fully welding the radiused corners.







A lot more pictures at https://www.facebook.com/MechanixMenace

[David Sloan]

Killer work my friend.
Keep up the great work.

[chevyz240]

Killer work my friend.
Keep up the great work.

Thanks David!

[chevyz240]

This week, not so much has happened. I have cast one more concrete hammer form for the wheelwells. What I HAVE done is looked at possible rims to use. Again... I must have spent hundreds, if not thousends of hours doing this over the years. At one point, I know that I had looked at more than 3000 different wheels. And this was many years ago...

One wheel brand that I didn't know of until a couple of years ago, is Protrack. They are located in Germany, so there is no import tax and the shipping fees compared to from the States will be much lower. They have a model, the Protrack One, that is available in the widths and offsets I need. It is a flow formed wheel that is used a lot in racing. Both the front and rear wheels would have BMW bolt patterns.

For the Corvette front hubs, I can use "wobble lug nuts", that I recently found. I guessed that they existed, but I hadn't actually seen any. Now I know what they look like and how they work. Or, maybe I will redrill the hubs to the BMW bolt pattern. That's probably the best solution. What is good is that the centering holes in the wheels are a bit larger than the Corvette's, so I can use hub centering rings. Unfortunately the BMW E39 rear hub uses a larger hub center diameter than other BMW wheels, so for the rear wheels, I would need to remachine the wheels. But that's doable.

I'm not 100% sure that I think the look of the wheels is good enough, so I will have to let this sink in and see how I feel after having compared them to the alternatives many more times. Regardless of the wheels I will choose, the front wheels will not have the nice concavity that I like, due to the Corvette's high offset. I prefer to stay close to the stock offset for driveability reasons, even though I could find much better looking wheels if I would choose a lower offset.

The wheel on the black car would be my front wheel, and the wheel on the white car would be my rear wheel.

[chevyz240]

Right now I have a cold, so I don't have the energy to work in the garage, and the weekend before I was lazy, so nothing has happened on the project in a while. Also, with summer banging on the door, there will be more outdoor activities from now on. I will try to make sure that the garage activities won't stop altogether, but the pace will definitely be slower.

I have created an Instagram account covering the Z-car project to extend it's reach. 🙂

https://www.instagram.com/mechanix_menace/

In the future, I will be doing all new posts both here, on Facebook and Instagram, so regardless of social media preference, it's easy to follow Mechanix Menace! 🙂

It has taken quite a while to copy everything over to IG. There are currently 405 posts! The limitation of the number of images and characters per post has required a lot of extra work. Not being able to mix image formats in the same post has required an INCREDIBLE amount of extra work! The fact that you get blocked for more than a day if you make too many posts in close succession has also meant that it has taken a long time!

We'll see if it was worth the trouble! 🙂

[chevyz240]

I have a cold and don't have the energy to go down in the garage. Instead, I've created a Youtube video covering the entire Mechanix Menace project from 1988 to the present! 34 years condensed down to 9 minutes and 20 seconds! Almost all the work I have done is documented including CAD models, Photoshop and Blender renderings, 3D scanning and more. Subtitles describe most of the steps. Watching the video is an effective way to digest the whole project in a short amount of time! In addition, some pictures are shown that I have not published on other social media.

It was an awful lot of work, but I'm quite happy with the result!

https://www.youtube.com/watch?v=i-2BIND4f4k

[chevyz240]

Due to the nice weather I haven't done anything on the car in a while. However, I have kept googling possible rim choices (which I do a lot). I have found some rims that's been on the market for a few years, but I don't think I have seen them before. They are called Rennen FT10. I like them a lot. They are available in 19x10" and 19x12" dimensions. Initially I planned on using 9" front rims with 255 tires, and 11" rear rims with 305 tires.

Incidentally, at the same time I found these rims, I read an article where Tire Rack tested different width tires on different width rims. The combinations with the widest rims were always the quickest on track. These combinations had slightly wider rims than what the normal suggestion is for that specific tire width.

I realize that this may not always be the case, but at least I don't think I will lose much performance with a slighty wider rim than recommended. There are some other benefits too; the concavity gets bigger for the same offset, the tire shoulder gets more rounded, which increases the margin to the fender lip when turning, compared to a more square shape.

The price is fairly reasonable, and I like the color options. I don't have to order any expensive custom color. They are flowformed, so hopefully they aren't too heavy.

If anybody has any experience with these rims, please let me know!

At least it's good to have yet another option! ��

[chevyz240]

As I have previously written, there isn't too much activity in the garage during the summer, but at least a little has happened. Yesterday I tack welded yet another wheelwell radius piece in place. In order too reach in far enough to clamp it in place, I made a custom C-clamp from some bar stock and a couple of screws.

Today, I also cast yet another concrete hammer form.









A few more pictures at https://www.facebook.com/MechanixMenace

[Pedigry]

I'm exhausted just looking at the pictures. Unbelievable amount of work. Amazing...

[chevyz240]

I'm exhausted just looking at the pictures. Unbelievable amount of work. Amazing...

Thanks Pedigry! Sometimes I wonder if it's worth all the work... But it keeps me off the streets!

[chevyz240]

It took a bit longer than planned (as always), but today I have started to work on Mechanix Menace again after the summer break! I spent maybe two hours in the garage cutting and hammering a piece of sheet metal for the right hand side wheelwell radius. I hope that it won't take too long before I can go on to new projects. This is starting to get a bit old...

[chevyz240]

This week, I have made some further progress on the rear wheelwells.

Since I have decided on making a fiberglass body, I will now modify my Blender 3D-model to get the look I am after. This will mean widening the entire body, not just slamming on some fender flares. I have found a new Blender course that promises to teach some very cool tricks to simply modeling and to help get much better end results. I have purchased it, and started looking through some of the sections. In the course, I also learn that the latest version of Blender has a lot of new functions that will make things a lot easier and better. I am looking forward to start modeling again! 🙂

[chevyz240]

The cutouts for the seatback/rear fire wall have been closed up. I tacked in a temporary upper firewall crossmember to use as a guide for the slope of the cutouts. On the driver's side, I have also tacked the wheelwell to the quarter panel inner sheetmetal structure. It's quite satisfying to see those holes being covered!







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

[chevyz240]

The passenger side wheelwell has now been finished regarding tacking it to the quarter panel inner sheet metal structure. One picture shows the bottom sheet metal piece, which is the most complicated one. It connects the wheelwell, the B-pillar tube (main hoop almost) and the inner structure. In order to get this piece to fit, it needs all four sides to have the correct length and angle, the bend angle needs to be correct, and the sides connecting to the round tube and wheelwell need to have the correct curvature. It's a lot of trial and error, but it's tricky pieces like these I really enjoy making (as long as I don't have to make to many of them)!

I have also cut away the remains of the driver's side quarter panel and the B-pillar. The fiberglass body will go all the way up to the quarter window. Before I cut away the sheet metal, I measured the height on some control points along the quarter window to see if there was any change in shape after the cutting. I didn't think so, as it is a fairly stiff area, but I wanted to be sure. Everything stayed in place.

In the future, I will create a sheet metal structure that will connect further out on the wheelwell, to stiffen this part of the body/chassis, and also to act as a side impact deformation zone. Before I can do this, I need to finalize the body shape, so this will take some time.







A lot more pictures at https://www.facebook.com/MechanixMenace

[chevyz240]

This week I have reacquainted myself with Blender and started the body design work. As I have previously described, my plan is to widen the entire body and keep much of the Z-car DNA, but make the car lower, wider and cooler! 🙂

At this stage, the model is VERY rough with lots errors and lots of stuff missing. The plan is to make a number of versions and decide which one to go with before starting the work of refining everything.

One thing that has made me feel uneasy for a very long time, is the shape of the rear part of the hood. Stock, the car has a pair of ugly inspection lids beside the rear of the hood. In order to get the wipers to sweep the entire windshield, I needed to incorporate those hatches with the hood. For those of you who haven't followed the entire project, the car has hidden wipers and I open the hood a bit to reveal them when the wipers are turned on. This gives an ugly look to the hood.

I wondered if a wedge shaped hood would look worse than a straight hood, so I decided to model it and see if that shape was acceptable. To my joy, I think it actually looks much better! Problem solved! With the widened body, I think the front fenders look to wide from above with a straight hood.

The hours really fly when I'm modeling, but I really enjoy this kind of work! I need to divide my time between physical work on the car and digital modeling! 🙂







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

[chevyz240]

The last couple of weeks I have continued the modeling in Blender. I tried out a rear spoiler, but I feel that it hides the lines of the haunches, which are clean lines that I really like. After that I made a wing, which I think is the way I will go. Maybe I don't have to decide now, as the attachment points probably can be made to work with either a spoiler or a wing.

I also checked front fender clearance to the tires at full lock and full compression, and as I was afraid, the 255/35-19 tires hit. I have already raised the top of the front fenders, and I feel that the looks will deteriorate if I raise them further. I really don't want to go to lower aspect tires due to grip, comfort and damage risk reasons, but I think I need to go to a 255/30-19 tire instead. I will model that in the near future.

As before, there are lots of flaws, misses, stuff that is missing in the model, but I am still at the rough modeling stage, to get a general feel for the shape. So far, I am pretty pleased and excited! 🙂
One good thing is that there is plenty of clearance between the engine and the hood. Maybe I will try out a lower hood line to see how that looks.







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