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

[LS1-IROC]

Awesome work Henrik!

[chevyz240]

Awesome work Henrik!

Thanks, LS1-IROC!

[chevyz240]

Just for fun, I made an ASMR video (I think..) showing my 3D printed shop press handle holders. You've got to stay on top of the current trends! 😊 I experimented a bit with video effects too.

[chevyz240]

In this video, I show all of the steps taken to tack weld a tube attached to the front firewall in place.

Unfortunately my new theme song turned out with audio quality issues. The text is writting by me and the music is AI created. Quite a catchy little tune, if you ask me! The lyrics shouldn't be taken to seriously, but I am pretty happy with that too, considering it took me just a few minutes to write!

[chevyz240]

A couple of more tubes have been tacked in place on the front firewall structure. This progress is more easily noticeable than what I have been working on lately.

More pictures on:

https://www.facebook.com/MechanixMenace/

[chevyz240]

This has nothing to do with Mechanix Menace, but it might be interesting to see what I do to my 1964 C10 as well, perhaps?

After a little over 12 years, I finally have the same rims in the front as I have in the rear!

The reason it took so long is that the bolt pattern on the wheel hubs was not the same as the rims. I actually have a vertical mill, but without a digital display and with sloppy feed screws, I have felt hesitant to re-drill the bolt pattern in it. A while ago, the opportunity to borrow a friend’s vertical mill opened up, so I jumped on that!
A little investigation showed that the wheel centering lip on the wheel hub was larger than the centering hole in the rim. I was lucky to be able to use another friend’s lathe to turn the diameter down (because my lathe has too much runout).

Before I started modifying the wheel hubs, I brought the rims to my job and measured the center hole carefully. Then I calibrated my vernier caliper as well. Apparently, I was a bit optimistic when it came to how tight the fit could be, so after turning the centering lip down, the rims didn't really fit. I sanded the lip down in my own lathe. The runout doesn't matter during hand sanding.

After that it was time to press in the lug bolts. I had drilled the holes on the small side of the recommended range for the hole diameter. When I pressed the first lug bolt in, it required 8 tons of force! I was worried that the entire hub/rotor would break! It didn't, but large chips came out of the contact surface for the rim!
Well, what should I do now??? It would be a lot of work to get another drill and start over! Instead, I put the lug bolts in my lathe and filed down the diameter. After a lot of testing, it finally turned out pretty well. I don't think the chips that came out pose any safety risk. The hub/rotor is thick.
At the same time as I had the tires mounted on the rims, I brought the hubs along. Since I didn't see any signs that the wheel hubs/rotors were balanced, we put one in the balancing machine as well and it had an imbalance of 10 grams. Totally OK on the small diameter!

Before reassembling the wheel hubs/rotors, I performed an extremely thorough cleaning of the hubs and wheel bearings.

Since the new tires have a smaller diameter, I knew that the ground clearance would be lower. I have already had problems with the control arms scraping on speed bumps, for example. Now the clearance for the control arms was 4-5 cm (around 2”) and they scraped on even full-width speed bumps at extremely low speeds!
Luckily, I had found a pair of longer scrapped prototype springs at work with almost the same spring rate just before I went on vacation. After a lot of work and adjustment, it turned out fine! Now the car is probably a little higher at the front than it was before, but I'll probably leave it that way, because now the ground clearance doesn't seem to be such a big problem anymore. Sometime in the future I might raise the entire front suspension to be able to lower the car more! We'll see!

I seem to have managed to get the wheels well centered and balanced, because I don't feel any steering wheel vibrations! In addition, the car feels more comfortable, despite the lower profile tires. Modern tire technology may be doing its job.
Now I think the car will just have to be driven without further work or mods for a while!

One thing that bothers me is that the rear rims are very corroded, so the contrast with the new shiny front ones is very big! I may have to dull the front rims down somehow, even if doesn’t feel good doing it!

All in all, it feels good to have fixed something that has been bugging me for more than 12 years!!!!

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

[jaybee]

Looks good. I can't help noticing the truck seems to have pretty good gaps all over. I mention it because that's always been a challenge with that range of trucks. It's one of the reasons it took them so long to become popular.

[chevyz240]

Looks good. I can't help noticing the truck seems to have pretty good gaps all over. I mention it because that's always been a challenge with that range of trucks. It's one of the reasons it took them so long to become popular.

Thanks, John!

I have welded in new rocker panels and cab corners, and when I did that, I put in some effort to get better gaps. I also cut the bottom of the doors open and rewelded them to make them more flush with the rockers. I modified the rockers to get rid of the pinch weld, so the bottom of them is now more even in height with the bottom of the front fenders and bed sides.

[chevyz240]

Again a post regarding the support vehicle for Mechanix Menace, my 1964 C10.

The rear wheels on the pickup have been too far into the wheel wells, appearance wise. It hasn't looked good. I've always planned to fix it with wheel spacers. Now it has finally happened!

A couple of weeks ago I checked how big the distance was from the tire to the fender edge in the most extreme position when the rear axle has maximum roll. I had to loosen both shock absorbers and a spring to achieve the most extreme position imaginable.
Since the flange on the fender edge is very wide, I planned to cut it down a bit to really get the wheels as far out as possible, to achieve the best look possible.

I then designed a pair of spacers with the right dimensions in regards to thickness, guide diameters, bolt pattern, etc. These were custom ordered from a Swedish company; Spacer.se. He was on vacation, but once he got home from vacation it only took 2 days for me to have them delivered! Fantastic! Plus, the price was really good.

Yesterday I cut off a bit of the fender flange and mounted the spacers and the wheels. I think it turned out really well! In the pictures the difference may not be so clear compared to before, but in real life it makes a big difference! Now the track width is 80 mm (3.15") wider than before.
One disadvantage is that you can't go as far out on the side of a narrow road when you meet a moron in their SUV who is fiddling with their mobile phone or touchscreen and can't stay on their side of the road, which happens way too often...

Today I'm going out for a test drive. I hope the tires don't scrape the fender edges!

Since the last post, I also have polished the rear wheels, and despite the corrosion, they came out fairly OK, at least from a distance of 10 yards!

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

[chevyz240]

Through the years, I have looked at something like 5000 (FIVE THOUSAND) different rims for Mechanix Menace. Nothing has really worked for me; they have either not looked good enough, or they haven't been available in the correct width, color, PCD or ET. Or they have simply been to expensive!

About a week ago, I found a company that makes forged custom rims according to my wish. I have had lengthty conversations with the owner of the company, and so far it looks very promising! The rims are surprisingly affordable. I have started to model a few versions, and right now, the first one is the one I feel is the best. It will be polished and clear coated.

What do you think? Any input is welcome! 🙂

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

[jaybee]

The one with the reliefs on the sides of the spokes seems very cool to me. I don't think I've seen that done before.

[chevyz240]

The one with the reliefs on the sides of the spokes seems very cool to me. I don't think I've seen that done before.

Thanks John!

Yes, I think that design probably is were I will end up, maybe with some small changes.

The I-beam spoke design is actually a pretty common way to make the spokes stiff and light. It is used on many higher end wheels. An even more extreme way to make the wheels light and stiff are to have hollow spokes, like Porsche started using on the 993 Turbo wheels in 1995. Not only were the spokes hollow, but also a section of the outer rim flange!

[badbu68]

They are all pretty wicked, but I like the top design the best.

[chevyz240]

They are all pretty wicked, but I like the top design the best.

Thanks, Badbu68!

Me too!

[chevyz240]

This has nothing to do with Mechanix Menace, instead it has to do with my job as a design engineer at Öhlins.

This is the first OE 4x4 application for us. Hopefully there will be many more in the future! I have done the main part of the design of these shock absorbers. It's pretty cool to see that Roush has focused so much on the suspension in the video. We were not responsible for the springs. Unfortunately the supplier has a pretty ugly end coil spring protector, but I am pretty pleased with the look of the rest of the shocks. It's going to be interesting the see what the reviews will say about the suspension.

[chevyz240]

Well, maybe not quite, but close...

Again, this is not about Mechanix Menace, but it's about front suspension geometry.

When I bought my '64 Chevy C10 pickup 19 years ago, I already had plans to modernize it. Three years later, I bought an '88 pickup with the idea of cutting off the front end of its frame and welding it to the rear of the '64 frame to get power disc brakes and power steering.

Because the newer truck had such rusty parts, I ditched that idea. I did take the 5-speed transmission, though, and got rid of the stock 3-speed gearbox with unsynchronized first gear and broken second gear! It was a bit tricky to drive.

Over the years, I’ve considered all kinds of solutions: a rack-and-pinion from a modern car, maybe an entire front suspension from a newer vehicle, etc. But since I didn’t want to spend too much energy on this truck instead of on Mechanix Menace, I stuck with the original front suspension and steering. I did install drop spindles, power disc brakes, and Öhlins shocks, so it hasn’t been completely stock...

After driving a truck that was heavy to steer at low speeds, had play in the steering, and 6.5 turns lock-to-lock, I finally decided last summer to buy a ready-made kit with a power steering box and adapter plate to save time. Yeah, right...
Originally, the steering shaft in the column is solid and runs in a straight line from the steering box to the wheel, so in a frontal crash, there’s a high risk of getting impaled! To improve safety, I also bought a collapsible steering shaft from another company. Both parts came from major, well-known American companies. The company that makes the steering box is even an OEM supplier to Chevy. You’d think they’d know what they’re doing—but nope...

When I ordered the collapsible shaft, I was skeptical of the design. It’s a round bar with two flats (double D) that slides into a flattened tube. The slightest play on that small diameter results in major play at the steering wheel rim. When it arrived, of course, I was right!
After lots of tinkering and testing different solutions, I flattened the tube even more, which reduced the play, although the tube is so flexible that there’s still some play under greater force. To fix that, I mounted a couple of sturdy flat bars that I can tighten just enough to eliminate the play while still allowing it to collapse in a crash.
Flattening the tube increased lateral play. I solved that with four set screws, adjusted just enough to support the inner part.

One thing I don’t get is how they can sell this part at all! You either have to cut and machine splines into the existing steering shaft, or like I did, turn and mill an adapter to weld on. In the end, it turned out fine!
Now to the steering box itself! You get an adapter plate that you’re supposed to bolt to the frame using two of the original holes from the old box. Then you drill two new ones. The new box is then fastened with three bolts through the frame and a fourth into the adapter plate.
Early on, I saw that things didn’t line up properly. When I mocked up the box, it turned out to be tilted 15 degrees off!!! Plus, the inner tie rod ended up in the wrong spot. When you steer, you get different bump steer on each side. Ackermann geometry is also off, though maybe that’s less critical. At first, I considered installing it as-is. It would work, and maybe you wouldn’t notice much, but I want it right and perfect—so I decided to do it properly, which meant a ton of work!

First, I had to make sure the truck was level side-to-side. I used a cross laser and shimmed the height with cardboard pieces between the jack stands and the frame! Then I had to lie on my back and juggle the 14 pound steering box into place using a stool, wood blocks, ratchet straps, and clamps. After lots of measuring with a laser, tape measure, and angle gauge, I finally got it right.

With the correct placement, I could mount the box using all four bolts through the frame, which makes it sturdier. Why they didn’t do it right from the start, I’ll never understand! I’m going to write to them and ask what they were thinking—if they even were...
Once the box and shaft were in place, it was time for the hoses. The box manufacturer had a kit that was supposed to fit, but I got suspicious when the hose fittings had imperial threads and the box had metric threads... When I emailed them, they said that with exiting thread engagement it would work... Seems pretty sketchy! Especially with hydraulic pressure of at least 1200 psi.

In the end, I had a local shop make hoses with banjo fittings. When I tried to install them, the banjos wouldn’t seat properly. Turned out the banjo bolts bottomed out in the box threads... Oh well, I just turned down the lengths a bit and that solved it!
When everything was finally in place last weekend, I took it out for a test drive. What a difference!!! From 6.5 turns, it’s now 3. Sure, with 10% less max steering angle, but still! The power assist is too strong, so I’ll eventually install a smaller diameter restrictor in the pressure line. Right now, the steering is way too light with too little road feel. But the turn-in feels almost like a race car!

Previously, the slow steering and play made it pretty stable—you could wiggle the wheel a bit without anything happening. Now, with the light and quick steering, even the slightest movement causes a change in direction. Takes some getting used to. A bit heavier steering would probably help.
One thing that became very clear is that the old-school feel is almost completely gone—for better or worse. Now it feels almost like jumping into any modern car, with disc brakes all around, Öhlins shocks, an engine that cruises at 1400 rpm at 60 mph, etc. But overall, it’s a huge improvement—you don’t have to break your arms to park, you can take tight 90-degree turns without driving extremely slow to be able to turn the wheel quickly enough, and you’ll probably be able to catch slides out of roundabouts more easily! More testing to come!

After way more work than expected, I’m actually really happy!

This time there are lots and lots more pictures at https://www.facebook.com/MechanixMenace/

[chevyz240]

A little later than usual, but that is partly due to work that I have done on the C10 that I have shown here. Yesterday I cleaned the garage and put away a lot of tools and stuff that I bought at an auction in September. The garage was then ready for some Mechanix Menace action!

Today I started to seam weld some of the tubing in the firewall area. I then welded in a couple of pieces of sheet metal covering up holes in the old A-pillars. After that I cut out and started to tack in place the driver's side kick panel. Unfortunately, the argon ran out before I was done. Some of the welds didn't really turn out as well as I would like... I think I need to brush up on my welding skills after a long hiatus...

If everything goes as planned, I will have a looong vacation next summer! Starting mid May or at the latest early June and going all the way through September! Verrry niiice, as Borat says!

This has got me thinking... I will not write this is stone, but I think I may be hatching a plan to have a driveable chassis before that vacation ends!!! Everything will be hooked up temporarily and I am happy if it rolls under it's own power! It may even have Flintstone brakes, but as long as I can drive it around the block, I will consider I have achieved that goal!

Getting feedback and response from you guys will inspire me and help me being motivated!

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

[chevyz240]

This fall I have spent a lot of time on the front suspension design, both regarding the geometry and how it attaches to the tube frame. Now I have finally finished this big job! In the video, all of this is explained in detail!

[carbuff]

Thanx for sharing that. Enjoying the build process on this one.

[chevyz240]

Thanx for sharing that. Enjoying the build process on this one.

Thanks, Bryan!