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

[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/