And Yet Another "Home-Brewed" item. 3 Wire Shielded cable.

Dart67 said
In the process of doing my 440/512 engine rebuild and redoing some of the EFI/Coil Near Plug wiring, I need a 6 foot length of 3 wire shielded cable for my cam position sensor.

I thought I had some here. Nope... Needed to get the wiring and harness finished so did not want to order and wait.

SO, I made my own.

I had the correct 3 colored 18 gauge wire.

What could I use for the shield?

Lets see.... Being a Ham Radio operator, I have some short random lengths of RG8 coax laying around.

Found a piece close to the length I needed and stripped off the outer rubber coating and slid the woven copper shield off the center conductor.

Then taped the 3 wires together and pushed them through the salvaged copper shield. Should work better than the minimal shielding that comes on most shielded cable.

View attachment 1716464826

Clever solution to the lack of the cable. I am not being critical, and only trying to provide some additional information regarding shielding and electrical noise. You may have wanted to put a twist in the three conductors before pulling them through the shield. I worked in design, quality, and field service for a major manufacturer of industrial automation, and I was focused on our servo drives and motors. Electrical "noise" was a constant challenge with the high switching frequency of the servos and long cables and auxiliary conductors that run between the drive and motor, and something we extended a lot of effort on. One of the worse things you can do for coupling HF noise injection into a conductor is to run them parallel, with no twist in the conductors. May not be an issue for your application, but the more reliable way to go about it would be to braid the three conductors on a 3-6" twist, then pull them into the shield. You'll also want to limit the amount of unshielded conductors on each end, and route the cable away from any other potential sources like plug wires and or power wiring. If you do have to cross a potential source, arrange the wires at a 90 degree angle to each other. This minimizes noise coupling from source to victim.
Probably more than anyone cares to know, but chasing noise gremlins can be very frustrating. I've spent a good portion of my career on the topic.
This is a link to a document we came up with to help our customers design their servo drive installations with the best chance of success. It isn't all applicable, but a lot of the information can help avoid issues on installation of aftermarket engine controls, A/V units, and ignitions. I worked on some of the tests in Appendix A, and hold a patent related to circular bonding of motor power cables.

https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/gmc-rm001_-en-p.pdf
Again, a clever solution to the problem that very well perform as intended. But it does have some vulnerabilities that may be exposed if something in the system changes or it's tried in another application.