Zach Zupancic

Zach Zupancic

Senior Designer, SolidWorks addict, AutoCAD zealot, Cyclist, Shade Tree Mechanic, & moderately tall. 

Diagram of a drunken tailor

There have moments, well days really, that all I could think about was how am I possibly going to be able to do this. I have never done something like this before, contemplated sure, but never actually put pen to paper or cursor through screen. So I started working it out. I did a bit of research, looked at tons of write ups and pictures, and with the help of Martin Cromwell I was able to start the foundation of the project; complete re-wire, re-diagram of the 240z.

March 7th was the beginning; needless to say it was slow to start. The concept was a simple and nearly no frills harness. The best way that I can describe the future of this car comes from a fantastic film called “Two Lane Blacktop.” While my car is in no way ever going to be drag racing, the concept of the car still stands; a track car driven on the street. To best do this you must shave every pound possible; I shouldn't lose anymore weight so it is time for the car to do so. Unfortunately there have been a few laws put in place that really don’t lend to that concept too easily (CA Law requires wipers, turn signals, horn, removable front windshield). This meant that the diagram would have to increase in its amount of circuits; more circuits=more weight. On top of that there is a great love of “the invisible wiring harness.” So the less wires and circuits, the less will be needed to tuck and hide. On top of that I want to remove everything that was controlled by Datsun; in other words I want switches and buttons for everything. Martin came up with a basic outline, and in turn I changed it into something that I could work with quickly and easily.


Martin pointed out that all of my relays do absolutely nothing as I had them wired incorrectly, so I made adjustments.


At this point I was starting to more and more understand what needed to go in, and how each of those parts worked together. I started adding in nearly everything needed so that I could have a complete diagram. I added in gauges, because the stock gauges would be useless after the re-wire; inclusion of a CB radio with a PA to remove the need for a horn, as well as added the ignition circuit.


Then I quickly realized that the coil needed a bit more work done to it due to me now running a 280z electric distributer. Also added in a starter button so that I could actually start the car…


I let this sit for a night, posted on a few forums and finally got a legitimate response as to how I was doing. They made suggestions to add wiring for an electric fuel pump, if wanted, and kill switch, required by SCCA. While lurking on the forum I noticed that they sell a kit to boost the amperage to the running lights stating that the original harness didn’t provide enough and this $50 kit would make things brighter and more visible. So I just added in a relay to the running light relay.


And this is where it is sitting right now. The only thing left to diagram in is the speaker system. I say speaker system because all I really want is a way to run my iPod through two speakers. I don’t want a head unit, just the necessary thing to boost signal going from the iPod to the speakers. I am still doing research on this, and should hopefully find the solution sometime today. Apart from that, the diagram is complete in design.

Once the diagram is finalized, it comes time to start pulling dimensions off of the car so that I can not only hide the harness well, but also to make sure I am running the correct gauge wire for each circuit.Finally after all that work I plan to modify the diagram to show length, gauge, color, and routing for all of the wires so as to make it repeatable.

It seems that the original idea of a simple diagram was stretching the truth quite a bit... anyways here are some fun facts about the diagram as it sits:

-Total number of switches: 14 (16 if you count the brake light and starter button)
-Total number of relays: 11
-Only worked on the diagram in the evening after a few drinks.

-till next time