Engine Bay Harness from scratch ... I'm planning to build it ...

[280z1975]

Ok, a little update ...

So after some searching, a lot of reading and some serious thinking about this project I am going to make this happen ... how is the real question.

One great read if your interested is this thread:

http://www.classiczcars.com/forums/showthread.php?t=10416&highlight=harness

The thread is by ZHadMan, Keith Hadley. He to seems to have attempted this, but it never went through all the way. If you have his e-mail please PM me. I sent him a PM, but his last activity here was well over a month ago.

I've contacted Victor Laury who has been nice enough to help me identify the connections for the wiring harness. As per the other thread the connections are Fastin-Faston connectors used by Nissan in either the 6.35 [.250] or 2.79 [.110] series (spade terminal width).

The engine bay harness is the one I will focus on at the moment. I will be making a template for the stock 280z and then going over to the stock 240z. It will take some time to figure out everything, but I am sure it will all come in time. The engine bay harness is much simpler when it comes to connectors than the rest of the system, so this is why it is my first focus.

If there are connectors we can't find I am looking at reproducing them using silicone molds (or metal molds if we need a lot of them). I have already sourced the distributors of the products i need to do this and have even found a local shop that does lots of plastic mold work only a couple of miles down the road. (I am sure there are others, it's very popular area for factories and manufacturing in this region).

After you are able to find connectors making a new blade style fuse box will be much easier for all model years of the S30's ... another project in my mind, but to come later ... back to the focus ... engine bay harness ...

At the moment I am going to bid on a wiring harness for a 1978 280z (so if you see it on Ebay, please don't bid against me :laugh: ) and get that shipped here as my guinea-pig. If I loose the auction I will need a source for a 280z harness as I don't want to take mine out of my car when it comes. If someone would be so kind as to lend me a engine wiring harness (and any other electrical harness from a 75 280z) I would gladly repay them with a free harness when all is said and done.

Right now i have the time (this will be a nice part-time work for me) to do this project and be able to see it through. I plan to sell these at a reasonable price and hopefully contribute a great thing to to the Z community to help keep our great cars on the road. It's time this project is completed ....

[280z1975]

oh yea, one more thing ... does anyone know how many different harness's were sold by Nissan Parts? I am curious how many variants they provided to the consumers after the fact ... thanks for the help ...

[Ed]

Give me a yell when your ready for the rubber boot that goes around the harness on the firewall by the battery tray. I have them.

[280z1975]

Ok, a quick update ... I am slowly sorting out all the different plugs that are being used in the engine bay harness's and it's going well. If I can't locate replacement options then I will be getting molds made for the connections.

Now to ask what I have asked before but didn't hear a reply ... How many variations are there out there for the different years for engine bay harness's.

I know my 75 is different from the 78 harness I have been using as my guinea pig. The way it looks right now I am going to have to be making up boards for all 8 years of the car if I plan to make these for people ...

I'll be posting off an on to this thread whenever I have problems or I'm needing some help with the project.

[Zs-ondabrain]

Some company, most likely MSA, told me that there is 11 or 13 variations of the 240Z engine harness. The outer area (inside the engine compartment) is basically the same with the exception of AC activation wires, passing relays on automatics, and a few other things like wipers (2-speed and 2-speed with the single wipe option, the technical term escapes me at the moment)

The correct colored wires are available if you know were to look and most of the engine compartment plugs are available in a few select places. But the kicker is inside the passenger side compartment. Nissan changed alot of connectors on the inside but left the outer part alone.

I don't know all the changes and Variants of the 240Z engine compartment but there can't be too many. Voltage regulator is another one. SOme 280ZX alternator upgrades done on the later 240Z's don't require the diode, and I don't know why.

FWIW,

Dave.

[280z1975]

11 to 13 variations ... fun stuff! :stupid:

Well I plan to at the very least provide a "build kit" for each year with the correct plugs and details on what needs to be bought to complete them. It's going to be a cool winter project for me and one to really help make these cars run better. Thanks for the reply Zs-ondabrain.

[Mike]

The other thread you mentioned started this off a few years ago. I was also in the market for a new harness and was going to work with another member on putting this together. Things sorta fizzled out and I ended up using my old harness and going through a repair. After overpaying for a firewall boot (I think it was $50), I had the thing installed and it worked great.

The trick will be finding new connectors. I believe you can still find the colored wiring. You'll need to create a jig if you want to make more of them. Someone told me you can create a jig using a piece of plywood and laying everything out on pegs.

Anyway, good luck with your venture on this. I would LOVE to see someone get this done with success.

-- Mike

[Arne]

Some company, most likely MSA, told me that there is 11 or 13 variations of the 240Z engine harness.

Been there, did the research, and didn't even get a t-shirt.

I looked into the various variations a lot when I was hunting for replacement harnesses. There are - in fact - 12 different variations of engine room harnesses for North American 240Zs alone. Six for manual transmission cars, two for early Canadian automatics, two for early US automatics and two for all of the later North American automatics.

[JimmyZ]

MT 240's only....

Just a question.. Wouldn't it be possible to make a whole car generic 240Z harness for MT style only? Are the wipers that different?

Really, if you can buy and adapt a generic harness to our Z's then shouldn't we be able to construct something?

I'd love to come up with some CAD drawings if I could get hold of a free harness or two. This way anyone could pick up where the last guy left off.

As for the dash, I'm thinking that most MT 240's are the same?? At least when it comes to ignition, guages, instruments etc. The signal and light switches are another story but that could be a sub-harness.

Arne, I'm sorry you didn't get your T shirt but could you enlighten us some more. Even if the details are fuzzy with time things like this are good to know.

Jim

[Arne]

The problem is that there are innumerable differences. Yes, the '73s have extra wires for the wipers that earlier cars lack. Early cars and late cars have considerably different wiring to the tach and ignition (3-wire vs. 4-wire tachs). The dash harnesses are quite different for long and short pigtail fuseboxes. There are many differences in switches. Size and shape of connectors vary from month to month. The list goes on and on, and the variations change at irregular intervals, not breaking at model years.

As I recall, the engine harnesses went as follows:

All up to 1/70

1/70 - 8/70

9/70 - 12/70

1/71 - 12/71

1/72 - 8/72

8/72 - 8/73

Some of these change points I can understand. Like the 12/70 cut off for Series 1 cars. But why change at 12/71, three or four months into the '72 model year production?

[JimmyZ]

Thanks Arne

A few months ago I was faced with the possibility of loosing my harness. (Something got hot) I didn't like the prospects of not being able to find another.

While we're at it what were the ignition wiring differences? Is there a way to isolate the tach to a different subharness?

What I/we should really be asking is do the FSM's cover things generically like the Haynes manual? Although my Z is a 2/71 I have a '72 FSM which has some good drawings/line art of the wiring harnesses. As far as I could see the 72 FSM had the same type/number of connectors.

Curious,

Jim

[280z1975]

After reading these replies and looking at how things are I don't know if we can come up with a "generic" harness that will fit all of our model years. I'm not saying it can be done, but I am preparing mentally for a tough time at doing it :tapemouth.

For the moment I am focusing on the engine bay harness ... the dash ones are a bit more complicated and they don't see nearly the amount of dirt, moisture and temp exposure the engine harnesses do.

At the very minimum I want to be able to source and make available the required plugs for our harnesses. Yes I know there are 'better' more modern plugs out there, but it will make restoring cars easier and fixing current problems these cars might have with original harnesses.

My work season is about to wrap up and I will finally have some free time to get some quality Z time in ... we can see how thing progress and start to work out some ideas ...

Thanks for the input and ideas ...