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Gauge, Fuse box, Electrical questions...


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I'm starting a separate thread about this from my FF-1 thread since some of this applies to anyone with a 70's Subaru...

 

Anyway, i'm trying to decide exactly what I want to do with my FF-1 in terms of Gauges and other electrical components. I'm working on mounting locations and such, so I need an idea of what i'm going to do. Price of all this is not a concern, I'm more worried about if it will actually work...

 

Right now, I've got two options:

 

1) Keep the stock combo meter (gauge cluster) and add at least a tachometer, and modify the stock wiring harness to include the MSD ignition and replace the original (crappy and worn out) fuse box.

 

2) Replace the stock combo meter with all new gauges; Speedometer, Tachometer, Voltmeter, Water temperature, Oil Pressure, Fuel meter... And replace the original wiring harness with all new wiring along with a new fuse box setup as well.

 

Now, If I were to actually go and replace all the gauges, I have some questions about the specific gauges and how to set them up with an early EA Subaru...

 

Speedometer: For a mechanical gauge, do I need to run a different speedo cable, or do I have to find a different one or modify the original one?

 

Tachometer: No questions here actually, i've done one before, no big deal, and my MSD ignition has a tachometer spot to plug into.

 

Voltmeter: Short sweep or Full sweep?

 

Water Tempurature: This gauge gets its information from the sensor on the intake manifold, correct? Does the OEM sensor work OK for aftermarket gauges?

What tempurature range should I look for? 100-250, 140-280, etc.

 

Oil Pressure: Now this is one of the ones i'm concerned about...

Should I do mechanical or electrical? I'd rather not have to run an extra oil line to under the dash, but whats involved with either setup and has anyone done it with the early EA motor?

I've talked to some people and read that you do need to replace the sensor on the oil pump in order to use an Oil Pressure gauge (since its just a switch and not a temp sensor). What exactly would I need to do in order to do this? Do I need to modifiy the oil pump in order to run the appropriate sensor?

 

Fuel Level: This is the other complicated one...

There are SEVERAL types of fuel gauges out there from what I see, and I mean just the electrical specifications. Some say 0 ohms empty, 90 ohms full. 240 ohms empty, 33 full. And several other iterations...

How do I find out what the output range is for my fuel level sensor in the fuel tank? Is it listed in the service manuals that I have, or do I need to do something to figure it out? Would I even have to go so far as to replace the fuel level sensor itself???

 

 

Alright, those were my questions about gauges... Now lets move on to fuse boxes and wiring in general.

 

My FF-1 is a simple car in terms of wiring, about as simple as it could be. And i'm actually going to make it a bit more simple by not using a couple accessories originally with the car (interior dome light, door buzzer, radio/speaker) and even simplify the engine wiring by using a alternator with a built-in regulator. I will be adding a MSD ignition as mentioned earlier.

 

Anyway, the original factory fuse box was mounted in the engine bay. It was quite small, only had ~5 or 6 fuses in it. I'd like to move it under the dash and use an upgrade unit and keep everything more centralized, any suggestions on what I should use for that?

 

I have found some "fuse blocks" on summit racing and other sites, but since i'm a wiring n00b and probably will need help to do this since I know squat about wiring... Which kind of fuse box should I be looking for?

 

 

Anyway... Thanks for any help that anyone can provide in advance. I hope this thread does eventually help other people as well about these subjects :)

Edited by Kostamojen
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I did see the "painless" fuse blocks on summit. But I didn't see custom wiring harnesses either...

 

And I'm not sure how i'd do that, I don't even know what lengths to put down for anything.

 

They are basically universal. It comes with a fuse box and harness. All the wires are extra long, you run them to all the lights, wipers, horn, ignition etc and splice them in at the accessory.

 

It's not a bad option if you have never wired a complete car before and your old harness is in bad shape. The street rod guys use them a lot.

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Alright, well, I still need to figure out IF I can even use the gauges before I go ahead and do a whole harness and new gauges...

 

I did more searching, and found a couple threads about the "senders" included with the gauges.

 

Aparently some people use adapters for the Water temp gauge sender, since its a BPT and the Subaru one is a NPT or something like that. What exactly are the two threads and whats needed to adapt it?

 

And regarding the oil temp sender, it just needs a re-thread right? So any machine shop can do it?

 

I'm still not certain about the fuel level gauge or the speedo with the mechanical wire yet... I need more information about those.

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