Do I install aftermarket oil/temp/volt gauges or not?

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Sep 12, 2015
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SW Ontario
My Car
1971 Mustang Mach 1, M code, 4 speed.
Guys, I need help making a decision. If people remember and it was sometime ago, I posted a thread on upgrading a center dash panel and adding a set of Bosch aftermarket oil, temp. and volt gauges. Trouble is my car is pretty original and actually a 1 of 6. It did not have anything option wise other than a 351 C 4V M code, 4 speed with Hurst shifter and AM radio, that's it. The car has been upgraded somewhat, power steering, brakes and some better suspension parts as well as a stripe kit and hood blackout. That's the way it should have been imo. Nothing that can't be put back as it was if someone so desired.

My dilemma is this; The aftermarket gauges are mechanical, so I would need to drill a F.B.Hole through the firewall to get the fittings through. Next problem is where do I drill it. The heater box takes up much of the under dash so that's no good. I was looking at the very top of the tunnel as a possible site. My intent was to use the double hole grommet that is used in the left shock tower where the fuel and brake lines go through. I bought one, now I can't find the damn thing!!

Bottom line is I must cut a hole for this. There is no other convenient place I can see. What do you guy's think. Drill the hole and do it or put it back as it was with no gauges. I have spent around 250 buck on it, so what to do? And yes, the No Chrome look was intentional.

Geoff.

Edit: Admin edit per Stanglover:

https://www.7173mustangs.com/thread-any-tips-on-refinishing-the-chrome-on-dash-parts

 
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Look for dimples that ford used as locators on the firewall. Holes were drilled using the locaters on assembly line for added options

 
Ok, you talked me into it............ or at least looking more closely at the possibility.

Being that these gauges are mechanical and I'm very limited by the length of the Temp sensor tube, which is very delicate and filled with Ether I believe. I am thinking ahead to a time if and when I need to pull the center section out again, for whatever reason. Do I have enough space for a coil of tubing up and behind to allow for this. This is a question I'm sure many have thought about. An electrical set of gauges is easy, no problem there, but most replacements are mechanical which we all know are more accurate. How have others solved this problem?

All your help and guidance is appreciated.

Geoff.

 
Ok, I'm doing it!! I found about the only suitable location to drill that 1" hole. I'll post pictures later. For now I'm still sorting out the wiring which is taking way longer than I thought. Why can't people just leave the wiring and plug sockets alone. Why do they have to "cut them off" and leave a rat's nest??

More later folks!

Geoff.

 
For now I'm still sorting out the wiring which is taking way longer than I thought. Why can't people just leave the wiring and plug sockets alone. Why do they have to "cut them off" and leave a rat's nest??

More later folks!

Geoff.
Those are my employee elves.  They are out there drumming up business for me. :whistling:

 
For now I'm still sorting out the wiring which is taking way longer than I thought. Why can't people just leave the wiring and plug sockets alone. Why do they have to "cut them off" and leave a rat's nest??

More later folks!

Geoff.
Those are my employee elves.  They are out there drumming up business for me. :whistling:
 That's too funny!

Without doubt, if I was doing a complete rebuild of the car, I'd definitely opt for a new harness, but for now, it is what it is. Hopefully, I have it done today.......... or not! :huh:

 
Well, I'm still working on it. My anal nature took over and I decided to blend in a slight gap between the gauges and the panel openings. Should have just left it as it looked alright. More time wasted!

Anyway, I do have question with regards to the oil gauge. I have opted wisely I think , to go with copper tubing. The question is: do I need to purge the line and gauge with oil before installing? I mean there will be some air trapped in the gauge, will this be an issue and cause an inaccurate reading? 

So here are a couple more pics so far showing where I drilled the 1" hole which is about the only available spot. My plan is to "disguise" the tubing by wrapping the temp sensor with harness wrap and the oil tube with rubber tubing. There will of course be loops to take up the vibration, but these tube will be less conspicuous.

I'm definitely hoping to get it in today......... if my anal nature is satisfied!!

 
This project is starting to come together, but with some major frustration.

I do have one question for the electrical experts and that is, where can I connect the power for the volt meter when there is not an accessory connection in the fuse block? I have a sketch from RCCI that shows where to connect a converted amp to volt gauge which shows connecting to the accessory terminal. I'm thinking the V gauge needs to see voltage put out by the alternator, not after the regulator, correct? I don't want to have to string a wire all the way to the regulator.

Any help would be appreciated.

Thanks,

Geoff.

 
It has to go after the regulator, because that is what the rest of your electrical system is seeing. It can pretty much go in any line, because everything in the car should be seeing the same voltage, not counting for skinny wires causing voltage drops. I have mine on a switched circuit, so as not to be drawing electricity through it when sitting draining the battery.

Funny story, I was having trouble with my stereo amp turning off randomly (or at least i thought so)..... figured the amp was bad so bought a new one ( I was tired of that one anyways :whistling: ) after replacing the amp, it still happened. Eventually I noticed that it always worked fine at night. Then one morning, going to work it was still dark, everything was fine until it got light enough to turn off the headlights. Almost instantly, the amp died. headlights on, amp on....What the heck :chin: :huh: 

So I call the Kicker tech and he tells me that it (actually all amps should) has an automatic shut off if the voltage gets much over 14 volts, which is what the charging system SHOULD be putting out max.  Traced it to a bad voltage regulator...

Sorry for the hi-jack. :threadjacked:

 
It has to go after the regulator, because that is what the rest of your electrical system is seeing. It can pretty much go in any line, because everything in the car should be seeing the same voltage, not counting for skinny wires causing voltage drops. I have mine on a switched circuit, so as not to be drawing electricity through it when sitting draining the battery.

Sorry for the hi-jack. :threadjacked:
 Hi-jack, no worries! EDIT: I took out the "story"

Actually you probably confirmed what I thought I could do and that is tap into any main switched wire. Thinking more logically, I suppose everything inside the car is after the reg, so even if there was the accessory terminal, it'll be the same thing, just a more convenient connection..

Thanks for the info and the funny story!!

Geoff.

 
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What you really want is a RUN-only wire, or an ACC wire that is only on when the key is in ACC or RUN. DO NOT use a battery powered line (e.g. cigarette lighter) or tap into main battery power, as then the voltmeter will always be on and will drain the battery in a couple of days. On 7123's, you want to tap the outside fuse clip below the heater blower fuse and just above the small fuse for the dash lamps. This line is typically colored red/orange and is RUN-Only and is also fused. This line runs to a variety of places, but it is always goes to the main dash cluster connector to power up one side of the brake proportioning valve lamp.

Your voltage reading will be probably 1 to 1.5 V below battery voltage, but whatever you see when running the car at RPM's, consider that your set-point. Above or below that indicates a problem.

 
What you really want is a RUN-only wire, or an ACC wire that is only on when the key is in ACC or RUN.  DO NOT use a battery powered line (e.g. cigarette lighter) or tap into main battery power, as then the voltmeter will always be on and will drain the battery in a couple of days.  On 7123's, you want to tap the outside fuse clip below the heater blower fuse and just above the small fuse for the dash lamps.  This line is typically colored red/orange and is RUN-Only and is also fused.  This line runs to a variety of places, but it is always goes to the main dash cluster connector to power up one side of the brake proportioning valve lamp.  

Your voltage reading will be probably 1 to 1.5 V below battery voltage, but whatever you see when running the car at RPM's, consider that your set-point.  Above or below that indicates a problem.
 Midlife, thank you for your expert advice. I have said many times, when it comes to electrical stuff, I have "limitations".

I do realize I need to find a keyed 12V connection, but what wire is most suitable was the real question. With your help, I now know what to look for. The instructions with the gauges are generic and basically say to find a switched 12V wire and splice in. The ground obviously needs to be clean, bare and good.

If it were not for the fact that I would need to 'run wires all over the place' so to speak, I might have used the factory gauges I have, but with the Amp changed to Volts.

If the factory gauges were more precise, not just hot or cold, high or low (oil pressure), I might not have gone with mechanical gauges.

 I am close to getting done, but it's been a major case of "fix up what some other person has butchered" sort of thing and taken way longer than expected.

Thanks to all. I hope this will help others too.

Geoff.

 
@midlife.

 I have it all in and seems to be working okay. At some point a PO cut a keyed 12V white /red (or orange, hard to tell) and spliced in a radio power lead, with a twist on connector!! As this was part of the wiring clean up, I used that wire to connect the tach conversion as well as to the radio with soldered connections. Tach work fine. The wire has 12 V key on, but jumps to 14 V engine running on the new gauge. I have no idea what that wire was originally for on my 71 no option car and I can't find it on a diagram. I also have a relatively new regulator installed.

Do I need to worry about this voltage. I was not expecting to see 14 V. Should I find a different wire are they all going to be the same?

I appreciate your help on this,

Thanks,

Geoff.

PS I didn't take pics of the tubing installed, but I will post pics of the complete dash. It's going to look pretty good.

 
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