Ford Muscle Cars Tech Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
691 Posts
Discussion Starter #1
So I have a mystery tachometer that I took off the steering column of a 1970 f350 flatbed. it was not stock to that truck I do not think. I now have it in my 1968 bronco and want to hook it up at some point, but wanted to ask around as there seems to be an extra wire compared to other after market tachometers I have seen.

anyone know what this is/where it came from and how to hook it up?

PSIG also asked me to post up a couple pics a couple weeks ago, so here they are :D

Pic1 (face): 1968 bronco :: tach1.jpg picture by red-tail1 - Photobucket

Pic2 (wiring): 1968 bronco :: tach1.jpg picture by red-tail1 - Photobucket
 

·
Premium Member
Joined
·
2,174 Posts
I believe you need a control box to use that tach. How was it wired in the truck you took it from? Usually it's
Black-ground
Red-power
Green-signal at coil
Yellow-light
That leaves the blue wire which I think goes to the control box. I may be wrong though.
 

·
Registered
Joined
·
691 Posts
Discussion Starter #6
I believe you need a control box to use that tach. How was it wired in the truck you took it from? Usually it's
Black-ground
Red-power
Green-signal at coil
Yellow-light
That leaves the blue wire which I think goes to the control box. I may be wrong though.
It was disconnected from the rig I got it from, I do know the green wire was all the way into where the coil was, so I assume that was the signal wire, but again, it was disconnected. I did not see any boxes in the truck I removed it from.
 

·
Registered
Joined
·
10,315 Posts
Pop it out of the cup and see where the wires go. The colors listed are the same as I gave you with RED/BLK/GRN for tach function and either blue or yellow for back-light and/or internal shift light (a Sunpro I have is blue for back-light), but a visual should give you and idea of wire function. The internal PC boards of often marked cryptically for factory assembly and may give some clues or confirmations.

Keep in-mind after the three basic wires, the others can be almost anything. Some tachs use the extra wires for multi-coil setups, or to set operation for 2/4/6/8 cylinder when a certain wire is powered or grounded, etc.

David
 

·
Registered
Joined
·
691 Posts
Discussion Starter #10
Finally got around to opening it up, and found out it is pretty burned up inside. Windings and all that look good but I was wondering if I can swap the guts out of this tach with one from another newer tach? It only has a single wire going to the windings for the needle. any ideas for doners?
 

·
Registered
Joined
·
10,315 Posts
That can be done, but you must match both the needle sweep angle and the RPM range to do it without modifying the electrical circuit. This assumes it's also an 8 cylinder tach. While you could find more potential donors from high-revving 4-cylinder cars, unless they have a hack you can use for twice the pulses, again - it won't work right. Not trying to throw a wet towel, and anything can be done with enough work or money; but unless it has some great sentimental value or it's a priceless collector's item - I'd look for a fresh one for cheap online or at swap meets. I saw maybe 5 or 6 similar to that for under $50 at the local meet last weekend. Big shows have lots of them for the choosing.
:tup:
David
 

·
Registered
Joined
·
691 Posts
Discussion Starter #12
valid points, as per usual :)

however I would like to fix the unit if I could, If I post up some photos of the damage, can you help me ID things that need replacing?
 

·
Registered
Joined
·
10,315 Posts
We can certainly try. The original current tach's in '60s and early '70s Fords often only need the solder joints re-flowed to work fine. An occasional capacitor may be dried-up too. Let's see what yours is doing.

David
 

·
Registered
Joined
·
576 Posts
or at swap meets. I saw maybe 5 or 6 similar to that for under $50 at the local meet last weekend. Big shows have lots of them for the choosing.
:tup:
David
I'v always had ot use stuff till it was worn out or broken.....$50 bucks for a ...maybe good....part don't seem like good sense to me....I just figure they are on the table cause they are broke....
 

·
Registered
Joined
·
10,315 Posts
I'v always had ot use stuff till it was worn out or broken.....$50 bucks for a ...maybe good....part don't seem like good sense to me....I just figure they are on the table cause they are broke....
I leave collateral (my big friend) and go test it on the nearest car and touch red, black and green to BAT (+) and (-), and coil (-) proved function in two minutes. Of the tachs I've purchased at swap meets, only one was toast, and maybe two were out of calibration. Can't say about online used stuff, though I would think that would be higher risk, as they know you can't punch them and yell names about their mother in front of their girlfriend. ;) I'm also talking about good tachs (factory, Autometer, Dixco, Fischer, etc.) - not cheap import crap that was under $50 to begin with.

David
 

·
Registered
Joined
·
1,786 Posts
finally got my butt in gear to get a photo posted.

EWWW looks pretty toasty. But still MIGHT be ok if you go over the joints and replace the toasty bits... (but wouldnt hold my breath either)

If the sweep is the same as a Sun II or something just swap the faces and have the old look with new internals...
 

·
Registered
Joined
·
691 Posts
Discussion Starter #19
I have a brand new in the box Arrow tach for the early 70s that looks real close to that you can have for $75 + shipping .





Thank you for the offer! I am interested, but I can't afford it right now, LOL. do you have to sell it right away?
 
1 - 20 of 21 Posts
Top