Cobra Tach I.D

[shelby001]

Bought it it has been shipped 
   Thanks for every ones help

[shelby001]

 Bought it has been shipped

[shelby001]

Bought & just received it  its Faira June 1966  looks like someone took the face ring off to tangs are missing that hold the face on. Need to test it . any ideas of giving it a quick bench test?

[6s1640]

The circuitry is in line or series with the ignition.  Install from beneath the dash and fire the engine up and  see what happens.  If the original wire ends are in place, there is only one way to hook up.  If the tach is bad, there is a good chance the engine won't start.

On the bezel ring, you will need to find a none OEM Faria tach with a nice bezel to salvage.  The salvage tach should be from the same time period.


Best of luck

Cory

[shelby001]

I thoughtof just running the red to the ign terminal on the coil & black to the (-) ground on the battery & firing up the engine. Blue wire is the light.

[6s1640]

A parallel circuit is not the same as series.  Your're not getting the full resistance of ignition circuit and the amperage could fry the tach.  Remember Ohm's law. Current (amps) equals voltage / resistance.   Give it a try and let us know how well it works.

Good luck.

Cory

[shelby001]

 So your saying it should only be hooked up ro the ignition switch?

[gt350hr]

I thoughtof just running the red to the ign terminal on the coil & black to the (-) ground on the battery & firing up the engine. Blue wire is the light.

  That is NOT the correct way to wire it! It does go in series. The "plug in " point is the connection between the solid red wire out of the switch and the [pink/salmon colored resistor wire that goes to the coil. That is why actual assembly line tachs had molded plugs on the wire ends to prevent wiring them backwards. These tachs are flow meters NOT rev counters.
   Randy

[6s1640]

I thoughtof just running the red to the ign terminal on the coil & black to the (-) ground on the battery & firing up the engine. Blue wire is the light.

  That is NOT the correct way to wire it! It does go in series. The "plug in " point is the connection between the solid red wire out of the switch and the [pink/salmon colored resistor wire that goes to the coil. That is why actual assembly line tachs had molded plugs on the wire ends to prevent wiring them backwards. These tachs are flow meters NOT rev counters.
   Randy

+1

See instructions:

https://sep.yimg.com/ty/cdn/yhst-13525187779972/orgtachs.pdf

and

https://sep.yimg.com/ty/cdn/yhst-13525187779972/6768shelbytach.jpg

Best of luck

Cory

[shelby001]

Thanks for all the info . Just one question is there no GROUND to the tach as both wire connect to positive?

[6s1640]

Thanks for all the info . Just one question is there no GROUND to the tach as both wire connect to positive?

No ground.  I like what Randy said, it is a flow meter.  Does your tach have the original male and female connectors.  If so, piece of cake to hook up.

Cory

[gt350hr]

   "Technically" it's a "case ground" , not a "wire ground" , and only necessary for the light.

[shelby001]

Thats what I was thinking so if these mounted on the dash which was not metal that meant the screws going through the dash pad into the metal acted as the ground?

No there was no plug- ins on the wire ends, matter of fact the wires were cut right at the case ends.

Again Thanks for all  the  input from everyone.

[6s1640]

Hi Shelby001,

Yes on the ground for the light, but not needed for verifying tach function.  With the cut wires, you are going to need to get with Phil Severance in Twin Falls Idaho.  He does an excellent job of rewiring and restore these old tachs.  I have a nice bezel too if needed when you have restored.  See Phil's website:

https://www.phidonrestorations.com/contact.php

Cory

[gt350hr]

 This is sounding more like a "replaced" tach by the over the counter one.  Especially since the wires were cut so short and there is a tab missing. Sending it to Phil is a wise move.
     Randy