Tachometer installation on 1968 I6 engine.

[TheDude]

I finally got a tachometer today. I purchased it from Summit Racing, This is the tachometer I bought. I was a little disappointed when I got it though. I assumed the bezel was actual metal and that the picture represented the actual product. The tach I received today is slightly different although the product number is the same: The needle is red and the "Summit" and "RPM X1000" is above the needle making the face appear cluttered. With some quick Paint Shop Pro-ing I can accurately depict the tachometer I received:

I work for a company that is primarily mail order and I know that products that come in overseas (this was made in Taiwan) can sometimes change without notice. The tachometer shown on the website looks less cluttered than what I was sent. I'm not going to make a fuss about it though. I really do not have a big enough problem with it to send it back. I am going to contact Summit and notify them to change the picture to accurately represent their product so no other buyers get a surprise.

Oops, back to the point of this post. I would like to know if anyone else has hooked up tachometers on their I6's (I am sure there are many of you). This particular tachometer has four wires:

Black: Ground. Connect to neg. battery terminal or good chassis ground. Battery terminal is out of the question so what is a good chassis ground?

Red: Tachometer power wire. Connect to +12v circuit at fuse box, or splice into any vehicle harness wire which is energized ONLY when ignition key is in ON (RUN) position.

White: Tachometer lighting wire. Connect to panel lights circuit at fuse box, or splice into any vehicle harness wire connected to the panel lights circuit.

Green: Tachometer signal wire. Connect to appropriate vehicle tachometer signal source. Which is...?

I would appreciate any help that I can be provided with.

Thank you,

Justin

P.S. Along with the tachometer I also ordered chrome exhaust tips. They look very nice and really make the rear of the car look complete. I just need clamps to hold them on now. Pics of the tach, bench seat, and tips are coming soon...hopefully.

 

[TheDude]

I also need to mention that I have a Pertronix electronic ignition installed.

 

[hasa68mustang]

Im gonna go out and check mine... brb.... ok I'm back the red wire on mine went to the wire from the duraspark module and coil, the green went to the green wire from the duraspak module to the green wire on the coil... white was for light, hope that helps..

 

[x21]

For my aftermarket tach, the "source" was the negative side of the coil. Could be the same for yours.

 

[Anonymous]

Unless you have MSD installed, then you have to use the "tach" terminal on the MSD box.

 

[pedal2themetal45]

ONe thing don't forget that you'll have to open the tach and make sure the switch inside is set for 6cly.
they useuly have a switch inside so you can switch for 8cyl, 6cyl, and 4cyl. applaction.. the tach source is usualy the (-) side of the coil unless you have an MSD.
tim

 

[hasa68mustang]

Justin, I got out my newest summit book and saw the tach you ordered, it looks just liek tha picture you photoshopped so they do have the correct image just not on the site I guess, Tommy

 

[Anonymous]

Is a simple Summit tach compatible with the MSD? Or will this need the tach adapter?

 

[Anonymous]

No tach adapter required with MSD, just plug green wire from tach onto "tach" terminal on MSD box.

 

[TheDude]

I do not have an MSD box. I have a stock 1968 distributor with Pertronix eletronic ignition and a Flamethrower coil.

 

[Anonymous]

No worries...I must have crossed two threads.
Good luck and let us know how it works out. I have a spare sun-pro tach kicking around if you have any problems.
Steve-O

 

[x21]

Note the green wire attached to negative side of my Pertronix Flamethrower 40,000 volt coil and on the positive side, the red wire off my Pertronix Ignitor pointless ignition module (i.e.- I have the same set up as you )

I do believe your tach hooks up the same as mine.

 

[hasa68mustang]

x21 your cheating, that makes it too easy..... now Justin I hope I didnt just jinx you....

 

[TheDude]

Note the green wire attached to negative side of my Pertronix Flamethrower 40,000 volt coil and on the positive side, the red wire off my Pertronix Ignitor pointless ignition module (i.e.- I have the same set up as you )

I do believe your tach hooks up the same as mine.

Great. I can hook up the Black (chassis ground) wire now too. What about the white (lights) wire?

x21 your cheating, that makes it too easy..... now Justin I hope I didnt just jinx you....

We will see...



Thanks

 

[Anonymous]

What about the white (lights) wire?

i hooked mine up to my dash lights, i just spliced into the wire from the fuse box, if i remember right the stock box has everything written on it.

i know which ones mine are because i had to make my own fuse box, if it's not written on the box get a test light and start testing the fuses, first with the key off cause there are some hot wires down there, what ever one doesn't light up remember, then turn the key on and test it, if it lights up thats the wire you want

 

[hasa68mustang]

if it's not written on the box get a test light and start testing the fuses, first with the key off cause there are some hot wires down there, what ever one doesn't light up remember, then turn the key on and test it, if it lights up thats the wire you want

When I did mine I was in a hurry and had to goto work so I just hooked mine up to a wire that was hot when the ignition was one, so the light is on all the time except when I turn te car off, and I have yet to change it, the heat/humidity makes it so I really dont like doing things....

 

[Anonymous]

oh i'm thinking about installing a cd player, you don't need a key, it's whenever the light lights up when you turn the lights on

 

[Anonymous]

Thw white wire needs to go to "INST" on the fuse panel.

You want power on when you pull the headlight knob, and power off when you push the headlight knob in.