Joined: 22 Jun 2005
Location: TX, USA
1969 Mercury Cougar XR7
|Posted: Wed Dec 07, 2016 9:24 am Post subject: How To: RCCI Mini-tach install for 67/68 (mo2872)
So you have a plain vanilla, standard Cougar, and want a tachometer without revamping your entire instrument cluster. What to do, what to do? You visit www.rccinnovations.com, and pick up one of their G1S mini-tachs, that's what! This is a great product to replace your "clock delete" in non-XR7 cars, and was a snap to install(once I finally did it).
First step: disconnect your battery for electrical work!
You will have to remove your cluster from the dash in order to perform the swap. I had originally put on a molex connector, but kept pulling wires loose from the pins when disconnecting, so I nipped that off. Once out of the vehicle, this is what you will be looking at:
Remove the screws along the perimeter to part the halves of the cluster, allowing you access to your clock delete. I've already installed the tach in the following picture, but you will get the idea what you should see when opened:
While in there, it is adviseable to "relief cut" the metal lens-holder, allowing more light to hit the tach during night operation. To do this, remove the lens holder:
In the picture above, you can see where I had done a small relief cut long ago, but discovered it still did not allow enough illumination. So, while I had it out again, I decided to remove the same amount of material, around the entire perimeter of the hold-down, and ended up with this:
Once trimmed, I shot it with semi-flat black from a rattle can, and re-installed. At this point, I re-assembled the cluster housing, with the tach now in its new home.
And now the fun part, WIRING....which Bob has made super-simple. The tach has three wires, switched 12v(red), ground(black), and -coil(green):
I ran the wires along the instrument harness, zip-tying in a couple spots. I then terminated the ends of the three wires with spade connectors, crimped, and covered with heat-shrink:
The hardest part of this whole process, for me, was where to pick the 12v switched power from, but thanks again to Bob, he advised I could pick it from one of the fuses. So, I made up a red wire, with one end containing the female half of the spade(to attach to the tach wiring, which got the male half), and the other end having another male spade. This red male spade was inserted into a fuse slot, along with the fuse. I neglected to take a picture of that, but it worked like a champ. You will also need to make up a ground wire, and the - coil wire at this time. I ended up with this:
Connect these three wires to your tach, making sure to match the colors! Then all that is left is running them. I put my ground wire to a common ground behind the dash, since it was convenient. I ran the red power to the fuse panel, as described above, then ran the green through an existing hole in the firewall, to the negative side of the coil:
At this point, all I had left was tidying up, so, zip tied to the factory harness in a couple spots, and called it good:
To be continued........
[hr]Now, will it work? I'm no electrical guru, so, I will admit, I was not confident. I re-connected my battery, jumped in, and gave it a go......
You can make out the orange pointer just under the 2k RPM mark. The picture doesn't really do it justice, as I could see the needle just fine, especially since relieving more material from the lens holder. I went through a few rev-cycles up and down, just to see it working. It was, after all, fairly late in the evening last night, and I didn't want to annoy too many of my neighbors!
All in all, this was a simple modification, and, with Bobs attention to making things look like "it came that way", I am more than pleased with my new tach!
I took the opportunity to take a spin Sunday afternoon, and, am pleased to say, the tach works brilliantly, and is very easy to see in the clock position, even with my slightly smaller diameter steering wheel......