Rotate Your Miata Tach
One thing that I’ve seen in some Spec Miatas is that when the motor is at redline, the tachometer needle points straight up. Normally, redline is at about the 3:30 position. Since the rotated tach seems more “race”, I thought I’d give it a shot. Here’s how to do it:
- Remove the clear plexi from the front of the instrument cluster housing. Start at one end and use a flat-blade screwdriver to relase the tabs. Use a second screwdriver to wedge in between the pieces.
- There are two wires that attach to the front of the housing. Once you get the clear part loose, pull the two wires through the back of the housing to get some slack, and rotate the clear part out of the way.
- Use a flat blade screwdriver to lever the tach needle off its post. Be gentle — it seems pretty fragile.
- Remove the two small philips head screws that hold the tach face to the rest of the assembly. The face should come off, likely with some clear plastic parts behind it. The face is held to the clear plastic parts with some weak glue, so they just pull apart. Put the clear parts back where they were in the assembly.
- Trim the protrusions from the tach face with scissors so that it’s completely round.
- Use a piece of paper to trace the center hole in the tach face as well as the two screwholes. This will be your template for drilling new screwholes.
- Punch/cut out the three holes you drew in the paper template.
- Flip the tach face over and use your template to make marks for the new screwholes. Make them perpendicular to the original holes.
- Drill the two new holes with a 3/32″ drill bit. I put a piece of tape over the front of the tach face and drilled from the back to minimize any tearout in the material.
- Reattach the tach face to the tach with the two little black philips-head screws. It will align so that 6750 RPM is roughly at the 12 o’clock position.
- Line up the tach needle with the small black screw on the right of the tach face (or the last zero in the “x1000 RPM” printing). Put it very lightly on the post, then rotate it clockwise just past the pin that sticks out at 0 RPM, and press it on the rest of the way. It should come to rest against the pin.
- Hook up the instrument cluster to the car and check the accuracy of the tach. I had to adjust the needle position several times before I was happy with where it pointed.
- Put it all back together and enjoy!
As a side note, the clear plastic on my gauge cluster was in really bad shape to start with. There were some small scratches, and many white dots, which I’m guessing is dried on Armor-All. I tried all the cleaning products I could think of (Windex, Invisible Glass, water, soapy water), but nothing seemed to help. I had heard about Meguiar’s PlastX on an internet forum, and thought I’d give it a try.
Well, it did an amazing job. It’s a polish, so it has to be worked in to the surface. I used a microfiber cloth, and went over it three different times. Each time, it looked better than the last. I highly recommend this product!
Before:
After: