I want to ditch the 80 mph speedometer that came with my 1980 RX7, and replace it with a 140mph speedo, like my '79 had (as well as some of the later models.)

Has anyone done this before? And if so, what is the best course of action...replace the instrument panel or just the Speedo?

Plus, how hard is it to do, where can I find the parts, and what is the procedure for replacing them?

Thanks.

 

If you get a cluster from a '79, you can drop it in place of the '80. No other changes needed. It is plug-n-play. You could swap just the speedo, but swapping the entire cluster is much easier.

 

What addict said. If you want keep the gauges all matching then drop a 79 cluster in. If you want to keep the other gauges 80 but just want the 79 speedo then you can do that as well. Taking the cluster apart is pretty easy. While its apart test all the lights and make sure they're good and then when you put it back together make sure the little screws and nuts are tight (don't over tighten, you'll break something). When I did this half the screws were loose and making poor contact with the ground plane. Don't forget to reset the odometer to your mileage and keep the old speedo to put back in of you sell it otherwise your supposed to have a sticker that says you had a licensed speedo shop set your mileage verified with proper documentation etc etc.

 

Easy to remove - pics attached-
need L-o-o-o-ong philips to get at 2 rear, bottom screws up under dash. You'll need to lay on your back to see and reach them up amongst all the wiring and ventilation stuff - one on each side of the st. wheel.
photo of rear of speed details them-

Otherwise the only scary moment will be pulling the surround insert that fits around the front of the cluster. Two screws up under lip of dash/cluster right in front of you are easy enough, but then its a fearful pull on the whole surround till the bottom 2 clips release. Feels like your going to break it - other photo details where the clips insert (surround already removed in this close up shot).

Speedo cable has a squeeze clip at the back of the dash, so squeeze-and-pull to remove speedo cable. One big wire cluster also, sometimes easier to disconnect (and REconnect!) with cluster partially pulled out, by reaching into cavity and wiggling loose.

NOTE: st column surround will need to come off first (tip: headlight switch lever's tip just PULLS off).

'luck-
Stu Aull
80GS
(with 79 european metric cluster)
Alaska

 

Thanks.

This will be a great help.

If I can't get a '79 cluster, will a later model work also? Such as an '83?

 

Not as a direct swap. They changed the gauge cluster shape in '81.

 

lots of rewiring, tho I know folks have done it for the extra gauges you get with the FBs -
Archives should detail this??
but can't beat the straight swap to a 79 cluster-
see these on ebay all the time for $25-50...
Stu Aull
80GS
Alaska