While on a road trip in my 63 last fall, my speedometer,odometer, and trip odometer all failed. They speedo bounced wildly, and the odometers stopped working/turning. I contacted the vendor who'd overhauled the entire cluster a few years back and explained the failures to him. He responded that even though the rebuild failed after only 9,000 miles, unfortunately that's not a rare occurence. He said there are many moving parts in that assembly that can fail, and many of the parts are not available off the shelf. He was using a machinist in a small shop to make some of the small bushings, etc but that gentleman was no longer available. I believe he mentioned that guy had retired and he hadn't been able to find a new source for the small parts. He said to send him only the speedo portion of the cluster and he'll determine what failed and if it can be repaired. I am reluctant to pull the cluster again, remove only the speedo assembly, and send it to him for a repair he may, or may not be able to accomplish. I'm also reluctant from the standpoint that if it shortly fails again, all of the time, $$'s, and effort into the repair was wasted. My experiences have tempered my optimism for a long term fix. I don't question his talent or honesty as he's a long time vendor on the forum with many satisfied clients.
I am looking at options to by-pass the assembly and perhaps using GPS to replace it. In the past I've written down my odometer reading at each fuel stop so I could keep track of how much gas there is in my tank. Using a conservative 10 mpg with a 20 gal tank, I knew when to be looking for a gas station, and not depending on the gas gauge accuracy. I suppose the GPS would supply me with the mileage between stops when I learn how to use it. I also understand that there is a lag between your actual speed and what it is showing on the screen. That is not a major issue as I often monitor my speed using my tachometer reading.
I am not fond of having to mount another small screen on the dash or cluster and a power cord, but I believe I can do a clean install and live with it. My question, since I'm not familiar with this GPS application, does anyone have some knowledge to share regarding this type of lash up? Thanks- lib
PS: I currently have a Garmin nuvi 2505 series available to use.

 

I have a Garmin Nuvi 40 something-or-other in my truck and I rely heavily on it to get me to unfamiliar addresses. It does this with nearly flawless perfection.

However...

I've noticed that the speed indication on the GPS can vary by several MPH while my truck's speedo indicates a constant speed.

So if you rely solely on the GPS for a speed reading, my sense is that you might not get reliable readings.

 

I have used a speedometer app I put on my iPhone to verify my speedometer. I have it on an old iPhone 4 with no service and it still works. Just use a suction mount and plug it into the cigarette lighter, no permanent mods.

 

Replacement gauges are available. Corvette Central has them all

 

I have been working on such a solution in my spare time for a few weeks. My application is for a C1 but there should be no reason the technology could not be used on a C2. I have checked the speed and distance readings from the GPS unit and it seems to be spot on and I have a small servo driving the speedometer needle. The distance updates about once per second and in testing the distance agrees with my truck odometer. The speed indicator also agrees with my truck speedometer. I have an LCD display that shows the odometer mileage, a re-settable trip odometer, and a digital speed readout. However there is a small glitch in the software that I need to work out.
Here is some more information: www.carols62.com/speedo.
Charles

 

I don't use it much, but I bought a cell phone mount off of Amazon and put a magnet on it to stick to the speaker grille. Then downloaded a speedometer app. I can use it as a speedometer, trip meter, hands free phone, and GPS, as all is built into the phone. Bluetooth to the aftermarket radio can play music, etc.
It releases quickly and can charge from the cigar lighter. Cheap - about $15 or so.
Just an option.


Glued plastic under the magnet to prevent scratching the paint

Can also be used to video trips and traffic, front and rear with the top down.

 

I’m interested in that mount and would like to know the brand and model, please.

 

If you mean me, The price has dropped a bunch. Of course, you have to go to Harbor Freight and buy a 2" dia. =/- magnet, remove the suction cup and bolt the magnet on. I don't remember the hardware (bolt and nut) size. I used nylon sheet on the magnet, but felt or something might be better.
New cars don't have any metal in the dash, so they are SOL.

 

The speedometer in my 63 was so far off due to gear change in diff and not a matching speedo gear in the transmission. I used a Garmin GPS for speedometer for two years and never had any issues with PD on the highways. Too lazy to crawl back under car to change speedo gear in trans.

 

I'd fix my speedo, possibly be replacing the gauge. I have not owned a C2 for even a year yet, but I did own the same general vintage GM product for 31 years and never, ever had a speedo/odo problem even once in the 375,000 miles I put on that car, and it had over 100K when I bought it in '89 when I was 17 and I bet you can figure that I sometimes did not baby it as a teenage owner.

 

You should check Hemmings Motor News. Many vendors advertise there who are skilled at instrument repair. A repair that lasts 10 years is, to me, substandard.

 

Not sure what shop you're using but Corvette Specialties of MD West does good work--yes pulling the cluster, shipping it out and waiting is a minor inconvenience. I used a Garmin to figure out what my actual speed is vs. what the speedometer displays at 40, 50, 55, 65, 75 and 85 mph (yes in Texas we have posted speed limits that high) and do the mental arithmetic when driving. Been doing it so long it comes as second nature at any speed I need to travel. I could get it closer with a different cog down in the powerglide transmission I have, but it would still be off some. So I never bothered.

It would personally drive me nuts to have a speedo that bounced around or didn't work. My tach will bounce under hard acceleration (not sure why since I had the entire cluster and all gauges redone about 7 years ago now and it's always been the way before and after the cluster rebuild). The tach bounce on a powerglide doesn't bother me (two speeds and all--it's not going to redline in 1st or 2nd).