I would like to roll back the odometer on my car so I can start out at zero with my new engine. How hard is this to do and does anybody have experience or suggestions they can provide??

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Future replica police unit: 1968 Plymouth Belvedere 4-Door (aka "Christine," according to my wife).

The word is that you must pull the inst. cluster, remove the face plate, remove the speedo unit, pull the "C" clip and remove the odometer "barrel".
Once out, you remove a 2nd "C" clip that that allows you to slide all the individual number "circles" apart, keep these in order and restack them with all the zeros lined-up. re-install everything in reverse order.
It's a good amount of work, if you decide to do this job, dis-connect the battery before starting. (Cluster removal can short-out wires, especially the ones leading to the amp meter)
DD

Doc, sure that would work, but there is an easier method. If your going to pull the speedo out, you can use a small flathead screwdriver blade, hack off the handle, put the blade part in the speedo where the cable would be, and spin with a drill. If you want to leave the speedo on the car, follow the speedo cable back to the coupler on the inner driver side fender, pull the cable end from there, and spin the cable with a drill as before. I'm not sure if all cars came with two piece speedo cables with a coupler in between. If yours has a one peice system, pull the cable out from the transmission end and do the same. Just be careful to spin the drill slow enough so the needle doesn't peg and bend itself.

I'm not sure how the unit will behave if you spin it in reverse. If push comes to shove you can just go all the way forward and roll it over.

In a late model instrument cluster doing what doc says, except you can just put the cordless drill on the tumbler nub and roll the digits back quickly (took me about 2 minutes) to the number you want. Doing it Pierre's way, you have to put the drill in reverse to actually get it to roll forward, if the drill is in 'forward' mode it'll make the cluster act like you are driving in reverse (the speedo is reacting to the cable through the little plastic worm gear that tripps the OD...)

It's a real pain, but while you're in there check you connections, be careful, and make sure your bulbs are changed...etc...

good luck,

-D.Idiot

I tried the cordless drill route when I installed a LeBaron dash into my '79 Volare. The cluster read approx. 46K and it took several hours to roll back a few thousand. (1mile/min).
I ended up disassembling the cluter and moving the tumblers by hand. Only took a few minutes. The LeBaron dash has a trip odometer. I don't know if that makes a difference or not, but everything has worked fine for over 5K now.

Disassembling the cluster and reconfiguring the numbers only takes a few minutes? Wow... It takes a while for me on the duster, I have to drop the steering colum so that only adds to it.

Hmm, how fast was your drill spinning to get 1 mi/min ? That is only 60mi/hr so you can go at least double that before the speedo pegs... I would rather sit on the drill for hours then go through dropping the cluster again.

So driving in reverse reverses the mileage? Hmm I thought the tranny had something in it to compensate for that I didn't know that would work.

If I remember right, they're like 100 rev's per mile. Using a drill you'll be there a while -- or risk damaging the speedo.

Even though it's a lot of work, I'd disassemble it.

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My truck is a Frankenstein creation
Built from the dead carcasses of others
And brought BACK TO LIFE!

I used a 3/8 variable speed electric drill (not cordless). with the trigger locked for full throttle. I was turning the speedo/odo BACK so the needle was already pegged (at zero). I didn't think that it would healthy for the odometer and my drill to run it for hours on end, so I opted for the dissassembly. Only took an hour (approx). Since I never had done one before I took it apart farther then I had to.

Hmm, 10krpm dremels

Hmm, 10krpm dremels

Yaahhhooooo. 6,000 Miles per hour. Now that's a fast slant!

Why do I have cartoonish pictures flashing around in my head. A little Wile E. Coyote maybe.

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My truck is a Frankenstein creation
Built from the dead carcasses of others
And brought BACK TO LIFE!

I think I'm going to go the disassembly route. The drill sounds nice but it would probably take hours (or days) to roll back 20k miles. You guys have given me courage. Maybe I'll try it this weekend. I'll let you know the results.

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Future replica police unit: 1968 Plymouth Belvedere 4-Door (aka "Christine," according to my wife).

When my dad had his 76 Charger, I helped him change the engine, and I remember he wanted the odo to read the same as the one did from the 77 LaBaron in the JY that gave up the engine. The 3/8" cordless drill on the cable got us a steady 85 MPH. We ran it about 1/2 a day before Dad started to worry about wearing out his drill, and we gave up and said the he!! with it.

I know when I get my original engine back from the rebuilder I will still want the original mileage on the car, so for maintenance purposes I will install an hourmeter under the dash. Oil changes every 250 hours of operation. You can always record on a sticker in the glovebox what mileage the car had when the motor was put in, this way the original mileage won't be lost. That's what I'll be doing. At the very least grab another speedo from the wreckyard just in case one of the many tiny parts get lost, if you want to set the speedo back.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

I took a closer look at the removal yesterday and found out I would have to remove the padding around the instrument cluster. For the moment, I have chickened out, but I may give it a try when I'm feeling VERY VERY patient. For now, I have simply recorded the mileage.

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Future replica police unit: 1968 Plymouth Belvedere 4-Door (aka "Christine," according to my wife).

Yeah, there are a few other things worth remembering here:

(1) Doing what you want to do is common, but is also a Federal crime.

(2) Using the drill (dremel, cordless, whatever) method will put as many miles worth of wear and tear on your speedo and odo as driving that actual number of miles would. Also, those numbers aren't meant to spin at super high speeds, so wear would be increased. So if you want to do this, definitely use the disassembly method.