Hey Guys,

I'm stuck.

Back in the fall, my "Chock and Check Relay" went funky, and started causing alternators to blow. I went through three alt rebuilds before I finally found the problem, but finally figured it out at the end of the season. The car has been running fine, charging fine, etc... but in the process of blowing 3 alts, I had a few casualties.

Among the dead were my fuel pump relay, my signal light relay, a pair of ignitors, and my gauge cluster.

Everything else got patched up, and I managed to buy a gauge cluster from a fellow forum member (thanks Feds!). The problem is this:

The gauge cluster I bought to replace mine has a lower Odo reading. My car has 220,000-ish km on it, and the new cluster has closer to 180,000-ish. So I want to figure out how to roll the new cluster *up* to meet the old one.

It's a tough question to ask because I know that right off the bat someone is going to blast me for asking it because whatever info people give here could be used for dishonest uses. If anyone doubts my reasons, I'll gladly take pictures of the car, it's cluster, and the new one. And I'm not trying to roll it -back- I'm trying to roll it forward. I know there's not a big difference (if you can do one you can do the other) but basically if I *don't* figure out how to do this I will, in essence, end up with a "rolled back" odo because the new gauge cluster has less kilometres on it than the old one!

Help!

Jon

 

My only question is why???? Here in America it does not even matter. Cars as old as ours are exempt when disclosing the odometer reading.

Hell maybe you can wear out a couple of drill motors "drilling it forward"

 

You could take the clusters apart and swap just the speedo/odometer parts to get your mileage back right. Or, you can pull the speedo cable off and hook it to a power drill. Run the drill with the trigger locked till the milage is where you want it.

 

aw *** on, that electric drill in reverse crap aint gonna work. you have been watching Barney and Big Bird too much. just use your fingers to force the numbers to rotate or you can take that rod behind the numbers and roll (look at it and you will see what Im talking about)

 

Jon, let it go. You've gone public with the true mileage, the truth is out and your conscience is clear if you ever try to sell the car. If you really need it to read exactly the same as your old odometer you are getting even more compulsive than me and that's bad.

I'd just start working on putting those 40,000 kms back on from behind the wheel, it's like getting two years of free driving.

 

Well we're not exempt from disclosing the odometer reading, but I don't think it'd be a problem because they only check it when the car changes ownership. So really, the mileage on the "new" odometer is probably still higher than it was five or six years ago when I got my safety check done and I wouldn't have a problem.

I just hate the idea of my odo being wrong. I'm an honest person, and I'm also proud that my little 12a has lasted over 220,000km without a rebuild.

Tomorrow I'll see if I can get the cluster disassembled to the point where I can get to the little number rollers. It doesn't look like you can get to it from the front, there's a clear plastic strip in the way. I was just wondering if anyone had actually done this that could give me pointers... As it is I don't want to take it apart if I don't know I can get it back together! ('cause then I'd have to get -another- gauge cluster and go through it again, lol)

Oh, and does anyone know where the resistor is that you have to change for the rev buzzer on the S3 models? It doesn't look like the S1 cluster that's in the tutorial on changing that.

Jon

 

Lol yeah.... I am a little compulsive when it comes to my 7.

Truth be told, the last two years I've put 3% more on the odo than I have on the car because my tire diameter is 3% different from stock...

It just bugs me

Jon

 

Hold on turbo....follow the "call of the thread".....he wants to move it FORWARD.... Even "big bird" can figure out how to hoo the Makita to an ODO and make it move forward....

Like I said earlier...he might wear out a drill waiting to move it that far FORWARD.

 

Unless the cluster circuit board is toast, simply swap the new gauges to the old board and speedo, simple.

 

Thank you. At least you read before speaking

 

ooops I should have proof read my post...forward

 

If it's that much of a concern, why not just document the miles on the old odometer, the date you changed it, and the miles registered on the new one? Basically, just set a new base line.

 

well if he's like me he may end up losing the documentation half way through, or forget about it or something lol. so yeah, just tie it up to a spinning device of some sort and let it wind man lol

 

actually in ohio, it does matter. the odometer readings are not exempt and are ALWAYS recorded and a title can be printed with an odometer discrepancy.

take the speedo out of the cluster and take it to an authorized shop that works on speedometers and they can turn the mileage to whatever you want and with paperwork for future sale or discrepancies. if you attempt to move the numbers yourself, the odometer will malfunction as designed and will never be the same.

 

What Trochoid said, swap the speedo's between the clusters. There are still speedometer repair companies in business that can do this for you - legally - if you don't want to tackle it yourself.

 

I guess I am afraid that if you go in there dorking with your odometer and it's little wheels and gears, you will end up ****** it up. I don't know how many times I have started out on some little project "to make it right/better" and made it worse than before or ended up breaking something else!!!

Sometimes it really is better to follow the rule....."if it isn't broke...don't fix it!!

 

The guage cluster comes apart fairly easily. If your old speedo and odo are OK, you can transfer parts between without issue; move the old speedo/odo assembly to the new cluster, or the new guages to the old cluster.

You'll have to take it apart that far if you were going to monkey with the innards of the new odo, anyway.

I swapped my original 80 cluster for a 79 (wanted the 130 speedo!) and somewhere in the intervening 20 or so years lost my "conversion factor" paper that had the starting mileage of the replacement cluster. So, my mileage is uncertain - - besides the odo calibration being off because of the swap.

 

Theres two ways to do this, like Divin says you can swap the old odo into the new cluster or you can twiddle the wheels by hand but you have to take the odo out of the cluster to do it easily. Either way you have to remove the cluster.

I know on an SA you can twiddle the number wheels easily with your fingers and a small screw driver no problem. Not sure about the FBs, they may have a tamper system built in that changes their colors or something if you do it. Its easy to figure out once its out because you can see how it all works behind the display.

 

I bought an '83 style cluster for my 81 (130mph vs 85) and I had to roll the mileage back to match what my car had. I think the cluster had 140,000 and my car at the time had 100,000 or so. I really wanted the higher speedo, but not the higher mileage.

Once you pull the cluster apart look at the odo. I dont remember what I did specifically, but its REALLY hard to screw it up. By unbolting/unclipping one side you could pull the number drums off of there little seats that lock them in place and spin them. You have to do it like one drum at a time, and you end up tipping it around to pop all the drums in and out. And its a PITA to keep them all perfectly lined up while you do the last few digits. You end up with nearly all of them loose and trying to hold them in place.

Either way, the DMV will never know, and it doesnt matter anyway, I adjusted it to Exactly what it was on the old cluster. That way the Ohio DMV didnt mark my title that my car has a fraudulent odo reading.... Not that I am ever selling this car lol.

I wish I could be of more assistance, but I didnt think to take pictures or remember the specific procedure because people around here seem a little touchy on the subject. If you have enough mechanical ability to take the cluster apart, you will be able to figure out how to do it I am sure. Just take your time and be patient with it.

I dont condone doing this to a car just to get lower mileage, that said, if your going to tell me I am ahorrible person for doing this, and yet have no problem installing a cluster into your car with lower mileage than what your car has.... Well I dont think I can tell you here what Id like to say to you.

 

^^^

Loki Where the heck you been man, I havent seen a post from you in forever!!

 

Im on here from time to time, moreso recently. My girlfriend got a 7, and I have forgotten half of the things I used to know about stock 7's (Havent had a stock one for years now lol). The boards a great place to refresh your memory.

 

Okay....some mountains are being made out of mole hills here.

I just looked at a 84-85 cluster that I have. It is possible - and easy - to remove the speedometer/odometer assy (called a speedometer head) from the cluster. So the simple solution is to pull the 220KM speedometer head from the defective cluster and put it in the replacement cluster. This task will not require you to remove the needle from the speedometer, diddle with the Odometer or mess with calibrations.

You will need to remove the front portion of the cluster - look for screws that hold it in place. The speedometer head is held in the cluster with two screws....that is it. While you have the cluster appart it is a good idea to replace the light bulbs, clean out the dust, and polish the lense (be careful they scratch easily). Also you should lube the cable while you are at it. I believe they come out of the housing at the transmission. Use a light grease only - NO GRAPHITE. Graphite kills speedometer bearings.

Picking odometer in a Mazda doesn't require it's disassembly. Been there and done that when I managed Kansas City Speedometer. I'm not telling you how...you don't need to know.

Finally, when changing speedometer heads to get a higher indicated top speed - 85 MPH to 130 MPH - there are no calibration requirements. Both an 85MPH and 130MPH speedometer have the same calibration - 1024 Cable RPM = 60MPH. This is usually stamped or printed somewhere on the instrument. BTW, domestic mechanical speedo's are 1000 cable RPM = 60MPH.

 

Wow that post made this whole thread worthwhile, thanks Scott. Makes me want to go out and mess with my odometer.

 

Awesome info indeed.

So I decided to just install the cluster (before I had read that post) and as it turns out there are other issues with the cluster. Dead tach, the speedo is bouncing and the fuel gauge reads nothing at all.

So if anybody has a spare S3 cluster they're willing to part with, I've put up a WTB in the Canadian Classifieds. Offering $50, but accepting anything reasonable.

https://www.rx7club.com/canadian-sale-wanted-classifieds-120/wtb-s3-gauge-cluster-834303/

Jon

 

I know this is true for the FB's (in fact, if you go back far enough in their old catalogs, RB used to sell 130mph speedos for FB's - direct swap) but do you know if this is for-sure true for SA's as well?

Reasons I ask:

1) The part numbers for the speedo driven gear gear change at the 79/80 serial # breakpoint (574179/574180).

2) I have a '79 130 speedo in my '80, and even when I was running stock tire size, it has consistantly read about 7-8% high, both when measured against a GPS, and against calc'ed 3000 and 4000 rpm speed.

I was in-process of trying to track down a '79 driven gear assembly, to try to correct for this, as it's gotten a good bit bit worse since I swapped down in tire size. The speedo doesn't bother me as much as the "tax" it's apparently placing on my odo, charging me for more miles than actually driven.