How to calibrate 280zx analog speedometer?

[VinhZXT]

Hi all,

I got the a couple of 79 280ZX speedometers and they both display the wrong speeds. Both are displaying different speeds also so I think they are both off. Anyone know how to recalibrate this type of speedometer? Thanks for any help

[datsunlover]

If you know what rear gear ratio you're running, what size tires you have, and what transmision you are using, you should be able to figure out which color plastic gear to use on the sender unit (located on the passenger side of the transmision) to get the spedo in check. I don't have the link, but I've seen it posed a few times.. actually, there are a few pages on the web that have all the numbers and charts you'd need to figure it out. Maybe someone else will chime in who has a link..

[COZY Z COLE]

Check this thread.....

 

http://forums.hybridz.org/showthread.php?t=100558

 

LARRY

[VinhZXT]

Guys,

That was my post that I asked a few weeks back. Yes I have read that page many times before. I have a 3.7LSD and a blue cog in my BW T5. Both of my analog speedometer displayed different speeds vs. my RPM and they are both not correct. I need someone to recalibrate the magnet and the needle inside the speedometer. I opened up the speedo to check and there is nothing to it. Just a dumb magnet attached to a rotating metal wheel that used to turn a needle. The needle is restraint by a little tiny circular type spring. I bet you this little circular spring is dead or weak and therefore display incorrect speed. I guess I can recalibrate it myself if I have some type of device to turn it at a certain RPM and then I can find ways to strenthen this springs. Anyway I will look into it closer.

[VinhZXT]

OK I figured it out. That circular spring has a pivot point and that point is attached to a small plate. This plate is made so that you can slide it around to increase or decrease the tension on the spring. I have the dremel tool to help me get the exact RPM to set the speed but the dremel is spinning the wrong way so it does no good for me. What I ended up doing was drive my car and see how much is it off (let say 10MPH). Then remove the speedo and hook up to a cordless drill thru a speedo cable and get it to max speed it can get (Let say 40MPH). Then turn the pivot plate for the spring increase or decrease depends on how your speed was off. Move a little at a time and recheck the speed. Keep doing this until your max speed is the original speed minus or plus the off speed (the 10MPH). Then you are done.

 

PS. If you have something that can spin exactly 1024 RPM then you can set it at 60MPH just like what it says at the bottom of the face in small texts. No more playing with the wrong cogs to get my speed correct. Good luck guys

[Afshin]

Great info, thanks

[VinhZXT]

Here is a picture of the spring and the pivot plate I was talking about.

 

PS. I would try to calibrate it at around 60MPH for the most accuracy around that speed. This spring is sitting right behind the face plate. Becareful when you removing the needle. It's very easy to break it. Good luck all

 

BTW I just open up the Z speedo and it's the same thing. I am still going to try to put the Z speedo into the ZX housing. Here is a picture of the RPM replaced with the Z face

[Guest 305240]

Great read Vinh. This should help lots of folks out. Also, this thread should be made a sticky.

[Josh280z]

how did you go about removing the speedometer needle??

[Tony D]

Needle Puller

[Josh280z]

Right

[magnum44]

I changed the pinion gear that goes on the side of the tranny where youre cable goes in and changed the gear to the white Nissan one which is 19 tooth. and now im only off by about 3-4 mph.. compared to like 15-20 before....this was done on a 83 turbo.. because I went from digital to analoge..