Couldn't find anything about actual speedometer repair online, specifically how they can be adjusted. Have an 88 Camaro with a 115 mph speedometer and will put on a 145 mph face. It will then show 80 mph when the car is going 60. Don't want to change the gears in the transmission because finding the right one would be hit or miss and removing the drive gear is a pain. Don't want to use an inline adapter either. The speedometer shops I asked wanted around $125 to clean and rebuild the whole thing. It works fine, just need it calibrated. Still $125. Anybody have an idea how it is done?
Mechanical speedometer adjustment
- Thread starter atikovi
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So not by some adjustment of the magnetic field that rotates the needle? And replacement springs are not generally available?
Originally Posted by eljefino
It wouldn't be hit or miss replacing the gears, just simple math!
80 to 60 is a 25% reduction. So what does that tell me I need? A driven gear with 25% more teeth? If that is even available I'd have to also replace the drive gear which means pulling the driveshaft to remove the transmission tail housing.
It wouldn't be hit or miss replacing the gears, just simple math!
80 to 60 is a 25% reduction. So what does that tell me I need? A driven gear with 25% more teeth? If that is even available I'd have to also replace the drive gear which means pulling the driveshaft to remove the transmission tail housing.
Changing the spring in speedometer will possibly correct the needle but not the odometer. We just get a compensator when changing gear ratios. The dealer counter people don`t like to help with that. Seems to me that one of the hot rod parts suppliers had a solution.
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Don't want to use an inline adapter either.
I would recommend a inline adapter.
Don't want to use an inline adapter either.
I would recommend a inline adapter.
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Originally Posted by atikovi
If that is even available I'd have to also replace the drive gear which means pulling the driveshaft to remove the transmission tail housing.
Not necessary on a Ford, you just get the right color cable gear
Pink, red, black, blue, grey, etc. etc. etc.
It's about a 90 second job to change.
If that is even available I'd have to also replace the drive gear which means pulling the driveshaft to remove the transmission tail housing.
Not necessary on a Ford, you just get the right color cable gear
Pink, red, black, blue, grey, etc. etc. etc.
It's about a 90 second job to change.
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Originally Posted by LDM
Why did you just swap the face? The 115 and 145 speedos are interchangeable and do not require any adjustments on a 82-89 F-body.
Because sellers want $100-$150 for the 145 speedo and a white overlay is $23 which I'd have to buy anyway since the other gauges are white too.
Why did you just swap the face? The 115 and 145 speedos are interchangeable and do not require any adjustments on a 82-89 F-body.
Because sellers want $100-$150 for the 145 speedo and a white overlay is $23 which I'd have to buy anyway since the other gauges are white too.
If you are going to play , you got to pay .
Originally Posted by atikovi
Originally Posted by LDM
Why did you just swap the face? The 115 and 145 speedos are interchangeable and do not require any adjustments on a 82-89 F-body.
Because sellers want $100-$150 for the 145 speedo and a white overlay is $23 which I'd have to buy anyway since the other gauges are white too.
Yes, I own an 89 IROCZ and a 94 Z28, parts for these cars aren't getting any lower. That ebay device you linked to is $88 + $5 shipping. You might as well buy a 145 MPH speedo instead, the cost is almost the same without having to worry if it will work properly or not. Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Also, the only gauges that are yellow are the 90-92 cars for the 3rd gen F-body. A speedometer from those years will not work in the 82-89 years, it is electronic instead of mechanical.
Originally Posted by LDM
Why did you just swap the face? The 115 and 145 speedos are interchangeable and do not require any adjustments on a 82-89 F-body.
Because sellers want $100-$150 for the 145 speedo and a white overlay is $23 which I'd have to buy anyway since the other gauges are white too.
Yes, I own an 89 IROCZ and a 94 Z28, parts for these cars aren't getting any lower. That ebay device you linked to is $88 + $5 shipping. You might as well buy a 145 MPH speedo instead, the cost is almost the same without having to worry if it will work properly or not. Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Also, the only gauges that are yellow are the 90-92 cars for the 3rd gen F-body. A speedometer from those years will not work in the 82-89 years, it is electronic instead of mechanical.
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Originally Posted by LDM
Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Sure about that? The speedometer cable drives the speedometer needle and odometer at the same time. If the speed is showing correctly, so should the miles.
Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Sure about that? The speedometer cable drives the speedometer needle and odometer at the same time. If the speed is showing correctly, so should the miles.
Originally Posted by atikovi
Originally Posted by LDM
Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Sure about that? The speedometer cable drives the speedometer needle and odometer at the same time. If the speed is showing correctly, so should the miles.
You want to leave gearing alone or the odometer will be affected. Speedos work as a balance between the magnetic torque and the hair spring tension so to reduce an indicated 80 to 60 you have to increase the spring force or reduce the magnetic force. Both can often be adjusted.
Originally Posted by LDM
Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Sure about that? The speedometer cable drives the speedometer needle and odometer at the same time. If the speed is showing correctly, so should the miles.
You want to leave gearing alone or the odometer will be affected. Speedos work as a balance between the magnetic torque and the hair spring tension so to reduce an indicated 80 to 60 you have to increase the spring force or reduce the magnetic force. Both can often be adjusted.
Originally Posted by barryh
Speedos work as a balance between the magnetic torque and the hair spring tension so to reduce an indicated 80 to 60 you have to increase the spring force or reduce the magnetic force. Both can often be adjusted.
Picture of spring.
![[Linked Image]](http://www.fototime.com/7502A84BD92650E/large.jpg "[Linked Image]")
Can that be adjusted? With the face and needle installed.
Speedos work as a balance between the magnetic torque and the hair spring tension so to reduce an indicated 80 to 60 you have to increase the spring force or reduce the magnetic force. Both can often be adjusted.
Picture of spring.
Can that be adjusted? With the face and needle installed.
Originally Posted by LDM
That ebay device you linked to is $88 + $5 shipping.
One for $40. https://www.ebay.com/itm/15633056-O...m284cadb2c7:g:kYwAAOSw3wVaU9Pu:rk:1
f:0 Looks like AC Delco had these too. Just can't tell the ratio.
That ebay device you linked to is $88 + $5 shipping.
One for $40. https://www.ebay.com/itm/15633056-O...m284cadb2c7:g:kYwAAOSw3wVaU9Pu:rk:1
f:0 Looks like AC Delco had these too. Just can't tell the ratio.
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Originally Posted by atikovi
Originally Posted by LDM
Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Sure about that? The speedometer cable drives the speedometer needle and odometer at the same time. If the speed is showing correctly, so should the miles.
Yes. All you have done is put a sticker over the current face plate. If you adjust the output of the cable coming into the speedometer/odometer assembly by 20% to match your sticker, it will result in a 20% difference on the odometer as well. Unless you also adjust how the internal operation of the odometer itself, it will be incorrect.
Originally Posted by LDM
Also, the ebay device would make the odometer no longer measure the mileage correctly, as it would slow down the entire assembly, not just the speedometer part.
Sure about that? The speedometer cable drives the speedometer needle and odometer at the same time. If the speed is showing correctly, so should the miles.
Yes. All you have done is put a sticker over the current face plate. If you adjust the output of the cable coming into the speedometer/odometer assembly by 20% to match your sticker, it will result in a 20% difference on the odometer as well. Unless you also adjust how the internal operation of the odometer itself, it will be incorrect.
Originally Posted by atikovi
Originally Posted by LDM
That ebay device you linked to is $88 + $5 shipping.
One for $40. https://www.ebay.com/itm/15633056-O...m284cadb2c7:g:kYwAAOSw3wVaU9Pu:rk:1f:0 Looks like AC Delco had these too. Just can't tell the ratio.
This will not work on an 88 Camaro speedometer. it is for a 88 GM school bus speedometer.
Originally Posted by LDM
That ebay device you linked to is $88 + $5 shipping.
One for $40. https://www.ebay.com/itm/15633056-O...m284cadb2c7:g:kYwAAOSw3wVaU9Pu:rk:1
f:0 Looks like AC Delco had these too. Just can't tell the ratio.This will not work on an 88 Camaro speedometer. it is for a 88 GM school bus speedometer.
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