Speedometer Calibration

Not sure this is posted in the right place!

Is there a way to safely recalibrate the speedometer without breaking it. When I had a drill hooke to it to trigger the speed sensor, I ran it the wrong way. I would have thought that CW would have been the correct way.

Is there a way to twist or remove the needle to get it back to the correct setting without damaging it. It sits at 7 MPH without moving. While driving it appears to be about 12 MPH off. It would be nice to have it reading closer than this. It has the correct speedometer gear (42T) & tire sizes according to the parts manual.

Thoughts

There's a dial on the back that controls a clock spring, you can adjust that to fine tune the calibration.

Turning the drill the wrong way will not screw up the needle positioning as there is no mechanical link ebtween the needle and the cable. It's a simply flying magnet type deal.

TT,

Is 12 MPH considered a fine tune or not? Will I be able to see the change while adjusting so I know I'm going the right way?

Thanks

While collecting data with WinALDL my speedometer shows that it's 13 MPH off. Which way would I adjust to make a correction.

Thanks

That much, with a drive & driven gear

The WinALDL program is showing the right speed off of the speed sensor. If that is correct, what would a gear change do? The speedometer is not correct.

I would take the head to a speedo shop.

The vss is on the back of the speedo and basically works with a light emitter, pickup and a rotating mirror, if winaldl is showing the correct speed, try adjusting the speedo all the way, if that doesn't do it you need too send it out to be checked. That error is in the tension of the clock spring and that's exactly what that adjuster adjusts There's a pointer and a scale on it, that scale may well be mph, not sure. I never fiddled with it, just noticed it was there

Twin_Turbo said:

There's a pointer and a scale on it, that scale may well be mph, not sure. I never fiddled with it, just noticed it was there

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That scale means doo-doo.

Is it not possible to remove the needle. The guy here that is the only Corvette shop in town. Said if you are very carefull you can pull the needle straight back, then put it back on where you thick it might go.

Where would I find a Speedo shop?

You could do that, does the needle come down to 0 when not driving?

The needle is at about 7 -8 MPH.

http://www.classicgaugesolutions.com/

I am lucky. We have a speedo shop here in town. The guy has been there so long, he has some NOS parts from the 20's.:nuts:

big2bird said:

http://www.classicgaugesolutions.com/

I am lucky. We have a speedo shop here in town. The guy has been there so long, he has some NOS parts from the 20's.:nuts:

Click to expand...

Sounds like he's got alot of experience & hard to find parts.