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Topic: Speedo Circuit Board

in Forum: C3 Electrical


Speedo Circuit Board

Posted: 9/7/06 8:46am Message 1 of 8
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Canada
Joined: 10/2/2005
Posts: 164
Vette(s): 1980 Black on Red with 383 Stoker 4 speed. T-Tops

Good day all, I have a question regarding the circuit board on the Speedo/Tach. I did search the forums and found a couple of topics but no answers. I wish to replace the speedo with a 140MPH and currently have the Canadian version of the 80MPH/140KPH, my question is are the circuit boards the same or are the Canadian boards calibrated to the KPH that we use?

Thanks in advance

T

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Speedo Circuit Board

Posted: 9/7/06 8:59am Message 2 of 8
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Duncanville, TX - USA
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
I think the difference in the(fact.) kpm/mph speedos is just the printing on the face, and possibly the speedo gears themselves? Not really sure...
If you change to a higher range speedo, there may be a different board required, or maybe just a different resitor/shunt in the system.
If you have a supplier for the new speedo, you might need to ask if there are other mods/parts needed.


Joel Adams
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Speedo Circuit Board

Posted: 9/7/06 6:52pm Message 3 of 8
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CUYAHOGA FALLS, OH - USA
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Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

In a 1980?  Look close.   The speed is still cable driven.  The printed circuit board should not have any affect on the speed reading.  The difference is the calibration of the speedo head ( mechanical ) and the different face.

Some California speedos have a VSS, vehicle speed sensor, and all 81 have  the VSS as part of the speedo assy.  So the head is different but the calibration is still mechanical.




Speedo Circuit Board

Posted: 9/7/06 7:04pm Message 4 of 8
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Wow!! Good catch on that one, Ken!


Joel Adams
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Speedo Circuit Board

Posted: 9/8/06 12:21pm Message 5 of 8
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Frederick, MD - USA
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Vette(s): 1969 convertible L71 427/435 4-speed black interior
My '78 came with a metric speedometer. I swapped it out with a 140 mph speedo head and used the same printed circuit...no problem at all. I do think the speedometer reads a bit higher than is accurate, but not a lot. The tires are one size undersized (P245/60R-15 instead of P255/60R-15)), which may account for that. The tires were new on the car when I purchased it so I'm not going to spend for a new set just because of that.


Speedo Circuit Board

Posted: 9/9/06 9:09am Message 6 of 8
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Canada
Joined: 10/2/2005
Posts: 164
Vette(s): 1980 Black on Red with 383 Stoker 4 speed. T-Tops

Thanks a bunch guys for the info. Much Appreciated  

T




Speedo Circuit Board

Posted: 9/9/06 9:18pm Message 7 of 8
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
[QUOTE=kstyer]

In a 1980?  Look close.   The speed is still cable driven.  The printed circuit board should not have any affect on the speed reading.  The difference is the calibration of the speedo head ( mechanical ) and the different face.


Some California speedos have a VSS, vehicle speed sensor, and all 81 have  the VSS as part of the speedo assy.  So the head is different but the calibration is still mechanical.

[/QUOTE]

Therefore, if you install a "normal"(not metrical) speedo head, it should be properly calibrated...

The 81-82's had 'lectrical speedos for the lock-up convertor to work. It needs a valid speed signal. The Calli cars got the 350lu in '79 or 80.


Joel Adams
C3VR Lifetime Member #56    

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(click for Texas-sized view!)
             NCRS

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Speedo Circuit Board

Posted: 9/10/06 7:00am Message 8 of 8
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Canada
Joined: 10/2/2005
Posts: 164
Vette(s): 1980 Black on Red with 383 Stoker 4 speed. T-Tops

Thanks guys, you da bomb   

T




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