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| Speedo calibration https://slantsix.org/forum/viewtopic.php?t=45727 |
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| Author: | raycycled [ Mon Jul 25, 2011 9:42 pm ] |
| Post subject: | Speedo calibration |
Is there any way of calibrating an A body speedo ours is out by 7 or so MPH and we got a speed camera fine last month ? RAYCYCLED |
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| Author: | Joshie225 [ Mon Jul 25, 2011 10:32 pm ] |
| Post subject: | |
Check to see if the odometer is correct. If not you need to change the speedometer drive gear in the transmission. If the speedometer is still not correct it has to go to a shop that does speedometer calibration. |
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| Author: | Fopar [ Mon Jul 25, 2011 10:33 pm ] |
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Also for speedo gears http://www.mymopar.com/speedometer.htm Richard |
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| Author: | raycycled [ Tue Jul 26, 2011 3:06 pm ] |
| Post subject: | |
Thanks Richard, is the Diff ratio stamped some where on the out side of the housing? RAY |
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| Author: | wjajr [ Wed Jul 27, 2011 12:11 pm ] |
| Post subject: | |
To determine which speedometer gear is needed you have to find rear end http://www.slantsix.org/forum/viewtopic ... gear ratio, and know the size of your rear tires. Look on this chart at Year One to see which speedometer gear is right for your drive train combination. Remove your present speedometer gear per FSM and make note of orientation of its clamp as there are three positions depending on gear used. Than check its color, and number of teeth, and compare with Year One’s chart. When you reinstall the gear, be sure to clock its clamp correctly. If you need to change your speedometer gear, search the web for best price. |
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| Author: | Fopar [ Wed Jul 27, 2011 1:37 pm ] |
| Post subject: | |
1) Jack it up and do the turn and count. If it's open you only have to jack up one wheel. Put the car in neutral, and spin the tire one time while counting the number of times the driveshaft rotates. If it's open, double the number you get from the driveshaft rotations and that is the ratio (approximately). 1.3 turns for an open rear should be 2.76. 2) Pull the cover off the rear and find the ratio stamping on the ring gear. Richard |
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| Author: | raycycled [ Wed Sep 21, 2011 1:51 am ] |
| Post subject: | Speedo gear eqivalent |
Hi Ho guys been so long since I bought this subject up that I got a second speeding fine today #@^%$*&^ So I pulled out the speedo drive gear out, it is Blue and has 19 teeth and T19-2 on it, it is approx 1" in diameter, now I followed the links suggest in this thread but they are all way to big some of them have 42 teeth ? i calculate i need about 20 to correct my speed, it is a 3 speed manual column change, the cable and gear feed into the left hand side of the gear box when viewed from above, am I missing some thing obvious ??? RAYCYCLED |
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| Author: | wjajr [ Wed Sep 21, 2011 4:49 am ] |
| Post subject: | |
You may have miscalculated rear end ratio, or tire diameter the only two numbers one needs for selecting a speedo gear. |
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| Author: | 65 dartman [ Wed Sep 21, 2011 7:01 am ] |
| Post subject: | Re: Speedo gear eqivalent |
[quote="raycycled" . . . . So I pulled out the speedo drive gear out, it is Blue and has 19 teeth and T19-2 on it, it is approx 1" in diameter, now I followed the links suggest in this thread but they are all way to big some of them have 42 teeth ? i calculate i need about 20 to correct my speed, . . . . RAYCYCLED[/quote] Sounds like you have the early small style style speedometer pinion. The later ones are definitely larger and have anywhere from 25 or so to 42 or so teeth. The early ones are 1 inch or less in diameter and have at the most 21 or 22 teeth. You might be able to somewhat slow your speedometer down by changing size (diameter) of your rear tires. I forget if larger slows the speedometer down or smaller. Someone else might chime in on that. |
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| Author: | KBB_of_TMC [ Wed Sep 21, 2011 9:00 am ] |
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If I remember correctly, by design 2000rpm of the speedometer cable = 60 mph; from the ones I've seen, it's probably possible to adjust the spring tension *slightly* to change the speedometer reading relative to the cable speed - you'd have to do something like that if your odometer reads correctly, but the speedometer doesn't. |
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| Author: | SlantSixDan [ Wed Sep 21, 2011 9:55 am ] |
| Post subject: | |
We're a little off track on these suggestions just yet. First we need to know some basic info. What is the year and model of the car? What is the rear axle ratio? And what size are the tires? |
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| Author: | raycycled [ Wed Sep 21, 2011 3:18 pm ] |
| Post subject: | |
it is a 63 AP5 Valiant, speedo currently reads approx 9 MPH slower than what I'm traveling, if I have a Blue 19 tooth gear do I need to go up or down one size to correct it , RAY |
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| Author: | SlantSixDan [ Wed Sep 21, 2011 3:31 pm ] |
| Post subject: | |
Quote: it is a 63 AP5 Valiant
With rear axle ratio of ________?And tire size of ________? |
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| Author: | raycycled [ Wed Sep 21, 2011 11:16 pm ] |
| Post subject: | |
Sorry Dan dont know what the ratio of Diff is and didn't want to pull it apart to find out, but I figure if I Have a 19 tooth gear and need to speed up my speedo, one less tooth on the cable drive will do this ? RAY |
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| Author: | SlantSixDan [ Wed Sep 21, 2011 11:31 pm ] |
| Post subject: | |
Asking the same incomplete question again is not going to get you anywhere. You needn't pull anything apart to figure out the rear axle ratio; see here . And you certainly needn't pull anything apart to figure out the tire size. Help us to help you, by asking a complete question...please? Pretty please with sugar on top? 
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