Speedometer is driving me crazy- Something is Wrong

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1WildRT said:
Haven't read everyone's posts... So I might be repeating stuff.. Here goes..

First how is the odometer vs travelled distance... The odometer doesn't need the speedometer to be calibrated.... If the odometer is off your speedometer gear is wrong.... If the Odometer is accurate and the speedo is off the speedo needs to be calibrated...

The speedometer should read 60 MPH when the cable is spinning 1000 rpm
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So I did some testing today and it doesn’t seem like the speedometer is wrong.
Using a Photo Cell RPM meter and an old sears 1000rpm drill that actually runs at 1060 rpm (+10%) tested with the rpm meter.
I disconnected the Speedo cable from the transmission and hooked into the drill and ran it at full rpm (1060) for 2 minutes on a stopwatch with my buddy watching the speedometer and odometer. The result was a steady 67-68mph and a total of 2.2 miles.
Now I am wondering about the gear inside the transmission.
 
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-Boosted- said:
it was quite a bit smaller in diameter (don't know how many tooth) than the new gear.
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There are a number of gear diameters. If you look at the housing the gear goes in, the speedo gear is off set to accommodate different gear sizes. there are numbers around the rim of the housing that correspond with number of teeth on the gear and a nub on the transmission that acts as a pointer. You have to loosen the speedo cable nut on the housing to be able to rotate the housing.
 
str12-340 said:
There are a number of gear diameters. If you look at the housing the gear goes in, the speedo gear is off set to accommodate different gear sizes. there are numbers around the rim of the housing that correspond with number of teeth on the gear and a nub on the transmission that acts as a pointer. You have to loosen the speedo cable nut on the housing to be able to rotate the housing.
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Yup, I finally got it to go. The o-ring I had wasn’t the right one. Put the old o-ring back on and it slipped right in.
 
AZ-Nick said:
I disconnected the Speedo cable from the transmission and hooked into the drill and ran it at full rpm (1060) for 2 minutes on a stopwatch with my buddy watching the speedometer and odometer. The result was a steady 67-68mph and a total of 2.2 miles.
Now I am wondering about the gear inside the transmission
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At 1060 the odometer should read 2.12 miles. That you got 2.2 is close enough for horseshoes, hand grenades, and atomic bombs.

As for the 67 to 68 mph, that's a bit high 62 would be more like it at 1060.

1000/1060 is 6% fast, so 60mph at 1000 would be 63.6 at 1060.

So your needle is off by about 4mph.

With the correct gear you can make up for that or pull the cluster and adjust the needle.
 
Dana67Dart said:
At 1060 the odometer should read 2.12 miles. That you got 2.2 is close enough for horseshoes, hand grenades, and atomic bombs.

As for the 67 to 68 mph, that's a bit high 62 would be more like it at 1060.

1000/1060 is 6% fast, so 60mph at 1000 would be 63.6 at 1060.

So your needle is off by about 4mph.

With the correct gear you can make up for that or pull the cluster and adjust the needle.
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Thanks for your input, I just ordered a 44 tooth gear that should be sufficient. If it is too much then I’ll have to get the 43 tooth.
 
AZ-Nick said:
Thanks for your input, I just ordered a 44 tooth gear that should be sufficient. If it is too much then I’ll have to get the 43 tooth.
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I also got the scream of death the other day now speedo reads 20 sitting still. Got a 20 dollar gps speedometer that sticks on dash and projects speed on windshield. Problem solved
 
hepcat said:
I also got the scream of death the other day now speedo reads 20 sitting still
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Oh sorry to hear that. (pun intended)

I have the bounce of death till about 40mph then it mellows out.
 
I have had to change spedo gears several times along the way. I bought most of my gears from WWW.Speedometer Gear. Store from Kerry Conklin. The price is not bad and very fast shipping. Some of the gears i have from years gone by are not what they claim they are. In the circle of the gear is the number of teeth the gear should have and it is also color coded for fast id. But they are NOT all correct so after you put in the 40 tooth gear with no change with your needle reading. It might be that your gear is marked wrong. Count the teeth Just to be sure it is a 40. If it is i guess you can try the higher numbered gears you have said are on order. Should you need to buy more down the line , check out the gear store's price on them , maybe you could save a buck or two ?
 
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