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Speedo Questions - S1 sorta

Discussion in '"Stock" Alpine' started by woodybap, Feb 3, 2020.

  1. woodybap

    woodybap Silver Level Sponsor

    Well I finally got the car on the road. Ninety miles of far right lane freeway driving surrounded by 18 wheelers. A bit intimidating but oh so satisfying. There are 2 'adjusters' hanging from the speedo. One resets the tripometer. The other [at present] does nothing. Anyone know what it is for? Also replaced the speedo cable with one from SS that said SI-IV with OD. My car does not have OD. The indicated speed is out of whack. Could it be because I used the wrong cable?
  2. Gary T

    Gary T Gold Level Sponsor

    I do not believe the cable would change the speedometer accuracy, but the correct NonOD speedometer should be used. The OD speedometer is different than the non OD speedometer.
    woodybap likes this.
  3. alpine_64

    alpine_64 Donation Time

    The speedo cable for an OD is longer to reach the OD at the back. So its fine to use just make sure its not kinked due to the addtional length you will have.

    Re speedo accuracy...

    There are 2 speedos.. 1 for Od and non OD.. They take into account a 4.22 vs 3.89 diff Od v non.

    Also there are different gears for the drive that go in the gearbox... Depending on which ones you have the tooth count will change ratio ( like crown and pinion for a diff)

    Finally the speedo is geared for original rollimg radius of the factory wheels and tyres .. What size wheel and tyre have you got now?
  4. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    The difference between regular and OD speedo cables is the overall length of the cable. The length of the cable does not change the accuracy.

    Your speedo will list the revs per mile on the face. Double check it is 1000 or 1020.

    Speedo gauge info is available here: http://wp.mhartman.net/home/cars/sunbeam/alpine/gauges

    Can you clarify the 'out of whack'?

    If the speedo cable is binding, which can result from bends that are too sharp, you will probably see the speedo needle fluctuate between reading too high and too low.

    The needle moves based on the magnetic field generated by the spinning cable. Dirt inside the speedo around the needle pivot mechanism can skew the needle position. There are a couple speedo rebuild articles at: http://wp.mhartman.net/home/cars/sunbeam/alpine/info

  5. 65beam

    65beam Donation Time

    I've been driving Beams for close to 55 years. I have owners ask why I have the Garmin hanging on the windshield. It's not for directions.
    Paul A and woodybap like this.
  6. woodybap

    woodybap Silver Level Sponsor

    The tires are 185/13. I will be able to check the speedo markings in a few days.
  7. woodybap

    woodybap Silver Level Sponsor

    The speedo does not fluctuate but holds steady at about 10 mph below actual speed.
  8. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    10 mph reads as 0
    30 mph reads as 20
    60 mph reads as 50, etc?

    Or is the speedo reading off by the same percentage across various speeds?

  9. woodybap

    woodybap Silver Level Sponsor

    Seems more of a percentage thing.
  10. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    woodybap likes this.
  11. 65beam

    65beam Donation Time

    You're saying that the speedo is reading wrong and owners are jumping in with various comments of what could be wrong but you haven't mentioned what you're using to verify that the speed is reading wrong. What are you basing your comments on?
  12. woodybap

    woodybap Silver Level Sponsor

    My first inkling was simply by feel. Having driven the same roads in various cars for 50+ years I have some sense of speed and this just did not feel right. I then drove with a GPS to better gauge and verified there is a difference. The indicated speed is not the actual speed. My road home has 3 radar equipped speed signs that also confirmed the problem. I have not however documented the exact difference at each speed level. I have been hoping that this is a known issue with a simple fix.
  13. 65beam

    65beam Donation Time

    Since you used a GPS you're back to square one which means that the problem might be either tires or different rear gear ratio. It's very difficult today to find 13 inch tires which will match the diameter of the original tire and to source another good set of gears for the rear end. The speedometers in our series 4 and series 5 were repaired and recalibrated by Tiger Tom several years ago and both have tags on the back that tell the variance either plus or minus at different speeds. Same for my tachs. That's my reason for the GPS hanging from the windshield.
    woodybap likes this.
  14. Warren

    Warren Bronze Level Sponsor

    There is a simple fix,
    Never drive faster than it is safe too or feels good. The end of the oil interval clock be it seasonal or by mileage is what matters.
    I remember changing the cable changing the pinion and R and R ing the speedo hauling it down to a brick and mortar pro that's been there for as long as I can remember. Well after hundreds of dollars and in and out headstands under the dash it worked ok till the test drive on the car sale day. Then right after a " I have a receipt for all the work I didn't do including the speedometer it pegged and squealed like a pig. Naturally being a sales guy I went back to that's why the car is for sale I don't want to fix everything. That fix worked with regular weekend driving for about 2 years was past any warranty of the speedo shop...
  15. 65beam

    65beam Donation Time

    Everybody needs to take into consideration that the newest of these cars is at least 53 years old. That being said it's a known fact that things such as a speedometer were mechanical units on these cars. I can honestly say that not all imports of the 60's had a full compliment of gauges. I base this on owning several imports in the 60's and 70's. Like many cars of the era there was the wide spread use of "idiot lights". My 69 Alpine had a speedometer and fuel/temp gauges. I can also say that units such as speedometers could work correctly today but could also be useless a week later. That's the way it was and I have found that when having speedometers and tachs restored over the years I've been told that the lube was solidified. Todays cars depend on electronics to give you an accurate reading of speed where these originals don't. I contacted Nisonger while restoring the RHD LeMans and asked them about converting the original speedometer to electronic or for a better description to make it a GPS unit. They can do that but his comment was that considering the limited use of the cars would the starting cost of $700.00 up dependent on what was required to restore the face, etc be worth it. He said Garmins are a lot cheaper. They did convert the mechanical tach to electronic but unlike a GPS unit it has three wires so cost was a lot less. With todays drivers I prefer watching others around me rather than watching the gauges.
    Paul A likes this.
  16. alpine_64

    alpine_64 Donation Time

    Given you can buy a Tiger GPS speedo for half that price you could just do that and switch the faces. Even modifying for early series warning lights would be relatively easy.

    A well rebuilt speedo should last many years without issue. I had mine done in my alpine and was accurate to within 2% and i drove it daily for 10 years and never had an issue. Still in the car another 10 years later and still works well .. though no longer accurate to my car but thats because i went to 195/65/14 wheels... The gauge is still steady and out by the % of my wheels rolling radius.
  17. 65beam

    65beam Donation Time

    It all comes down to what the owner wants and there are many solutions out there. Ask questions and make a decision that fits your conditions, not the conditions of others.
  18. alpine_64

    alpine_64 Donation Time

    Right... So help the guy who asked the question rather than dragging a topic down many different roads... Which always seem to lead to the same location..... :rolleyes:
  19. 65beam

    65beam Donation Time

    It's difficult to find solutions without knowing all the facts and conditions. You can't assume and speculate.
    Paul A likes this.
  20. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    Let's see what additional details woodybap can provide and then go from there. I bet we'll have some suggestions to get his speedo readings more accurate.


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