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S3 OD Speedometer.

Discussion in 'Alpine Cars and Parts Wanted' started by Mike O'D, May 6, 2020.

  1. Mike O'D

    Mike O'D Gold Level Sponsor

    Anyone have one they would be willing to part with?

    Thanks.

    Mike
     
  2. DanR

    DanR Diamond Level Sponsor

    Mike, I may have one? What the numbers on yours?
     
  3. Mike O'D

    Mike O'D Gold Level Sponsor

    I'll check and let you know - thanks Dan.
     
  4. 65beam

    65beam Bronze Level Sponsor

    I hope Dan can help. I contacted Nisonger about rebuilding and restoring the speedometer for the LeMans and they suggested I buy a cheap Garmin due to cost of the rebuild or switching it to a GPS unit. I seem to remember $700 plus either way.
     
  5. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    Mike O'D - what is your situation? Are you adding an OD gearbox to a car that was not originally OD? Or looking to replace an existing series 3 OD speedometer that is broken or in poor condition?

    Mike H
     
  6. alpine_64

    alpine_64 Donation Time

    The series 3 OD speedo was unique as it was geared for 3.89 and OD.

    Another unique part for a series 3 OD car is the light switch it has a resistor on the top tgat wgen the OD is engaged with the panel lights on it dims the also unique faceted opal od warning light.
     
  7. Mike O'D

    Mike O'D Gold Level Sponsor

    Thanks for all of the responses guys - good info. Dan - I can read SN532 on the left side and 1000 on the right. According to the parts book, the S3 non-OD speedo is SN5324/16. It's possible that the 4 is covered up by the needle, but I don't see a 16 anywhere on the face. The OD speedo is the same number except /18, according to the book. Picture of mine is attached.

    Mike H. - I am running a 1725 with full syncro trans with OD and original 3.89 rear end. Car was originally non OD, and I am using the original speedo. It's reading high (as expected) - almost exactly 20%.

    Alpine 64 - that brings up something I hadn't thought of - will the S3 OD speedo read correctly with the full syncro OD tranny?

    65beam - It's not a huge problem doing the conversion to correct the speed that I'm traveling, but it would also be nice to have it reading correctly (or close enough to it). I refurbish all of my own instruments (all of the other parts too, now that I think of it) except the tach - thanks Tom H.
     

    Attached Files:

  8. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    See http://wp.mhartman.net/home/cars/sunbeam/alpine/gauges

    Series V OD with 4.22 rear is 1504 turns per mile. Series IV OD with 4.22 rear was around 1530 turns per mile. You could have a late series IV OD or series V OD all-synchro.

    S3 OD with 3.89 was 1408 turns per mile. Mixing later OD with 3.89 rear should be somewhere around 1386 turns per mile. 1386 vs 1408 is only 1.6% difference. That is all assuming stock diameter tires.

    3.89 vs 4.22 rear is 8% difference. I'd expect your 20% high reading to be even higher - maybe 28% ??

    Using your existing speedo with a gear reducer is an option, too. I remember finding some options via Google.

    Mike
     
  9. 65beam

    65beam Bronze Level Sponsor

    Maybe
    I understand that it's not a big problem. I retired several years ago but I still work for the company, have my own business and other things that keep me going for sometimes 16 to 18 hours a day. I don't have time for a lot of things I used to do when I was younger. There's something wrong with that. I do have one Sunbeam with a speedometer and fuel gauge but the others are idiot lights.
     
  10. Mike O'D

    Mike O'D Gold Level Sponsor

    Sorry Mike - for some reason 20% was stuck in my head - it's actually more like 36%. 62 mph indicated is 40 on the GPS. I'll check into the gear reducer option as well. Thanks.
     
  11. Mike O'D

    Mike O'D Gold Level Sponsor

    I could have someone else do it, I just really enjoy taking things apart, seeing how they work inside, and fixing them. It's a sickness!
     
  12. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    FWIW, I have a SV OD/1504 speedo on my car with a 3:89 rear and 14" tires. The combination actually works out pretty well and my speedo reads reasonably accurately.
     
  13. junkman

    junkman Gold Level Sponsor

    If one of you guys has a # from the face of the correct speedo, I'll check my pile of Alpine speedos. Never know what's in there!
     
  14. alpine_64

    alpine_64 Donation Time

    I believe the S3 od speedo SN number is: 5324/18
     
  15. junkman

    junkman Gold Level Sponsor

    Thanks Michael, I will have look this week.
     
  16. Mike O'D

    Mike O'D Gold Level Sponsor

    Thanks for all of the input guys, please let me know if anyone finds one in their piles of stuff.
     
  17. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    Are you sure about the 40 mph actual being a 62 mph speedo reading? The speedo would be reading 55% high. Are you sure you have a 3.89 rear?

    Mike
     
  18. Tom H

    Tom H Platinum Level Sponsor

    Mikes, ( Hartman and O'Donnell that is)

    Hartman posted:
    Series V OD with 4.22 rear is 1504 turns per mile. Series IV OD with 4.22 rear was around 1530 turns per mile. You could have a late series IV OD or series V OD all-synchro.

    And S3 OD with 3.89 was 1408 turns per mile. Mixing later OD with 3.89 rear should be somewhere around 1386 turns per mile. 1386 vs 1408 is only 1.6% difference. That is all assuming stock diameter tires.

    Is this all really true? That the S3, SIV, and SV OD's each have a different OD ratio? Or a different Speedo output Gear? or used different Tire diameters??

    O'Donnell's car is an amalgam of body, engine, tranny, OD, wheels, and tires from different Alpines. I did not think that the OD's were different between Series. And I'm not sure Mike knows what series the OD is really from, if it really matters.

    Tom
     
  19. alpine_64

    alpine_64 Donation Time

    There a whole bunch of speedo input and cable gears that could easily throw a speedo... I know i intially screwed up the maths mixing and matching when i put a SV od box in my SII with 3.89 and 195/65/14s.... But there was enough asjustment after a switch out of the gears to get it quite close between the 40-60mph range
     
    Last edited: May 12, 2020
  20. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    Based on the rear axle ratio and speedo turns per mile, the OD ratios across series 3, 4, and 5 calculate to within 1.5% of each other. Hence, I'd assume the ODs had the same ratio.

    Mike
     

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