S3 OD Speedometer.

[Mike O'D]

Anyone have one they would be willing to part with?

Thanks.

Mike

 

[DanR]

Mike, I may have one? What the numbers on yours?

 

[Mike O'D]

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

 

[65beam]

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.

 

[hartmandm]

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

 

[alpine_64]

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.

 

[Mike O'D]

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.

 

[hartmandm]

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

 

[65beam]

Maybe

Thanks for all of the responses guys - good info.

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.

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.

 

[Mike O'D]

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.

 

[Mike O'D]

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!

 

[Alpine 1789]

Series V OD with 4.22 rear is 1504 turns per mile...That is all assuming stock diameter tires.

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.

 

[junkman]

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!

 

[alpine_64]

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

 

[junkman]

Thanks Michael, I will have look this week.

 

[Mike O'D]

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

 

[hartmandm]

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

 

[Tom H]

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

 

[alpine_64]

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

 

[hartmandm]

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