Help on odometer repair

[AlexJ]

Hi all and Merry Christmas,

My odometer on my 1982 SC never works and today I decided to repair it.
Here is how it looks like:



I just bought what was supposed to be the broken gear from a Porsche parts retailer here in the Island:



After disassembling all the parts, it was obvious which gear was broken

[Mike80911]

There is a really great write up in the tech info center on fixing the odometer gear explains everything step by step

[AlexJ]

The old gear was in pieces in the case and it was obvious to me that the gear has been over heating probably due to friction on the shaftt - lack of lubrication (??)

I just through: that is simple! It is done!
I was wrong...

The new gear doesn't fit. The big teeth on the new gear fits well on the electric motor shaft but the inner gear doesn't fit the white gear's teeth... Sems like the inner rings is bigger than it should be...







In my opinion, there are two chances:

- the new gear is wrong size for my odometer;
- the over heating changed the position of the shaftt...

I have been forcing the shaftt a bit to make the new gear fit the white one and already crack the plastic part that holds the shaft in two places as you can see:



Now, I need some advise:

Is there another gear size? I have seen this somewhere in the web but all of them say it should be used on MPH odometers...

I think that if there is another size, the cracks on the plastic piece won't be so important because it should not work under big force... I probably be able to reinforce the plastic part grooving the cracks a bit and filling it with glue... Or should I try to buy a used plastic part?

I would like to have some opinion from those who have experience on this subject.
Thanks in advance.

[AlexJ]

Originally Posted by Mike80911

There is a really great write up in the tech info center on fixing the odometer gear explains everything step by step

Yes, I have seen it but it is not the same type of odometer.
Thanks anyway.

[Sigurd]

Can you please let me know the number of teeth on the different gears? I have a mph one I need to convert to km/h.

Thanks

[AlexJ]

20 outside and 30 inside. The lat number can be wrong because teeth are very small and my eyes are a bit tired... yes, I count again and it is 30!

[boyt911sc]

Originally Posted by AlexJ

Yes, I have seen it but it is not the same type of odometer.
Thanks anyway.

Alex,

You have done the most critical steps of the project and re-assembly is the reverse procedure. However, if you have the right gear replacement, you should have no problem about alignment. These are the pictures of the odometer gear replacement I did a couple months ago.









I could not have done this project without reading the posts of other members about odometer replacement and their suggested techniques. Keep us posted.

Tony

[AlexJ]

Here is another pic to show why the new gear doesn't fit:

[AlexJ]

Originally Posted by boyt911sc

Alex,

You have done the most critical steps of the project and re-assembly is the reverse procedure. However, if you have the right gear replacement, you should have no problem about alignment. These are the pictures of the odometer gear replacement I did a couple months ago.









I could not have done this project without reading the posts of other members about odometer replacement and their suggested techniques. Keep us posted.

Tony

Thanks boyt911sc but my gears are different than yours... I think it is because yours is in MPH which makes sense. The only similar gear you have is the one on top - mine is black but looks the same 20 big tooth and 30 small ones...

I am really confused...

[boyt911sc]

Originally Posted by AlexJ

Thanks boyt911sc but my gears are different than yours... I think it is because yours is in MPH which makes sense. The only similar gear you have is the one on top - mine is black but looks the same 20 big tooth and 30 small ones...

I am really confused...

AlexJ,

The odometer gears come in different spec:
Green............20/29 count.
White............20/30 count.
Black.............20/32 count.

Based from the other postings by people who previously made the gear replacement, SC and Carrera 3.2 odometers would need a 20/30 count. Maybe someone who has done the odometer gear replacement involving metric reading would chime in. I thought only the faces (KPH or MPH) of the speedometer is different and have similar gearing (???). Anyone has used the black odometer gear (20/32)?

Tony

[A horse with no name]

Hi... I just purchased and installed the correct odometer gear (pelican) for my3.2 in kms. Here is the part number including gear numbers.

ODO-POR-20-22 $25.00 1 $25.00
Porsche Odometer Gear, 20x22 Tooth Gear, each

My 20X22 was/is white.

Pelican -> 911 Euro-KM and Asian (Base, Carrera, SC, Turbo) 1975-1989 *20x22 or 20x32 ODO-POR-20-22 or ODO-POR-20-32

Hope this helps to resolves it for you.

PS- I found that by putting an elastic band over the speedometer and the motherboard it was much easier to lower the unit back into the housing- Just cut the elastic band once in and then just pull it out from the top.

[AlexJ]

Thanks no na,e horse.
I will check that.
BTW, nice idea on the elastic band!

[A horse with no name]

Your welcome!... After I started mumbling after numerous failed attempts the cliché "Necessity is the mother of invention" came to fruition

[dshepp806]

To the OP: Sounds like wrong gear...

Doyle

[SCOTITUDE]

the repair not worth the aggravation.

1- box up speedo
2- mail to North Hollywood Speedo
3- wait patiently, have a cocktail
4- box returns in a couple days
5-open box
6-install fixed speedo
7- smile

waaaayyyyy less of a PITA.

North Hollywood Speedometer and Clock Company. Serving your gauge needs since 1955. VDO, Porsche, Mercedes, BMW, Volkswagen, Veigel, Veglia