Please help modify 930 odometer from mph to kmh

[ornas]

Recently my odometer stoped working, so I decided to modify my speedometer from mph to kmh. I have sourced km/h gauge bazzel localy, but do not know what to do with gears. Could someone tell me what gear should be changed to make odometer turn in km?

[jimbeaux911]

no need to change any gears. Km/h is proportional to mph. the new faceplate is the only thing that needs to change.

many dials have both, with only one set of gears.

[ornas]

Changing face plate is an easy part, but I want to make odometer turn in km, not in miles.

Originally Posted by jimbeaux911

no need to change any gears. Km/h is proportional to mph. the new faceplate is the only thing that needs to change.

many dials have both, with only one set of gears.

[universeman]

Contact North Hollywood Speedo.

[E900]

Originally Posted by ornas

Changing face plate is an easy part, but I want to make odometer turn in km, not in miles.

He's saying the layout of the mph faceplate is the same relative to the speed as the kph one is. So if the needle is at 62 mph, and you would drive the same speed the kph faceplate would say 100 kph.

[sc_rufctr]

You have to change a gear in the mechanism...

Start here. http://www.odometergears.com/documentation/Porsche_911_20_x___Odometer_Gear_Replacement.pdf

But you have to know how many teeth you need for kms. Sorry can't help on that.

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

[porschetub]

Originally Posted by ornas

Changing face plate is an easy part, but I want to make odometer turn in km, not in miles.

Been thru this myself,correct on what you say,miles read @ a differant geared rate to kilometers,our crazy government made you put a sticker over the speedo in your european car years ago because they deemed the public too dumb to work it out for themselves that they couldn't work metric to imperial conversion .
I get tired with replies like send it to NHS when it isn't an option due to cost/exchange rate or location,in my case I have been talking with Howard Instruments in Australia they have a full service for Porsche VDO.

[ornas]

On rennbay they say
"1974 - 1989 Km/h Gages - Most use the 20x21 tooth gear but some still used the 20x30 tooth gear. You must count the teeth on your old gear to be sure. It will be one of these two gears. "

This makes me a bit confused, couse i thought that secondary must rotate 1,6 times faster, but 20x21 gear would require larger secondary gear that would couse even slower odometer rotation

I have asked nhs if they could sell me a mph/kmh conversion kit, but they did not respond.

[A horse with no name]

Originally Posted by ornas

Recently my odometer stoped working, so I decided to modify my speedometer from mph to kmh. I have sourced km/h gauge bezel localy, but do not know what to do with gears. Could someone tell me what gear should be changed to make odometer turn in km?

Hi, our host sells them:

911 Euro-KM and Asian (Base, Carrera, SC, Turbo) 1975-1989 *20x22 or 20x32 ODO-POR-20-22 or ODO-POR-20-32 n/a n/a *Must be confirmed prior to ordering.

[ornas]

Any ideas where I can source the secondary gear?

[A horse with no name]

[QUOTE=ornas;8663916]Any ideas where I can source the secondary gear?[/QUOTE

I believe that our host does. Use their ' contact' form and ask them

[ornas]

[QUOTE=A horse with no name;8663980]

Originally Posted by ornas

Any ideas where I can source the secondary gear?[/QUOTE

I believe that our host does. Use their ' contact' form and ask them

Pelican has only primary gear

[A horse with no name]

Try North Hollywood Speedometer and Clock- They have been in business since 1955 . If anybody has or knows where to source one I would they would.
Here's there link.

info@nhspeedometer.com

[ornas]

Found out that difference is in electronics, gonna try to make an adapter

[psychoideas]

Originally Posted by ornas

Found out that difference is in electronics, gonna try to make an adapter

Old thread I know, but did you ever get a solution to this?

Cheers,
Frank

[7783911]

contact JBELL on this forum...does geat work

[pkabush]

Another shout out to Jbell. Great communication, quick turnover and very reasonably priced

[jbell959]

Originally Posted by psychoideas

Old thread I know, but did you ever get a solution to this?

Cheers,
Frank

The board is the same for both but all 3 gears need to be changed and it will need to be recalibrated. The earlier ones have a potentiometer on the board to allow for calibration, but the later ones do not. On the later ones you need to replace one of the resistors with a potentiometer to do this conversion.

I haven't bought the conversion gears in a while but there was a place in Germany that was selling them. That was the only place I could find them at the time.

[Daugaard]

This:
https://www.ebay.de/itm/392162988622?fits=Make%3APorsche&hash=item5b4ebc524e:g:nLoAAOSwvOdhzG57
From miles to km/h

[jbell959]

Originally Posted by Daugaard

This:
https://www.ebay.de/itm/392162988622?fits=Make%3APorsche&hash=item5b4ebc524e:g:nLoAAOSwvOdhzG57
From miles to km/h

Yep... Those are the correct gears