Please help modify 930 odometer from mph to kmh
 

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?

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.

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

Contact North Hollywood Speedo.

:confused:

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.

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

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 :p:p.
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.

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.

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.

Any ideas where I can source the secondary gear?

[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

[QUOTE=A horse with no name;8663980] Pelican has only primary gear

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

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

contact JBELL on this forum...does geat work

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

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.

This:
https://www.ebay.de/itm/392162988622?fits=Make%3APorsche&hash=item5b4ebc52 4e:g:nLoAAOSwvOdhzG57
From miles to km/h

Yep... Those are the correct gears

So to get to odometer to work accurately you would need the gears to me changed as above. If you were to just change the speedo dial/faceplate from the MPH/KMH faceplate to the KMH one would it still read OK as the needle will still be in the same place throughout its range?

I looked into doing what you want to and the answers I got were not very assuring and confusing. I ended up sending the speedo to North Hollywood. Took about 4 weeks and had the speedo overhauled and converted. They also reset the odo to read the same mileage but in Km. The indicator is a weird color because of the light, they repainted it the correct red and the speedo looks great.

http://forums.pelicanparts.com/uploa...1641073174.jpg

What was the Ball park cost on that conversion?
I'd have to factor in the shipping cost from and to Australia

Thanks,
Frank

It depends on what MPH face you have and what Km face you are switching to. In most cases they don't line up exactly and require calibration.

I think I have a set of the conversion gears. If so, I can convert a working MPH speedo to Km including a new face, new gears, reset odometer, and restore needle and bezels for about $350.

Awesome, thank you.

BTW do you still do the AFR in the bottom of a Tacho?

Cheers,
Frank

Yep... Here is one I recently did for another Pelican.

http://forums.pelicanparts.com/uploa...1641087389.jpg