Speedometer & Odometer calibration

[JagTheOne]

Hi guys, I would like to change in the future my diff ratio from 3.54 to 3.07 and change the units from miles to kilometers thus I will need to calibrate my speedo.

The question is: who cares? sorry...

No, the question is... What are the options?

1.) I can send my speedo together with all necessary data to someone and they will do it for me. (they will change just gears in the speedo)

2.) Can I change the speedo drive gears in the gearbox? The angle drive gearbox for speedo will stay the same.

[Heuer]

You could either have the speedo re-calibrated or find the correct one s/h. Serial numbers of speedometers here: http://etypeuk.com/forum/viewtopic.php?t=951

If you want your existing speedo serviced and re-calibrated:

Speedograph Richfield (instrument restoration/calibration): http://www.speedograph-richfield.com/
Speedy Cables (instrument repair, restoration, calibration): http://www.speedycables.com/index.html
Speedometer calibration: http://www.westnet.com/~mfrank/Speedometer/Smiths.html
John D Ostick (instrument repairs, re-calibration): http://www.jdo1.com/

[JagTheOne]

Thanks David! I didn't mentioned the third option of correct speedometer because I hit Submit button instead of Preview

Now I have next question... How accurate is that database?

There is: SN 6322/03A; xxxx; 3.31; mph; 6.40x15 SP41

This is the number on my speedo with 1312 TPM. But I have 3.54 diff wich is according to Jaguar certificate original.

So I will have to look for speedo with Kmh face but with wich serial number or TPM...

[vee12eman]

Hi,

I know this doesn't help with the speedo calibration, but you can change a speedo to km/h just by changing the face - available from SNG. The odometer still reads in miles of course. I don't know whether the calibration people will re-paint the face of the speedo, so if you want a km/h face, this may be an option.

Regards,

[JagTheOne]

Thanks Simon, I know about that. I will probably find correct speedometer and restore it.

[abowie]

I sent mine to Speedograph in Nottingham. If you look on their website they ask for a whole lot of information about your car to correctly calibrate it; cost me about 70 pounds plus postage. The guy I spoke to on the phone was a bit grumpy to deal with.

As I haven't yet finished putting my car back together again I can't comment on accuracy but it is certainly very clean.

[Pavel Prochazka]

Hello all,

I have currently car dismantled and thus cannot verify the turns as described in Richfield's form. Should you please provide me with your numbers of cable turns per 6 drive wheel turns (as they recommend "push car for 6 wheel turns and count cable turns") I have calculated mine for 3.54 differential and 1.25 gearbox angle drive and I got number around 10 1/8. What were your results, preferably for 3.54 differential but other differentials are welcome as well.

Many thanks to all for your help,

Pavel
Dec1966 LHD OTS 4.2

[Heuer]

Pavel

Have you checked out the list in this post?: http://etypeuk.com/forum/viewtopic.php?t=951

[JagTheOne]

Nazdar Pavel,

I have a Series 1 4.2 FHC with 3.54 diff. The TPM on the original speedo is 1312.

Martin