Wondering if Spit has the right diff fitted?

[cliff.b]

6 minutes ago, johny said:

I thought the needle was pretty well fixed - it certainly didnt want to come off easily and I didnt want to force it as thought it might upset the disc to magnet distance...

If & when I get around to opening it up I will share what I find. I have lots of other things to look at so may be some time.

Got used to sticking phone in ashtray hole & looking at GPS app for now, when I actually get to drive the car instead of doing work on it lol

[Mad4classics]

It is possible to calibrate a Speedo or tacho yourself if you fancy; requires patience.

The attached document covers many different old speedos, but gives a good flavour of what's required.

First thing is to give it a good clean and oil; clock oil is good for this because it's very light.

Something to ponder if you're not in a rush to do anything.

David

 

TM9-1829A.-SpeedoRepair.pdf

[cliff.b]

3 minutes ago, Mad4classics said:

It is possible to calibrate a Speedo or tacho yourself if you fancy; requires patience.

The attached document covers many different old speedos, but gives a good flavour of what's required.

First thing is to give it a good clean and oil; clock oil is good for this because it's very light.

Something to ponder if you're not in a rush to do anything.

David

 

TM9-1829A.-SpeedoRepair.pdf 15.65 MB · 0 downloads

Many thanks. Maybe something to keep me occupied next Winter lol

[Pete Lewis]

i would never take the needle off as this lets the hairspring go free and getting that back to the

right tension is pretty impossible 

smiths needles are a light press on fit so holding the disc and lightly rotate the needle on its spindle should work without complications 

take care you can snap the needle pointer off it centre

I had a genuine  smiths tester with huge electro magnets for de gauzing or remagnetising the rotor  ,  with a powerfull and highly variable TPM counter 

it went in the skip  ,,,pity  a bit big for homework 

http://obswww.unige.ch/~wildif/cars/docs/Smith-jaeger_speedo_repair.pdf

here is some detailed clues not all are as i see this but its pretty informative

into what can or should not be attempted 

and something to digest while the TV is rubbish 

Pete

[cliff.b]

1 minute ago, Pete Lewis said:

i would never take the needle off as this lets the hairspring go free and getting that back to the

right tension is pretty impossible 

smiths needles are a light press on fit so holding the disc and lightly rotate the needle on its spindle should work without complications 

take care you can snap the needle pointer off it centre

I had a genuine  smiths tester with huge electro magnets for de gauzing or remagnetising the rotor  ,  with a powerfull and highly variable TPM counter 

it went in the skip  ,,,pity  a bit big for homework 

http://obswww.unige.ch/~wildif/cars/docs/Smith-jaeger_speedo_repair.pdf

here is some detailed clues not all are as i see this but its pretty informative

into what can or should not be attempted 

and something to digest while the TV is rubbish 

Pete

Many thanks. I'm getting inspired by the challenge of sorting this out now 🙂

[Pete Lewis]

at risk of repeat   just hold the disc and  move the needle a few mph on its spindle   easy when the calibration  error is consistent 

turn the needle by its centre , not poke the needle , metal needles are better plastic ones 

can snap the needle off its centre 

Pete

 

[Mad4classics]

I built a heath-robinson magnetizer which I've used on several instruments with success when the error is a percentage of the reading shown.

Makes a good winter project!

For a fixed offset across the whole range, you just need to move the needle as Pete indicated.

David

[cliff.b]

Many thanks all 👍