TRIUMPH HERALD SPEEDO

[foshi]

 not sure on correct listing but , speedo not working just found snapped gearbox end , rerun a good spare to the speedo gave it a turn at the gearbox end but not moving seems stuck solid,  obviously will snap if i connect up to the gearbox can the speedo drive seize at the speedo paul

[johny]

Cant see any reason why the speedo couldnt seize. I would have thought its unusual but suppose the internals can dry out as they never normally get lubed....

[Colin Lindsay]

Easiest way to check is to disconnect the cable from the speedo and see if it turns as the car moves; then do the opposite, insert a cable into the speedo and spin it with your fingers - the needle should move. (Or have you done that? Just reread the post!) 

Replacement speedos are relatively easy to get; avoid the 'NOS' ones from upwards of £90 or so (up to a massive £199 currently!), new ones come up at a more reasonable £30 or so every so often and at present there are a few used versions on eBay starting at a tenner. 

[johny]

Buy a replacement! What are you saying sir - this one can come apart, be freed off (maybe🤔), lubed and put back in service. Honestly nothing sophisticated in there although if you have to start actually dismantling the mech it will get more complicated....

[foshi]

ok so seems like speedo is the problem will have a good look at that  its from a 13/60  has a vitesse dash fitted paul

[foshi]

just to make sure i am right in thinking with the gear box end removed and i turn the cable the speedo should flicker at present will not even move cable solid .remove from speedo turns freely .

[johny]

yes thats pretty conclusive unless the cable somehow jams as you do it up into the back of the speedo. That is possible although the way you found the old cable broken at the gearbox suggests it was all working ok until the speedo seized...

[Colin Lindsay]

19 minutes ago, foshi said:

just to make sure i am right in thinking with the gear box end removed and i turn the cable the speedo should flicker at present will not even move cable solid .remove from speedo turns freely .

If you gently rotate / shake the speedo, does the needle move about?

[foshi]

just been out if i shake the speedo the needle moves 

[foshi]

the cable looks the same as the broken one length wise part that  goes into speedo ,seems to slot in fine then screws up as it should ?

[johny]

Fraid its got to be the bearings where the drive enters the speedo. Apart from driving the mileage counters it also spins a magnet located very close to a disc which can rotate but is restricted by a spring. The faster the magnet spins the more the force applied to the disc by the magnetic field so the disc turns against the spring and moves the needle round.

Hopefully with a bit penetrating oil (dont get it everywhere) and patience the bearings might free off...

[johny]

Actually Colins probably right about getting a replacement speedo unless you enjoy a challenge. When theres items like this available it makes sense:

TRIUMPH HERALD 13/60 "SMITHS" SPEEDOMETER--4.11 DIFF READING | eBay

[foshi]

thank you going to have a go freeing it tomorrow if not then a good used i feel is the way to go .

[johny]

Are you going to try with just a bit of oil in the drive first or go straight to opening up the unit?

[foshi]

left some light oil socking overnight see what happens 

[Pete Lewis]

do not ever take the needle off or the hair spring will unwind and you have no idea where to reset it to

if you have to strip it right down  mark the disk and needle repationship (hair spring turns ) to have some hope of getting it back together

the small pawl and lever that indexes the oddometer rolls is worth a dab of oil 

freeing the main spindle is not easy 

you may end up sending to speedy cables or JDO   for refurb.

[DanMi]

I used https://www.classicsparesengineering.co.uk/classic-spares-services to repair my speedo a few years back, they did a good job at a fair price

[foshi]

had a go today seized solid , looking at it it is different from the herald  13/60 hole for main beam screw type mileage counter , any idea what car it came from . paul

[foshi]

may have to get in touch with them danmi. 

[Colin Lindsay]

I'd guess that one is early Spitfire, possibly Mk1.

[DanMi]

a 110 mph speedo would either be spit mk1-2 or vitesse. If vitesse it may well be for the wrong diff ratio what is the turns per mile a number above right of the centre of the needle, should be 1248 for the 4.11 and 1182 for 3.89 if my memmory is working. My guess is that it is vitesse as it has the voltage regulator attached, early spit does not

 

[Colin Lindsay]

I reckoned it wasn't later Vitesse as they only have two warning lights along the bottom, not three. Spits have three!

[NonMember]

I don't think it's from a 2L Vitesse as I'm pretty sure they were 120mph speedos. Could be a late 1600, perhaps. As for the voltage regulator, I'm pretty sure my Mk3 Spit has it there (but, again, marked to 120mph) but I'm not sure on Mk2

[Colin Lindsay]

Spitfire Mk1 gauge:

  

 

[johny]

yes although cant see screw hole for volt reg, but easy to do...