Slow speedo

[MrIan]

Hi,
Just as an aside, great car!
Best wishes,
Mike.

Yes I thought the same thing !!

[errolflyn]

thank you Mike yours too

[bmcecosse]

That is certainly a pudding stirrer, but it may be on a 948 gearbox. Although the speed is wrong - how accurate is the odometer? Can you check against a known distance ?

[errolflyn]

I think thats ok and is certainly is moving but not sure if its right

[mike.perry]

The speedo 1600 TPM is for a Series MM with a 4.55 final drive. The 803 speedo TPM is 1000 for both the small and centre dash speedos with both the Morris and A series 5.375 diffs. The gearbox looks like the standard Series II 803 box.
So to summarise, with an 803 gear box and diff you should have a speedo X70620/7 1000

[errolflyn]

Really where am I going to find one of them

[mike.perry]

Try MMOC Club Spares or Nat. Rally

[MrIan]

Wasn't there a member on here that made small gearboxes to fit behind the speedo to sort gearing isseus for the speedo drive ?
I'm sure I remember reading a thread about them. Small gearboxes that fitted to the speedo cable fitting then you fitted your speedo cable to them and they adjusted the ratio.

[MrIan]

In this thread - http://www.mmoc.org.uk/viewtopic.php?f= ... ox#p548067

[errolflyn]

thanks for your help again , I spoke to the company that delt with it today he told me send the speedo back and more info and he recons he can do it so if he can that would whole lot easier than searching for another

[bmcecosse]

| was just thinking the same -that really a 1000 tpm speedo is what would originally be fitted to this car - NOT a 1600 tpm. However since you appear to have a later lower ratio final drive - you will need to find something like 800 tpm to get it reading correctly - and I think that is going to be unlikely. This also ties in well with your reported 'double speed' readings. Worth trying Declan - although not sure he will be able to get you gears for a 2:1 increase . But maybe!

[mike.perry]

Small speedos are only available in 1000, 1600 or 1650 (Morris MS) The 948, 1098 and 1275 boxes use the same gear and pinion ratio so swapping speedos is straight forward. The Series MM and Series II have different gears so just swapping to a different speedo will not work. From experience I have found that fitting a 1000 TPM speedo to a Series MM will give in indicated speed nearly double, therefore the reverse would apply if you use a 1600 TPM on a Series II

[errolflyn]

So are you saying that if I put a 1000 speedo on it it will work at the moment it's a 1600 and your right it's only showing half the real speed

[mike.perry]

If you have an 803 gearbox and diff then a 1000 TPM speedo will be correct

[bmcecosse]

NOT with that final drive ratio !! You need ~ 800 tpm.

[Boomlander]

I have a 948cc engine mated to a pudding stirrer, non remote gearbox and my 1000 TPM speedometer consistently reads 10mph higher than the actual speed.
Although I can happily live with this, when the time comes would there be an advantage to fitting a later gearbox as the final drive also appears to be not the original to a 1953 Series II.
Thanks as always for your thoughts and advice. [frame][/frame]

[liammonty]

Boomlander - This has been covered a lot over the years, but if you change to a later gearbox, your 1000 rpm speedo will be hopelessly out, ie it will over read by at least 50%. To counter that, you will need to dismantle the box and change the gear on the 3rd motion shaft that drives the speedo drive gear assembly itsel , which will of course also need changing.

If you are just planning to change final drive, to say 4.55, that will more r less correct your current 10% over read on the current set up, assuming it's still the standard 5.375:1

[errolflyn]

I've just found someone selling a 1000 speedo he's sending it so I can try before I buy which was good of him , he has 2 spare ones and has the same car as me he tried on his And it worked properly so I'm hopping it will on mine

[liammonty]

Good luck! It should be far closer than your current one.

[errolflyn]

Thanks for all your help I've just bought a 1000 speedo of eBay and just fitted it now it's perfect I just wished I asked on here before I wasted £100 on getting the other repaired