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Re: Slow speedo
Posted: Sun Jun 14, 2015 8:15 pm
by MrIan
jagnut66 wrote:Hi,
Just as an aside, great car!
Best wishes,
Mike.
Yes I thought the same thing !!
Re: Slow speedo
Posted: Sun Jun 14, 2015 8:24 pm
by errolflyn
thank you Mike yours too
Re: Slow speedo
Posted: Sun Jun 14, 2015 9:03 pm
by 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 ?
Re: Slow speedo
Posted: Sun Jun 14, 2015 9:19 pm
by errolflyn
I think thats ok and is certainly is moving but not sure if its right
Re: Slow speedo
Posted: Sun Jun 14, 2015 10:19 pm
by 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
Re: Slow speedo
Posted: Mon Jun 15, 2015 6:49 am
by errolflyn
Really where am I going to find one of them
Re: Slow speedo
Posted: Mon Jun 15, 2015 8:31 am
by mike.perry
Try MMOC Club Spares or Nat. Rally
Re: Slow speedo
Posted: Mon Jun 15, 2015 11:48 am
by 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.
Re: Slow speedo
Posted: Mon Jun 15, 2015 11:50 am
by MrIan
Re: Slow speedo
Posted: Mon Jun 15, 2015 8:45 pm
by 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
Re: Slow speedo
Posted: Mon Jun 15, 2015 9:23 pm
by 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!
Re: Slow speedo
Posted: Wed Jun 17, 2015 10:29 pm
by 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
Re: Slow speedo
Posted: Thu Jun 18, 2015 1:31 pm
by 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
Re: Slow speedo
Posted: Fri Jun 19, 2015 12:00 am
by mike.perry
If you have an 803 gearbox and diff then a 1000 TPM speedo will be correct
Re: Slow speedo
Posted: Sun Jun 21, 2015 7:54 pm
by bmcecosse
NOT with that final drive ratio !! You need ~ 800 tpm.
Re: Slow speedo
Posted: Mon Jun 22, 2015 8:37 am
by 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.

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Re: Slow speedo
Posted: Mon Jun 22, 2015 1:16 pm
by 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
Re: Slow speedo
Posted: Mon Jun 22, 2015 1:21 pm
by 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
Re: Slow speedo
Posted: Mon Jun 22, 2015 2:10 pm
by liammonty
Good luck! It should be far closer than your current one.
Re: Slow speedo
Posted: Sat Jun 27, 2015 2:18 pm
by 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