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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Tue Mar 14, 2017 8:56 pm Post subject: Speedo |
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I have just put a 1000 smooth case gear box in behind my 948 motor and in front of a 4.55 diff the speed is so far out I assume the gauge is not right for this setup which gauge should I look for. at 100kmhr the needle is off the clock on zero miles an hour. happy to keep it at miles.
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John Ballard valued contributor
Joined: 11 Feb 2004 Posts: 2646 Location: Dubbo NSW
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Posted: Wed Mar 15, 2017 8:29 am Post subject: |
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The Morris 1000 (948cc) has a 4.55 diff as standard, so the calculation on the speedo should be right
Mine reads 10kph slow but I have a 3.9 diff.
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frosty moderator
Joined: 23 Dec 2003 Posts: 3834 Location: 4559 near a big pineapple, Qld
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Posted: Wed Mar 15, 2017 1:43 pm Post subject: |
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What size tyres and rims are you running Fish ?
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DON58VAN Full Licence
Joined: 25 Sep 2008 Posts: 863 Location: Sydney/Bowral
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Posted: Wed Mar 15, 2017 7:08 pm Post subject: |
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The speedos are calibrated differently for different final drive ratios and models of car (Minis and Oxfords has similar ones).
The calibration--in turns per mile--is shown by a number that is in tiny print on the dial. It will be a number between 1000 and 1500 depending on what speedo you have.
Can you see what calibration number is on your speedo?
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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Sun Mar 19, 2017 6:48 pm Post subject: |
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number on the speedo is 51 114 4 01 09. 1000
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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Sun Mar 19, 2017 6:57 pm Post subject: |
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frosty. tyres I'm running are 175/75 R14.
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DON58VAN Full Licence
Joined: 25 Sep 2008 Posts: 863 Location: Sydney/Bowral
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Posted: Sun Mar 19, 2017 7:51 pm Post subject: |
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The 1000 figure is the one that tells you the TPM.
It is way too low for a 4.55 diff, which explains why it reads way too high.
You need one that is calibrated to around 1400 to 1500 TPM. I will check my reference info and get back to you with the correct TPM or another member may come along and tell us what TPM they have on their standard 948 speedo.
I just realised that you have a '51 model, so you have the little speedo in front of the steering wheel. You will either have to get it recalibrated or there are clever people who have cobbled together little gearboxes that go behind the speedo to make the required correction.
A completely different option is to do as I and a few others have done and ignore the mechanical speedo and use a dedicated GPS speedo instead.
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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Sun Mar 19, 2017 8:12 pm Post subject: |
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No this speedo is in my 55 series 2 I have some spare gauges I'll have a look at what they are.
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DON58VAN Full Licence
Joined: 25 Sep 2008 Posts: 863 Location: Sydney/Bowral
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Posted: Mon Mar 20, 2017 10:29 am Post subject: |
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I confess that I was assuming you had the big central speedo in my earlier posts.
I assume that a 55 model would have the one in front of the steering wheel. If that is the case, I doubt you will get one that has the right calibration.
There is much more choice of TPM with the big central one.
So I am sorry if I have confused matters.
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John Ballard valued contributor
Joined: 11 Feb 2004 Posts: 2646 Location: Dubbo NSW
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Posted: Mon Mar 20, 2017 12:56 pm Post subject: |
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Tyres will be going along way to putting the speedo out.
Correct tyres for a Morris is 155/80/14 a bit hard to get but they do fit a 3 inch wide wheel
!75.75/14 are nearly 18mm higher and need to go on a 5 inch wheel.
A much better choice is 165/775/14 which fit a 4 inch wheel ( perfect with Major wheels) and only 5mm higher/.
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DON58VAN Full Licence
Joined: 25 Sep 2008 Posts: 863 Location: Sydney/Bowral
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Posted: Mon Mar 20, 2017 1:02 pm Post subject: |
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John
Unless I am very much mistaken, larger rolling radius tyres will make the speedo read lower, not higher than actual speed.
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frosty moderator
Joined: 23 Dec 2003 Posts: 3834 Location: 4559 near a big pineapple, Qld
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Posted: Mon Mar 20, 2017 1:48 pm Post subject: |
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1955 should have a centre dash speedo not like earlier in front of steering wheel.
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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Mon Mar 20, 2017 4:06 pm Post subject: |
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[quote="DON58VAN"]I confess that I was assuming you had the big central speedo in my earlier posts.]
Hi Don58van
got the dial in the middle of the car gold face.
the other 2 gages are gold one has 1500on it and the other 1504
what should I go to get it close knowing the wheels will put it out as well.
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DON58VAN Full Licence
Joined: 25 Sep 2008 Posts: 863 Location: Sydney/Bowral
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Posted: Mon Mar 20, 2017 4:56 pm Post subject: |
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Quote: | got the dial in the middle of the car gold face. |
In that case it is almost certainly from an Oxford. Wouldn't your car be a '56 if it had an 803cc and a central speedo?
Quote: | he other 2 gages are gold one has 1500 on it and the other 1504 |
Have you tested them to see if they work? You can use an electric drill running in reverse. You will need to cobble together a square section drive from the drill to the speedo.
There is no significant difference between 1500 and 1504, so you can try either one.
It is a bit of suck-and-see with the speedo. With your tyres and one of your spare speedos it may read a bit too low.
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John Ballard valued contributor
Joined: 11 Feb 2004 Posts: 2646 Location: Dubbo NSW
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Posted: Mon Mar 20, 2017 5:04 pm Post subject: |
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I had a speedo recalibrated a few years ago, and about to get another done as my black face speedo I bought of e-bay (with klms/per hr) is about 10 klms fast at 60.klm/hr
I use Manly Instruments in Manly Sydney what they ask you to do is tell them how many turns the speedo cable turns in 20 meters.
Here is what I do to get that.
1. Put two sticks in the ground exactly 20 meters apart
2. Undo the speedo cable and bring the end down from behind and in sight.
3 Mark the cable with a pen ( mine has a square end)
4. Park the car with the front wheel axle aligned with the first stick.
5. Drive to the next stick and count the turns including 1/2 or 1/4 turns.
Easier with a helper and you can push the car the last meter or so.
The white face one I had done before was accurate but then I changed the gearbox and diff.
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Scouse moderator
Joined: 15 Sep 2003 Posts: 5266 Location: Wollondilly, NSW
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Posted: Mon Mar 20, 2017 5:28 pm Post subject: |
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DON58VAN wrote: | Wouldn't your car be a '56 if it had an 803cc and a central speedo? | Series II with the centre speedo was released in late '54. The 1000 came about in late '56.
99% of late SIIs here are '55/'56.
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Scouse moderator
Joined: 15 Sep 2003 Posts: 5266 Location: Wollondilly, NSW
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Posted: Mon Mar 20, 2017 5:31 pm Post subject: |
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There's a lot of speedo info here:
http://potteries.mmoc.org.uk/ID/Speedo.htm
'1500' is from a 1000 sedan,
'1504' is from a 1000 traveller.
I'm not sure why the TPM varies though but it's only miniscule.
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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Mon Mar 20, 2017 6:57 pm Post subject: |
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DON58VAN wrote: | Quote: | got the dial in the middle of the car gold face. |
In that case it is almost certainly from an Oxford. Wouldn't your car be a '56 if it had an 803cc and a central speedo?
Yes it had a 803cc an yes we worked it out to be a late 55 early 56
Quote: | he other 2 gages are gold one has 1500 on it and the other 1504 |
Have you tested them to see if they work? You can use an electric drill running in reverse. You will need to cobble together a square section drive from the drill to the speedo.
There is no significant difference between 1500 and 1504, so you can try either one.
It is a bit of suck-and-see with the speedo. With your tyres and one of your spare speedos it may read a bit too low. |
tested the 1500 yes it seems to work ill give it a try next week got a run this Sunday to willow tree, GPS will have to do.
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Fishmm51 overdrive
Joined: 28 Jul 2015 Posts: 92 Location: NSW Upper Hunter
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Posted: Mon Mar 20, 2017 7:04 pm Post subject: |
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Cheers guys for everyone's help.
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frosty moderator
Joined: 23 Dec 2003 Posts: 3834 Location: 4559 near a big pineapple, Qld
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