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speedo error
https://www.ausmini.com/forums/viewtopic.php?f=2&t=88298
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Author:  1970cooper [ Thu Jan 15, 2015 5:37 am ]
Post subject:  speedo error

I finally got my 1978 1275 LS on club plates.

Problem is that my speedo is over reading by 10 K's consistantly at all speeds.
Do you guys think it's the speedo or the drive gear in gear box housing at the end of the speedo cable.

Any advise will be appreciated

Author:  drmini in aust [ Thu Jan 15, 2015 6:50 am ]
Post subject:  Re: speedo error

All Oz Minis had the same drive gears in the gearbox, unlike Rovers in UK.
We changed the speedo head for different diff ratios.
So, more likely it's the speedo head.
Does it measure distance correctly? If so it's the right speedo head, just get it calibrated. Or, fit a GPS like I did. :)

Author:  peterb [ Thu Jan 15, 2015 7:43 am ]
Post subject:  Re: speedo error

Sometimes if the speedo head 'mechanism' is a bit gunked upit can cause them to read high. It gets in around magnet/disc area. I clean them with contact cleaner spray then light spray of good brand WD type spray.

Author:  phillb [ Thu Jan 15, 2015 7:49 am ]
Post subject:  Re: speedo error

This will probably be frowned upon as being bodgy but mine was consistently hi. I figure over years the very fine spring that the holds the needle to zero weakens.

See if you can open the speedo to access the needle and are able to have it free from the zero rest pin.

Note where the needle rests when not touching the rest pin.

Gently push/rotate the needle anticlockwise by gradually increasing amounts, each time check to see if the natural rest point has moved to a poition equivalent to say 5-10kph. It might take some trial and error.

I did this with my large early style speedo and now its quite accurate. I don't know how this might work with a Leyland style speedo and as I say probably a bit bodgy so try this at your own risk.

Author:  drmini in aust [ Thu Jan 15, 2015 8:01 am ]
Post subject:  Re: speedo error

I have a recent 200KMH Smiths (so called) speedo in mine. It is for a 3.444 diff, but I'm currently running a 3.647. So, it should read fast.. right?
Well.. it did, at first. Now, after 20K Km, it's consistently reading 10KMH slow. But the distance is still reading high, go figure. :roll:
Needle is steady, so.. I dunno.
So, I'm about to replace it with a real Smiths 140KMH one [800 turns/km], out of a Moke. 8)

Author:  9YaTaH [ Thu Jan 15, 2015 8:10 am ]
Post subject:  Re: speedo error

peterb wrote:
Sometimes if the speedo head 'mechanism' is a bit gunked upit can cause them to read high. It gets in around magnet/disc area. I clean them with contact cleaner spray then light spray of good brand WD type spray.


Nooooooooooooooooooooooo :!: :shock: :lol:

Kitchen table (away from all the magnetic swarf in your garage), a hand made tool made from a hack saw blade and you VERY carefully coax the iron fillings off the magnet and drag cup assembly and anywhere else you see em.

If partially disassembled, you can then carefully clean out old gunk on the drive gear and odometer cam with contact cleaner (say) then sparingly coat with Moly Grease (do not over grease).

Do not overgrease the speed cable, especially up near the head...

[EDIT: I drew a tool :lol: ]

Image

Author:  9YaTaH [ Thu Jan 15, 2015 8:12 am ]
Post subject:  Re: speedo error

1970cooper wrote:
I finally got my 1978 1275 LS on club plates.

Problem is that my speedo is over reading by 10 K's consistantly at all speeds.
Do you guys think it's the speedo or the drive gear in gear box housing at the end of the speedo cable.

Any advise will be appreciated


It reads consistently :?: Leave it :!: Don't touch a thing :!: :lol:

Author:  9YaTaH [ Thu Jan 15, 2015 8:14 am ]
Post subject:  Re: speedo error

phillb wrote:
This will probably be frowned upon as being bodgy but mine was consistently hi. I figure over years the very fine spring that the holds the needle to zero weakens.

See if you can open the speedo to access the needle and are able to have it free from the zero rest pin.

Note where the needle rests when not touching the rest pin.

Gently push/rotate the needle anticlockwise by gradually increasing amounts, each time check to see if the natural rest point has moved to a poition equivalent to say 5-10kph. It might take some trial and error.

I did this with my large early style speedo and now its quite accurate. I don't know how this might work with a Leyland style speedo and as I say probably a bit bodgy so try this at your own risk.


No problem with that, so long as you are super gentle clamping (pointy flat nosed pliers) the spindle to turn the pointer :arrow: (except that in some speedos you may reach a point where you run out of spring tension and the pointer will no longer return to rest...moving the pointer to a new position may also effect the linearity...so when you are happy at say 100Km/Hr, might be a good idea to check accuracy at some other speeds...)

Author:  phillb [ Thu Jan 15, 2015 8:44 am ]
Post subject:  Re: speedo error

9YaTaH wrote:
phillb wrote:
This will probably be frowned upon as being bodgy but mine was consistently hi. I figure over years the very fine spring that the holds the needle to zero weakens.

See if you can open the speedo to access the needle and are able to have it free from the zero rest pin.

Note where the needle rests when not touching the rest pin.

Gently push/rotate the needle anticlockwise by gradually increasing amounts, each time check to see if the natural rest point has moved to a poition equivalent to say 5-10kph. It might take some trial and error.

I did this with my large early style speedo and now its quite accurate. I don't know how this might work with a Leyland style speedo and as I say probably a bit bodgy so try this at your own risk.


No problem with that, so long as you are super gentle clamping (pointy flat nosed pliers) the spindle to turn the pointer :arrow:


Actually that's not what i meant but that would work. (Probably better). Ie you were able to reposition the needle on the spindle 10kmh less.

I couldn't budge my needle loose from the spindle, so I just wound the needle backward against the spring, effectively tightening the spring and therefore decreasing the speed.

If it's consistantly out then repositioning the needle on the spindle would be the ideal solution.

Author:  9YaTaH [ Thu Jan 15, 2015 8:58 am ]
Post subject:  Re: speedo error

The needles are just a simple interference fit on the end of the spindle...but...if one has been on and off too many times and becomes loose...someone (who will remain nameless) may have glued it back on)

When carefully turning the needle a small amount or pulling the needle off, you should "clamp" the spindle to avoid damage to locating jewels, whatever

Author:  Timbo [ Thu Jan 15, 2015 10:22 am ]
Post subject:  Re: speedo error

9YaTaH wrote:
The needles are just a simple interference fit on the end of the spindle...


I'm not sure that this is always the case. There are at least two major styles of speedo. The early 850s and the late Mokes used UK built speedos, which have a different mechanism. Their needles seem to be much more strongly attached than in the Australian built speedos which were used in the 'in-between' years.

Tim

Author:  drjbeam [ Thu Jan 15, 2015 10:30 am ]
Post subject:  Re: speedo error

Im on me second speedo had the same prob with the first on that come with the car

Its a 74 model even changed the cable at the same time when i changed speedo same problem as the first one i just use a gps still like i did with the first speedo

Author:  9YaTaH [ Thu Jan 15, 2015 11:52 am ]
Post subject:  Re: speedo error

Timbo wrote:
9YaTaH wrote:
The needles are just a simple interference fit on the end of the spindle...


I'm not sure that this is always the case. There are at least two major styles of speedo. The early 850s and the late Mokes used UK built speedos, which have a different mechanism. Their needles seem to be much more strongly attached than in the Australian built speedos which were used in the 'in-between' years.

Tim


Sure...my advice was fairly general motors in nature :D

Author:  peterb [ Thu Jan 15, 2015 12:28 pm ]
Post subject:  Re: speedo error

Don't worry about fixing it, the cop will tell you how fast you were going.

Author:  jubblies [ Thu Jan 15, 2015 12:34 pm ]
Post subject:  Re: speedo error

Is this a typical 1275ls thing?
I remember driving one a long time ago and the speedo was incorrect (unsure if it read over or under). The story I was told is it will be incorrect as it's the same equipment as a std mini but with 12" wheels fitted.
Not sure about the story as I'm sure to meet ADRs it would have to be correct at the time it left the factory.deanna.
Is it different gearing on the speedo or the gearbox? If it's in the speedo could it have been swapped with an earlier 10" wheel speedo?
Just a thought?!

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