Swapping speedo's

[glokkk]

Hello from Australia. I have a 1958 Minor 1000 with the speedo (silver face?) mounted in the centre of the dashboard. I have obtained a black faced speedo from the later model Minor 1000 that I want to install, but I have been advised that the fuel gauge won't work in my model minor. I don't want to swap the silver fuel gauge into the black face (doesn't look any where near as smart, which is part of the reason for the swap).
Q. Can any one help me with what I need to do to be able use the black face fuel gauge; i.e., what wiring mods are needed?

[IslipMinor]

If you have the standard 948 rear axle ratio of 4.55:1, and standard 948 speedo then the 1098 black faced speedo will over-read in speed and distance as it is set up for the 4.22 axle.

There are some numbers on the face of the speedo above the odometer, it should be be 1504 if it is a 948 speedo and the black one 1408 - is this what you have? If so the error will be about 7% higher than the standard 948 speedo.

The black fuel gauge needs the voltage stabiliser from the later 1098 models as it works off 10v, instead of the full 12v.

[glokkk]

Thankyou Richard. Yes the 948 rear axle will mean the speedo requires re-calibration which I am aware of.
Black faced speedo has the following numbers just below the odometer "SN.4423/05 880"

The black faced speedo has a regulator screwed to the back of the speedo, with "Smiths BR 1308/00" printed on the regulator, and a green wire connected from the regulator to one terminal on the fuel gauge.
I'm more concerned about getting the fuel gauge to work in my 948cc vehicle, if that makes sense. Can you advise on that matter at all?
regards,
Peter

[bmcecosse]

There must be more numbers on the black speedo - as Richard suggests - look for 1408. If it is a Mini speedo then the numbers could be different. Note the 948 speedo will already over read by ~ 5% , so fitting the wrong speedo will make it seriously over-read. 'Recalibrating' is a very expensive business.....Better way will be to fit a 4.22 (or even 3.9) final drive ratio in the axle ! The black fuel gauge uses a different tank sender unit - as well as the 10V supply.

[IslipMinor]

The 880 is the kilometre equivalent of the 1408, so that is what it should be if the dial is in kph?

What does the 948 speedo have?

The other terminal on the voltage stabiliser has a fused ignition switched supply, which could come from the existing supply to the fuel gauge. The second terminal on the gauge itself goes to the tank sender unit. Might be worth connecting it up and seeing what readings you get?

Be very careful when making the connections as if the feed to the tank unit gets flashed with either 10v or 12v it will be fried!

[glokkk]

Thankyou once again; now it seems we are getting somewhere. So I need to use the SENDER UNIT from the same vehicle that the speedo came from; that makes a lot of sense.
On the subject of re-calibrating the black speedo, it is not overly expensive here in the land of Oz, I have had it done before. However with much respect, that is not my issue at all, I am concerned with the ability to make proper use of the entire black face speedo & utilise the black faced fuel gauge as well.
I understand all the issues with final drive ratios, and speedo readouts, etc. and I thankyou for pointing these things out, but more importantly, I need to know how to make use of the black faced fuel gauge. That is the advice I was seeking from the forum.
So to sum up, have I got it right that I need find a way to use the appropriate sender unit??

[bmcecosse]

I think so - but no great harm trying it as it is to see what happens. Seems a strange thing to do - most folks with early cars like to hang on to the early face speedos ! Well spotted Richard on the 880 re KPH.

[mike.perry]

You can use a black speedo from a 1098 LCV, that has a 4.55 diff, the same as the 948 car. You will need to use the voltage stabiliser which should be attached to the speedo for the fuel gauge

[glokkk]

your help and advice is appreciated. My vehicle has been modified, so no real issue about "keeping it original". The 948 engine has been bored to 1030cc, inlet manifold separated, mild cam, duplex timing chain & gears, 12G295 head, lightened flywheel, MG Midget clutch, ribcase gearbox from 1098 Minor, and telescopic shock absorbers fitted along with front stabiliser bar and a slightly larger diameter exhaust system with less restrictive muffler (not loud). The modifications have made a significant improvement to the cars performance and handling.
The black faced speedo has indeed MPH & KPH displayed on the face, however I don't know what vehicle the speedo came from, so I will attempt to attach a photo.

[bmcecosse]

No matter - just try it! With these mods I do suggest a 3.9 final drive would suit nicely - and keep a 1408 tpm (880 tpk) speedo just about dead accurate!

[glokkk]

[frame][/frame]

[mike.perry]

I am compiling a list of speedo options. Could you please tell me the S/N 4423/??
Cancel that, I missed it in a previous post

[glokkk]

By reference to the official wiring diagram for the late model 1098 vehicle, it seems the wire from the tank sender unit connects to one side of the fuel gauge; the other side of the fuel gauge connects to the "I " terminal on the regulator (see photo attached). This leaves the "B" terminal on the regulator which connects to the original power source.
That's my interpretation of the wiring anyhow. Any other thoughts before I make the live connections, & "zap" the gauge into oblivion?
Peter[frame][/frame]

[bmcecosse]

That's correct. I'm pretty sure you need a different sender - but give it a try anyway.....

[glokkk]

Thankyou once again; here goes _ _ _ _

[glokkk]

Did you have any luck with compiling a list of speedo's? The late model 1098cc version of Morris Minors were not sold in Australia, only a handful were ever imported by individuals. As such anything 1098 related is rare or non-existent.
I would be very interested in such a list if you managed to prepare one.
Kind regards,
Peter

[glokkk]

How is that list coming along?

[mike.perry]

There is an early version on the Series MM website, http://seriesmm.mmoc.org.uk Car Ident, Speedometers
I will get a later version uploaded

[Wakko866]

Hi there sorry but it seems this has information I require, currently wanting to swap out a km/h speedo the sn 4423/05 880 I have a replacement mph which has a sn 4423/04 1408, would this work, it's for a 1970 two door saloon,

There was some discussion of changing the rear axle ratio which confused me sligjtly

[Sleeper]

I'll chime in here , I'm not sure if the " continental " speedos are listed in KPH TPK or MPH TPM , but converting mph to kph one multiplies by 1.61 , 880 x x1.61 = 1416 , so maybe you have something there...

John

EDIT reading back over the other posts ( from a few years ago ) it seems the above is correct..