57 replies to this topic

[ckneller321]

Hi
Just bought a smiths electrical speedo so i need to get a speedo pulse generator to convert it from mechanical. Does anyone know where i can get one from that will fit the minis speedo cable?

Chris

[dklawson]

This subject comes up periodically so you may want to search for old threads for electrical and/or electronic speedometers. Perhaps someone posted a source in those threads.

I remember that various Jags from the mid- to late-1980s used an electronic speedometer. If you find one in a breakers yard you should be able to fit its sender to the Mini without difficulty. Over here at least, the common speedo pulse generators have 5/8-11 threads. That's nowhere close to what you need for the Mini as it uses M19x1 threads on the cable connection point.

[ckneller321]

so there is, sorry! muchly appreciated!

[dklawson]

I did a little Googling on this today.

FYI, I "think" you'd be OK using the following item found on '82-'87 XJ6 and '82-'84 XJS Jaguars.
Part #DAC4570
Available new at:
http://www.britishpa.....ER TRANSDUCER
Picture at:
http://www.importpar...rge/item/235668

This is a 2-wire sensor. Make sure your new speedo can accept a 2-wire sensors before you go looking for one of these. I know you can set VDO and AutoMeter speedometers to work with 2-wire sensors. There are other Jag sensors available but some specifically talk about needing a signal amplifier to work. I don't believe DAC4570 does. However, it would be wise to call a local Jag repair shop and confirm this before buying either a new or used sending unit.

EDIT:
You should also visit the Caerbont web site (modern day Smiths) and contact them about what sensors are compatible. I was looking at their tech pages:
http://www.caigauge....nstructions.htm
also see their page on hooking up different sensor types:
http://www.caigauge.com/speedofit.htm
The Jag sending units may behave like their magnetic pickups but I'm not sure. A telephone call to Caerbont should help sort this out. In my experience they are either slow (or fail to) respond to emails.

Edited by dklawson, 23 July 2007 - 02:46 PM.

[ckneller321]

right im not sure on that, might need some help! its one of the telemetrix range ones if that helps. the info i got with it says i have wires for connecting to...........

switched ignition +ive 12V supply, 3A fuse

connected to harness reset switch OR not used

pull up/down (if required)

instrument illumination, 12V supply sidelight feed

earth

speed signal input (hall ECU)

speed signal input for low voltage output senders


so im not too sure on a lot of these except the obvious 3 of power, earth and illumination

[redhotmini]

iirc the telemetrix gauges are made by caerbont, so it would be worth giving them a call

[dklawson]

I agree. Give Caerbont a call and discuss with them what you've bought and the potential sending unit I'm suggesting. They may have some alternates they can suggest that are better options.

Getting Caerbont involved insures that you'll end up with a compatible sender and gauge. You'll be happier in the end once you call them.

[ckneller321]

right well ive been talking to the company i bought them off and their technical advisor says there shouldnt be a sender that doesnt work with this speedo soooooooo hopefully!

[dklawson]

Well, I think the biggest problem will remain finding a sender that will screw directly onto the Mini gearbox. The Jag senders I mentioned earlier should work if the seller assures you that virtually any sender will work.

My advice would be to find a sender, any sender, and set up the gauge on the bench with a 12V power supply. Operate the sender with an electric drill to make sure you can get the speedo and odo to work. You might have to try multiple switch settings to get a combination that works.

by the way, unlike mechanical speedos, electrical/electronic ones don't care which way the sender is rotated. CW or CCW... it will count the same if it counts at all.

[v8mini]

on my VDO speedo i've got a Hunter transducer that fits on the end of the speedo drive using the orgional conector.

http://www.sailesmar...p?Q=transducers

not sure which one fits, i will see if i can see a part number on mine later

[dklawson]

That's an excellent link.

Take a look at the following two senders:
71H &
FX4H

IF you want to leave the cable in place at the gearbox end, the 71H sender has both male and female M12x1 threads. This will screw onto the speedo end of an early type speedo cable (center binnacle type).

The FX4H sender has a 3/4-25 nut on it. That isn't exactly M19x1 but it's so darn close I'm sure it would fit the Mini gearbox. The only concern I have is the shape of the drive key on that sender is shown as rectangular. However, a few moments with a file and I'm sure it could be changed to the 0.120" square key used on the Mini gearbox. OR... the vendor could probably supply it with a square key like is used on the 71H sender. The keys are typically a separate part and I'm sure you can move them from sender to sender. It wouldn't be economical for them to make them any other way.

Please let us know which model you used. For my personal reference... please let me know how much (roughly) they cost.

[ckneller321]

ok so on the 71H one which supply voltage and pulses options would i need?
and this one can be fitted onto the gearbox cant it? not just on the end of the old style speedo cable?

Edited by ckneller321, 20 August 2007 - 05:24 PM.

[dklawson]

No, as I mentioned in my last post the 71H would fit on the SPEEDO END of the center binnacle speedo cable (M12x1 threads). The Mini gearbox has a male M19x1 male connector. The FX4H sender in the link has a 3/4-25 female nut on it. THAT is what you'll need if you want a sending unit mounted on the gearbox. The FX4H SHOULD fit the Mini without problems. The difference is... 3/4" is 0.002" bigger than 19mm and the 1mm pitch is different by .0006" per turn... so it will probably fit just fine.

As far as what type the sender is... you'll need to contact the folks in the link above. There are 2-wire and three-wire senders. I know the VDO speedos can accept either, I believe the Caerbonts will also. Once you have the sender it will be a simple task to set this up on the workbench using an electric drill and changing switch settings until you get a working combination.

Edited by dklawson, 20 August 2007 - 07:54 PM.

[dklawson]

V8Mini, please post which transducer you selected. You said that it went on the end of the speedo drive... do you mean the cable end or the gearbox end?

I contacted Sailes to ask about their sensors. They are 3-wire Hall Effect sensors. That means you'll need to connect the blue (earth) and brown (power) wires from the transducer to the Smiths/Caerbont gauge. The third wire is the pulse input to the speedo and you'll need to connect it to the proper point on the gauge and set the gauge's switches accordingly.

I asked Sailes about which model they recommend for a Mini and I did not agree with what they said. They recommended the 69H transducer which has 22mm threads. That's not right. Perhaps he thought I meant "MINI" as in BMW. His other recommendation was for one that screws onto the end of the speedo cable (i.e. like the 71H I mentioned earlier). He also recommended another "end of cable" transducer that probably fits the later Minis with the clip-on speedo cable.

I still think the FX4H would fit best ... IF it can be ordered with a square drive key. The pitch of the threads is off a tiny bit but I believe it should screw directly onto the plastic boss of the Mini's gearbox.

Again, V8Mini, please post which sending unit you purchased.

[ckneller321]

Which one was suggested for the end of the later type speedo cable?
And do you think this would be as good a solution as the others?