Best solution for a non-voltage stabilized mk1

[mikepal]

Hey all,

I tried searching but just got more confused. I have a 63 Morris Cooper that had been “restored” they seemed to have replaced some parts but not all. The result is that I have a mix between voltage stabilized parts and non-stabilized parts. My plan is to replace the temp gauge, temp sender, fuel sender and fuel gauge while adding a voltage stabilizer to bring the car up to the point where parts are still supported.

Is this the right direction to proceed in? Will I be opening a can of worms in relation to wiring? I’d also be open to more intelligent solutions that may save me money and time.

From what I have gathered…I have a failing non-voltage regulated fuel sender connected to a non-voltage regulated fuel gauge. A voltage regulated temp sender hooked up to a non-voltage regulated gauge. Fuel gauge is starting to fail and my temp gauge will always move to hot even if the motor is at normal operating temps.

Any help will be appreciated!

[Polarsilver]

Been there & done that.. you can find company that will repair an original Smiths voltage stabilizer also the like of Minispares sell their version ..but when i needed MS were out of stock.. my Solution was to get from ebay a electronic voltage stabilizer for about £12 ..these sorted out my issues on the last two cars .. the ones i buy do have very short supply cables so not that easy to hide them out of sight without increasing the cable length .. Note they are only for Negative Earth .. but it is possible to get positive earth versions.
I also purchased a Minispares Fuel Gauge & that worked all ok with the ebay voltage stabilizer.

Just saying it could well be something other such as polarity mix up with none stabilized gauges .. my solution drop the heater down to get access to the Pod Screws & take out the Gauge Pod & get all the gauges working on slave wireing out of the car .. sod of a job to fight the heater & dash trim but i found this method worked for me.

Remember to tell us what the final fix was to help others.

[AndyPen]

I'd be tempted to find the right sender myself, they do come up. Also, how do you know that it is the gauge that is failing? Could it be the sender or as often happens, simply a connection gone dry?

[timmy201]

What kind of fuel tank sender do you have - bolt on or locking ring? If you have a non-stabilised fuel sender then chances are it’ll be a bolt on type which I believe isn’t available in a stabilised version

If you don’t want to swap the tank and the sender is working, you might be able to use the “Spyder fuel gauge wizard” to link the signal from one type to the other

[mikepal]

I searched high and low for a non-voltage stabilized fuel and temp sender for sale. I thought I had tracked down a temp sender in Australia but it was already sold.

My fuel sender is a lock ring style. When I replaced the sender my gauge reads backwards (full being displayed as empty). The tech advisors at Mini Spares lead me to believe that there is an incompatibility with the new sender and the old gauge.

Same is true with the temp sender. It’s a new replacement part that was designed to work with a stabilized temp gauge. I am assuming that my faulty readings on the gauge is because the sender doesn’t match the gauge.

If anyone knows of a non-voltage stabilized fuel sender and temp sender I’d be thrilled to go that direction. As mentioned my solution is to make it easier to repair should one of those senders fail again in the future.

[1071 S]

Its been a while but I’m sure I didn’t jump through many hoops when I did mine.

My old (bolt in sensor) type tank developed a few pinholes so I just replaced it with a newer (bayonet fitting) type tank (with the later sensor).

Obviously the gauge no longer worked but it was only a case of finding a later gauge ..and voltage stabiliser. The new gauge bolts straight into the original (120 mph S type) speedo and the new gauge is then wired in using the 10V output from the stabiliser ..instead of the earlier 12V input.

My (hazy) memory is that the old and new gauges operate in opposite directions...... so its just a case of swapping the input and output over. A quick review of the relevant wiring diagrams (RTFM;) will set you right.

You don’t need any special bits apart from a stabiliser and gauge from any centre speedo Mini.

Cheers, Ian

[timmy201]

If you already have a tank with the locking ring, then I’d swap the whole thing onto the stabilised setup. It’s much easier to get the parts, especially compared to the non-stabilised locking ring sender

[1071 S]

Just as I described above.... And checking my wiring diagrams it would seem the the older type gauge takes a straight 12V in (from one of the fuses) (terminal may be marked "B") and is regulated by a controlled earth out through the sender. The newer gauge (from 64 is fed a regulated voltage through the stabiliser (10V I seem to remember from somewhere) and also earths through the sender.

My previous post may be in error in that in teh wiring diagrams the left hand (as you look at the diagram) terminal connects to the sender.

The later temp gauge also uses a stabilised supply but I just left my original connected to 12V.

Cheers, Ian

[CooperTune]

Thanks I think. I'm trying to wrap up a 64 998 Morris Cooper. One of the last issues is a non working fuel gauge. I have over the years replaced lots of later senders. They have all been bayonet style mount. This car has a fuel tank with bayonet style mount but the sender appears to be made like a bolt in sender with connections bolted rather than blade. Is this something else I have never seen or a dodge repair? Looking at rear of speedo there is no voltage stabilizer. This car has been all but unusable for years due to poor on poorer repairs. It appears I need a later speedo. Or an earlier tank and new bolt in sender from Mini Spares. Steve (CTR)

[Simon776]

From roughly mid February to October 1964 BMC used a hybrid fuel sender on Mini saloons which had the ring type fixing but was for the 12 volt non-stabilised fuel gauge.

[Peter Laidler]

I say that Simon is right and that there was a changeover period between BMVIS and (Bi metal voltage instrument stabilised) and NON BMVIS tank sender units.

To be honest Mike, the two BMVIS and NON BMVIS systems are NOT compatible and never the twain should meet. I suggest that you opt for one system or the other I'm sure that BMVIS instruments and tank unit plus reliable electronic instrument stabilisers in both + and - format are available. But Mix and match (or pick and mix) there is a recipe for confusion, head scratching and faulty instruments from the word go.

That's just how I see it.

[AndyPen]

From roughly mid February to October 1964 BMC used a hybrid fuel sender on Mini saloons which had the ring type fixing but was for the 12 volt non-stabilised fuel gauge.

Interesting, my Feb 64 tank was a screw in and I didn't realise it changed so soon after

[1071 S]

I find it difficult to understand why people find it so hard to understand the point Peter raise above. The Factory workshop manuals have pre-64 wiring diagrams (annotated as "up to 64" - Page N-4) and then "64-67 Page N-8".

Obviously, (based on the diagrams) sometime in 64, they changed the sender AND the gauge..... You can identify which sender you have by its mounting method (multiple small screws vs locking ring). Identifying the gauge is a little more subtle - but equally obvious. When you turn on the ignition, the needle on the early gauge immediately flicks to the appropriate reading (sort of flicks a bit with no/dead sender). The needle on the later gauge moves more deliberately into position.

The stabiliser is just an integral part of the new system.

If you need a replacement old sensor - but can't find one - the only obvious (and quite simple solution) is to swap both sender and gauge (and tank;) not forgetting to install the stabiliser.

It's been a long time.... but I have feeling that repairing the old sender may not be such a big deal..it's a pretty simple rheostat ...would calibration an issue???

Cheers, Ian

[CooperTune]

As it turns out the 7/64 Morris 998 Cooper and my 64 1071 Austin Cooper both have the same twist loc tank with the pre stabilized sender. To be honest while I can sort out electrical issues it is not something I enjoy. While clearly not correct I have a couple of early bolt in sender tanks. If MSC has correct bolt in sender, and the sender ends up being my issue problem solved. I also wonder if with the original sender and a new bolt in, if a new working transition sender can be built? Steve (CTR)

[Peter Laidler]

Re your comment above Steve. Thinking on my feet with no experience and never having done it........ Regardless of what sort of tank you have, screw-in or bayonet, if I needed a BIMVS type sender to go in my bolt-in tank I'd set about making a new plate (from brass and easy to soft solder) and attach the internal BMVIS sender guts to it. Soft solder in place, seal and that's it. Indistinguishable on the outside - an original bolt-in tank with readily available BMVIS type guts.

Or have I lost the plot somewhere along the road?

[CooperTune]

This subject sure dropped in a hurry. I have been working my punch list as the 998 wraps up. The best I can tell the gauge is my problem. Before removing the speedo I'll attach the replacement and ground it and see if it works. Having put 9 volt battery across it reads 3/4 tank? Steve (CTR)

[Peter Laidler]

As a general rule in our big calibration bay, gauges that work, even barely or to some extent indicated to us that was a READING fault or an external fault As such the reading could be re-calibrated on the bench. The little gauges, such as the CAV's, Lucas and Smiths found on small trucks, Land-Rovers etc etc the gauge indicator or pointer or needle, had what we called 'jumped the tracks' at its balance or axis point.

[mikepal]

I wanted to provide an update. I successfully added a voltage stabilizer, replaced the temp gauge and fuel gage. Thanks to the wiring diagram in the shop manual it was an easy and straight forward process. All of my gauges now read correctly.

I haven’t been able to drive the car on a hot day so I can’t tell if my solution fixed all of my concerns with the inaccurate temperature reading. I do know that I have an accurate reading on my fuel level. Progress!

Thanks to everyone for all of your help!

[AndyPen]

From roughly mid February to October 1964 BMC used a hybrid fuel sender on Mini saloons which had the ring type fixing but was for the 12 volt non-stabilised fuel gauge.

Yes indeed, and my mid Feb 64 has the screw in type, so must have been one of the last ones.

[65MK1S]

They now make DC to DC converters that take 6 to 18v DC and
convert it to a fixed 12v DC if that helps anyone.