Voltage stabiliser/temperature gauge problem

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Owlsman
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Voltage stabiliser/temperature gauge problem

Post by Owlsman »

Let me apologise, to start with, for what to many of you good people will appear like a dumb query but here goes anyway...….I've had a brand new Smiths electrical temperature gauge 'professionally' fitted to my '62 Minor 1000 which works but, to my thinking at least, constantly reads very high.

It reads alarmingly high (140 degrees C) shortly after setting off i.e. when fully warmed up, before settling back to around 110/120. I've read several threads on here about how a temp gauge should be wired up via the voltage stabiliser. On checking how mine was wired by the garage, it is via 'A4' on the fuse box which (apparently but don't ask me how, accounts for the erratic and high readings) so I decided to try and 're-route' it by connecting to the voltage stabiliser……..but I don't appear to have one!!

I've removed (i.e. pulled out) the speedo but there's nothing resembling a voltage stabiliser on the back of it. Of the 3 green wires fitted to one side the petrol gauge, 2 disappear into the main wiring loom and the third one does likewise eventually I think, but is connected to the oil pressure warning light switch first - actually by a double bullet connector.....but I'm guessing that may be an 'after-market' extra!

From the wiring diagram of my recently purchased workshop manual, I was unsure whether my car was the 'early' or the 'later' version but I'm now fairly convinced it is the early type as only the later one has a voltage stabiliser shown and also the early wiring diagram shows wiring for 2 horns, which mine has.....although only 1 horn is fitted. (I've actually just purchased a second horn as I don't like the idea of and don't like to see 2 wires flapping about not doing very much!!)

I suppose what I really want to know is whether my car will have a voltage stabiliser but somewhere other than attached to the speedo or if not, if it's possible to 'retro fit' a voltage stabiliser just for the temperature gauge and if so, how? Can I use the existing wire that already powers the gauge? Is it likely that my gauge will show more normal/less volatile readings with a V S?

Perhaps I should add that 1) There is no evidence whatsoever that the engine is overheating …..but with the gauge showing 140 at times, I wouldn't be any the wiser if it was! 2) The car is fitted with a dynamo and I have no plans, in the foreseeable, to change that. 3) The fuel gauge works just as it should.

Many thanks, in advance, for any help and advice you can give me.
Chipper
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Re: Voltage stabiliser/temperature gauge problem

Post by Chipper »

Certainly not a dumb query - not many folk are even aware of the Voltage Stabiliser, hidden away as it is!

Your gauge will read too high, since it is being directly driven by the 14 volts or so that the battery produces with the engine running (i.e., being charged by a dynamo or alternator); the gauge needs a stabilized/regulated feed of 10 volts, which is normally obtained from a bi-metallic strip type unit fitted to the back of the speedo (in post 1962 1098cc Minors, at least).

These provide a 'pulsed' power source, but since the gauge is very heavily damped, the needle appears to be showing a steady reading.

You are probably better off making an electronic version, which should give a more consistent 10 volt feed to your gauge, as per this link:

http://www.britishv8.org/articles/mgb-v ... ilizer.htm
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twincamman
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Re: Voltage stabiliser/temperature gauge problem

Post by twincamman »

Or you can get one specifically for Smiths gauges:-
https://www.europaspares.com/interior-p ... liser.html
Owlsman
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Re: Voltage stabiliser/temperature gauge problem

Post by Owlsman »

Thanks very much for the prompt and helpful replies. My initial thought from 'twincamman' was that it might be a bit beyond me to build my own V S so I am relieved to know that I can buy a ready made jobbie. The link, however, gave me a bit more info about what a VS is and does......but don't ask me to give a lecture on it, just yet!

I presume a purpose built V S would come with some wiring instructions but off the top, will I be able to use the feed that is already connected to A4 of the fuse box?

What still puzzles me is if my car is not fitted with a 'normal' V S, where does the fuel gauge get it regulated 10v feed from?

Thanks,
Alan
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Re: Voltage stabiliser/temperature gauge problem

Post by IslipMinor »

Alan,

The 'hot wire' voltage stabilised fuel gauge was not fitted until ~1964, at the same time as the black faced speedometer. All the gold faced speedos did not use a stabiliser.
Richard


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mobylette
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Re: Voltage stabiliser/temperature gauge problem

Post by mobylette »

I have recently fitted a temp gauge and voltage stabiliser to my 1961 Minor. It will be easy. You can use your existing feed and connect to the 12V "In" tag of the stabiliser, make sure the stabiliser is earthed and connect the 10V "Out" tag to the temp gauge. Job done. If you are handy with a soldering iron you can use one of these:

https://www.ebay.co.uk/itm/TEXAS-INSTRU ... 2749.l2649

Small enough to strap to the back of the temp gauge.(What I did)

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pgp001
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Re: Voltage stabiliser/temperature gauge problem

Post by pgp001 »

I fitted a new voltage stabiliser when I added a temp gauge, I could have used the existing one on the speedo but decided to fit a dedicated supply using one of these.

https://www.ebay.co.uk/itm/Semiconducto ... :rk:4:pf:0

Phil
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Re: Voltage stabiliser/temperature gauge problem

Post by JOWETTJAVELIN »

Forget engine thermometers, spend your time and money on getting the cooling system tip-top, the engine will let you know if its overheating.

Like oil pressure gauges thermometers only add something else to worry about, an ammeter is the only extra instrument worth fitting.
Owlsman
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Re: Voltage stabiliser/temperature gauge problem

Post by Owlsman »

Thanks for all your help and advice good folks.

As I'm not great with a soldering iron I've gone for Phil's suggestion and ordered that semiconductor gizmo from Fleabay. Just as well I read the 'small print' at the bottom of the page, as the one advertised is for a negative earth and my Moggy is positive! The guy has sorted me out however and will put me 'positive' one in the post tomorrow. A very helpful vendor. Hope the VS is as good as his service.

It's always interesting to read about people's views on gauges and instruments. For just about everyone who thinks this or that is essential equipment there's someone who thinks it is a complete waste of time and more trouble than it's worth. There's no right or wrong answer, I suppose...so long as you feel comfortable with whatever you decide to do.

For the record, when I've (hopefully) sorted out the temp gauge I do intend to fit an ammeter......and even a voltmeter. I Know, I know!!

I will give you an update when I've got everything working well.

Many thanks again to yaw'l.

Alan
PS: Can anyone just solve the riddle please about how the petrol gauge works so well on pre-64 models without, seemingly, having a separate voltage stabiliser.
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Re: Voltage stabiliser/temperature gauge problem

Post by pgp001 »

Owlsman

You are right about everyone having an opinion about which if any additional gauges to fit.

On my Traveller I have added Water Temp, Oil Pressure, Volts & Vacuum gauges, I went for a voltmeter instead of an ammeter due to the fact it has an alternator fitted.
Also a cig lighter socket that can power my Sat Nav via a USB port on a digital volts/temp gauge plug in accessory when needed.

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Phil
Owlsman
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Re: Voltage stabiliser/temperature gauge problem

Post by Owlsman »

As I think I posted on my first ever thread a couple of months ago when I first joined the forum, I sort of work on the principle that you can't have too much info on what is happening under the bonnet of, typically, 50/60 year old technology.

I also acknowledge the viewpoint that what you don't know about, you can't worry about. :-?

Personally, I'm not a fan of fitting too much 'modern/hi-tech' stuff to classics. I've had MGBs over the years and never considered fitting power steering, electric windows, adjustable spax shockers etc, etc. If I'd have really wanted such creature comforts I'd have bought an MX 5 in the first place! That is just my viewpoint, however, and I wouldn't ever criticise anyone's decision to do whatever they want to their own vehicles.
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mobylette
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Re: Voltage stabiliser/temperature gauge problem

Post by mobylette »

This article should answer your question re stabilised and non stabilised gauge operation:

https://www.uniquecarsandparts.com.au/h ... fuel_gauge

Basically the later cheaper bi metallic gauges need stabilised voltage, the earlier more complex and expensive magnetic gauges don't.
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Owlsman
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Re: Voltage stabiliser/temperature gauge problem

Post by Owlsman »

Thanks very much indeed for that link...…..I was able to sleep last night, after one less puzzle to rattle round in my head! Unfortunately though, my interior light has stopped working now and I've no idea why but in the great scheme of things, it's more annoying than important, eh?

Thanks again.
Owlsman
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Re: Voltage stabiliser/temperature gauge problem

Post by Owlsman »

Can I just wrap this one please by letting you know that I fitted the gizmo as recommended by Phil and hey presto, the temp gauge reads 'normal' now.....or at least, it never got above halfway on the gauge (90 degrees) on a decent run out this afternoon.

The service, help and fitting instructions, by the way, from this eBay vendor were first class. Highly recommended.

Thank you to everyone who contributed to this thread. I'm much wiser now.

Alan

PS: I sorted the interior light. After removing the open glove boxes to access the side screws to get the speedo out I assumed I had disturbed some loose wire behind there when I noticed the light had stopped working. After disconnecting and reconnecting everything I could find there...nothing. A quick look at the fuse box and I spotted that a purple wire had made a break for freedom! It's always the last thing you try innit?
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Re: Voltage stabiliser/temperature gauge problem

Post by JOWETTJAVELIN »

Thanks for the follow-up, not everyone bothers, glad you got it sorted.
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