Voltage stabilizer

[f.swaans]

For my Marina based roadster with Smith gauges, (speedo, tacho, oil pressure, water temp, volt, amp and fuel meter is it necessary to use a voltage stabilizer?
The Marina wiring diagram shows one, but what is the function of it?
When it is necessary, where can I buy one?
Had it to be an universal one or specially BL part?


Kindly regards,
Frans Swaans

[stevejgreen]

Re: Voltage stabilizer

Stabiliser is usually mounted on the back of the smiths speedo. It provides a stable voltage to the Fuel sender and the temperature gauge only and will give more stable readings.
It can be replaced with ebay Item number: 280333716101 but occasionally the correct item will turn up but many from other vehicles will do the job.

[silver-back]

Re: Voltage stabilizer

triumph dolomite had one mounted to bulk head easy to get dont forget to earth the body though or it wont work

[andy4]

Re: Voltage stabilizer

I swapped from Marina instruments to a set from an MG - the Marina has a voltage regulator in the instruments itself. To buy a separate "original" regulator costs £20-25 and they won't be that good as they are mechanical. Instead if you can solder take a trip to maplins and get a LM317 solid state regulator and a couple of resistors and build your own - http://home.comcast.net/~whaussmann/InstrStabilizer/Instr_Stabilizer.htm is a good example - I just built mine into a cheap plastic case again from maplins and mounted in the dash.

[f.swaans]

Re: Voltage stabilizer

Amgas,
is 10V output the correct output?

[andy4]

Re: Voltage stabilizer

I believe 10v is correct for MGB instruments, so I guess most smiths type instrumnets will be the same - I think it is lower because of the design of the mechanical regulator - There is a great reference about this in a book called "MGB Electrical Systems" - if you go to books.google.co.uk and search for "MGB Electrical Systems instrument voltage regulator" then you can read the pages relating to the iustrument voltage regulator. This is actually a really good book and although it is written with an MGB bias I suspect a lot of it carries over to most british classic cars.

[h_m_cumming]

Re: Voltage stabilizer

The Smiths type are nominally 7.2V but they actually switch the 12V on and off to give a squarewave averageing 7.2V

[donsayers]

Re: Voltage stabilizer

I built a voltage regulator using solid state regulator, soldered to a small pcb with Lucar connectors soldered on. I didn’t put in a box but used an aluminium bracket as a heat sink and mounted it on the back of the speedo as per the original. The total cost was less than 50p.

I am using Smiths instruments (ex Spitfire) and 10 volts. All the gauges work just as they did with the original regulator. (With the usual caveat about the petrol gauge)

I can find no references to Smiths instruments working at 7.2v and plenty of references to them working at 10V.

Don

[donsayers]

Re: Voltage stabilizer

Good info here: http://www.minimaniauk.co.uk/web/DisplayID/2142/SCatagory/ELECTRICAL/DisplayType/Technical%20Information/ArticleV.cfm