What is this

[Rockape]

Just rebuilding the car after the speedo problem - wanted to start the engine before I replace all the instrument lights and refit the dash. 
 

what is this gizmo attached to the back of the speedo? Do I need to connect the wires back before reconnecting the battery?

[RedRooster]

Voltage stabiliser, yes it needs to be connected. 

[johny]

Yes powers your temperature and fuel gauges...

[dougbgt6]

It supplies voltage for fuel gauge and temperature gauge, drops 12v to 9.5v. If it fails you get incorrect gauge readings, but yes, sure, you can try the engine without it. It's electro mechanical, a lot replace it with an electronic one.

Doug

[Pete Lewis]

and it relies on the speedo having a good earth

this is a spit III   some spits its on the baulkhead behind the glove box 

only used with slow needle moving thermo bimetal gauges 

note the word "top" its important 

Pete   

 

[Rockape]

Thanks all. Will wire it all up then and give it a go !

[johny]

Its even adjustable (although its not recommended to fiddle) - take that modern electronic gizmos!

[JohnD]

Adjustable???  How, please?

[johny]

Theres a little screw there that adjusts the thermal mechanism inside so changes the opening closing rate of the contacts so gives a higher or lower average voltage output, neat😁

[Peter Truman]

4 hours ago, Pete Lewis said:

 

note the word "top" its important 

Pete   

 

Never noticed TOP on my spares so why is it important the VR is a bi-metallic strip so how does its orientation affect its operation, Pete? On my cars it'll only mount one way anyway.

[johny]

Maybe gravity affects it and as calibrated one way it has to be used in that same position?

[Pete Lewis]

some have top on the body (as in the pic )   some it is stamped in the paxolin terminal plate 

no idea why , but as said most will only fit the right way up

its there to even out the varying voltages of the charge otherwise gauges would give varying readings 

some electronic droppers just drop they dont all control to a fixed pulsed  voltage 

Pete

[Rockape]

Sorry about the “top” label - it’s mine

i marked everything up and took photos as I dismantled the dashboard….

[johny]

Petes right though they quite often have top marked on them by the manufacturer👍

[johny]

Must admit changed mine for an ebay electronic jobbee and they can go in any way up😁

[dougbgt6]

I have an electronic one, solid state, it just dangles. I do not recommend "adjusting" the electro mechanical, you would be  "mending to destruction", much the same as the Stromberg temperature adjusters.

Doug

[johny]

Spoil sport Doug!

[Colin Lindsay]

5 hours ago, dougbgt6 said:

I have an electronic one, solid state, it just dangles.

Sign of age, that. On that 'other' forum electronic things usually replace the dangly things.