MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Using 12v pump on a 6v system

I've got a pile of Minor and Spridget 12v fuel pumps but ideally need a 6v one to run a vintage car. Does anyone understand electrickery enough to tell me if a 12v pump can be modded to run happily on 6v? Alternatively, does anyone have a 6v pump to sell? I believe the original 6v ones had brown caps instead of black ones.
Thanks.

Confused, of Cardiff.
r thomas

Measure the resistance of the pump and solder a resistor of equal resistance to the pump in series with it?

In theory it would work... dunno if would just overheat the resistor though.

No idea what the resistance of the pump would be either and whether you would be able to get a resistor of the correct value.

Malcolm.
M Le Chevalier


in series?, then it would be 3v drop.

mog

Rob,

How well, if at all, does a 12V pump work on 6V. IIRC the solenoid pulls the diaphragm back against a spring and it is the spring return that pumps the fuel.
David Billington

Have I remembered my A-level physics incorrectly Mog? Sorry.

Malcolm
M Le Chevalier

Here's one...

http://www.ebay.co.uk/itm/Vintage-6-volts-S-U-fuel-pump-Low-pressure-AUA-26-Morris-8-1933-47-etc-etc-/311316064863
Dave O'Neill 2

could try a 6v to 12v inverter
http://www.ebay.co.uk/itm/Power-Inverter-6v-12v-Positive-Ground-/230889674275?_trksid=p2054897.l4275
mark 1500 on the road Preston Lancs

Sorry Malcolm, didnt mean it to sound curt.
mog

Try a farm and tractor repair shop...alot of the old massy fergusons, IH, and fords from the 50s and 60s used 6 volt systems
Prop and the Blackhole Midget

Hey Mog, wasn't offended or anything, just confused as to why it would only be 3V drop and hoped you would explain.

I thought it worked like this:

+12V ----> PUMP (say 10 ohm) ----> Resistor (10 ohm) ----> 0V

The resistors are the same, so 6 volt drop across the pump and 6 volt drop across the resistor.

Cheers,
Malcolm
M Le Chevalier

Malcolm,
The pump may be 12V, but the supply is 6V, presumably from a dynamo. If you share half and half between resistor and pump resistance, thats 3V each.

I've upped the whole system voltage on old Lucas dynamo equipped (E3L) bikes using fancy modern regulators. Bikes benefit from better lights, and better bulb availability. Ignition system is by magneto, so unaffected.
For a car, I suppose there's the ignition coil to take in to consideration, but there'd be 12 volts for your pump. Thats assuming the dynamo windings are up to it and you haven't already sorted out a standard voltage regulator of course.

All probably no help at all. Have you tried www.burlen.co.uk? They do overhaul kits etc. There might be an upgrade available.

Mark
M Crossley

ooooooooh!

so I clearly didn't listen in A level physics... yeah the bit when they told me "read the question properly". doh! what a div!

trying to get a 12v pump working on 6v system, not a 6v pump on a 12v system.

:-)
M Le Chevalier

Yeah ... Come on malc, get your head in the game. I cant belive you screwed that up,

Im telling ya, its a good thing for us old farts, keeping these youngens in line

Malc... id think 3 more apologies are in order for your sin of inaccuracy

Bad malc Bad !

Prop

Prop and the Blackhole Midget

lol
mog

I haven't got a 6v pump to sell, but I do have a recording of the 'funky chicken'.

http://www.youtube.com/watch?v=sFVrOW8TnJM

Rock it Rufus. :).




Lawrence Slater

This thread was discussed between 15/03/2015 and 16/03/2015

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.