[Mgs] Fuel Gauge Calibration

[Paul Hunt]

The important thing with the later fuel gauge is to calibrate it to match 
the sender you have. Having changed senders twice on two cars I found that 
the first two, possibly replacing originals, were very different and both 
gauges needed recalibrating.  Of the 2nd two the one was OK but the other 
needed further recalibrating.

If you look on the back of the gauge there should be two holes with slotted 
plates in them, possibly covered by cork plugs.  Basically you twist the 
slotted plates to separately adjust the F (the slot closest to the F)  and E 
(ditto) readings.  Care is needed to use a tool that fills the slot as the 
plates are only thin, they can be quite stiff to turn, and it is easy to 
'round them out' if the screwdriver blade is too small.  Only a fraction of 
a turn is necessary, they are 'multi-turn'.  Adjust the F first by filling 
the tank, that's the easy bit.  Then run the tank down low in normal 
driving, and be aware that the gauge needle may stop moving some way before 
the tank runs out.  In my experience there is then something between a 
gallon and half a gallon left, but it will vary.  For the last bit siphon or 
use the pump to fill a container, listening to the pump all the while. Don't 
drive to run it out or the pump will be chattering for quite a long time 
before the float chambers empty and the engine stops, which won't do the 
pump any good.  Personally I then put a gallon back in, and only then 
adjusted the gauge to E, to give me a gallon 'reserve'.

More info and photos here: http://www.mgb-stuff.org.uk/wn_electricsframe.htm
and click on 'Gauges' then scroll down to 'Calibrating the gauge'.

PaulH.


----- Original Message ----- 
From: "Ron Fine" <RonFineEsq at earthlink.net>
To: "MG List" <mgs at autox.team.net>
Sent: Saturday, December 22, 2007 12:07 AM
Subject: [Mgs] Fuel Gauge Calibration


>I am looking for information on how to calibrate the fuel gauge on my '66 
>MGB.
> I am very familiar with the MGAGURU.COM web site and I used the 
> information
> there to successfully calibrate a fuel gauge on my Healey but the gauge in 
> the
> later MGB is of a different design.  There is a bimetal heated arm that 
> bends
> in response to current through the sending unit to ground and there are 
> two
> adjustment available to the mountings of the bimetal strip and the 
> tensioning
> spring but I don't know the current to use to make the adjustments.  Is 
> there
> some place I can look to find the resistance reading for the sending unit 
> for
> E, 1/2 and F ??
>
> Thanks,
> Ron
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