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MG MGB Technical - replacing RVI/2401/00B tacho with RVI/2430/00


replacing RVI/2401/00B with RVI/2430/00

Hi,

I am looking to replace the positive earth tacho (RVI/2401/00B) in my 1967 MGB GT with a slightly later negative earth unit (RVI/2430/00) after changing the polarity of the car.

This website gives the detail on the back of the two units:

http://www.mgb-stuff.org.uk/tach.htm

does anyone know what is to be done with the loop of wire on the external sensor of the positive earth unit when wiring in the later unit?

do you cut the loop and plug it onto two (bullet and spade) terminals?

Any advice much appreciated

Cheers,

Cameron
C R Craigie

Yes, cut the loop and use the appropriate connectors for the tach. However you will need to know which half of the loop comes from the ignition switch and which goes to the coil so that you can get them on the right terminals on the back of the tach. The first part is easy - simply cut the loop and test the two ends with a meter or test-lamp looking for 12v, and that is the wire from the ignition switch. If you have the tach with the male and female bullets on the back of the case then I'd hazard a guess that the male bullet on the case is for the wire from the ignition, as originally the wire for that would have had a moulded-on insulated female so it wouldn't shirt to anything if it came off. If you have the tach with the two short wires ending in bullets then you will have to experiment, it won't do any harm getting them the wrong way round, but again I'd hazard a guess that the wire on the right in the photo on that site goes to the ignition, and the other one goes to the coil.
PaulH Solihull

This thread was discussed between 01/08/2011 and 02/08/2011

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