tachometer questions/how to install

Post by **flowersGTR** » Fri Jul 10, 2009 3:01 pm

ive looked around the forum but i cant find a thread that really gives the info i need.
i have a 1970 mk3 MG midget rev counter that id like to put in my Minor, but unfortunatly i have no idea which connector is meant to connect to where.
here are a few pics

any help would be appreciated

lastly a quick question how would i wire in a switch to stop the fuel pump from working so as to act as a basic anti theft device?
im guesing theres a certain wire to the fuel pump which i would need to cut and place it in the middle

cheers

Post by **8009STEVE** » Fri Jul 10, 2009 3:54 pm

P.M. sent

Post by **nigelr2000** » Fri Jul 10, 2009 5:42 pm

I had a rev counter I fitted on my old cortina many years ago. As far as I remember the spade (Lucar) goes to 12 volts and the two Bullets (male and female) form part of a loop from the points to the coil connector so it can sense when it fires and generate the engine speed from that ( if it dont read reverse the connetions on the bullets). My one had negative earth written on the face but it was a ford one it also was for a 6 pot engine so read low but impressed me mates in the mid seventies when more gauges meant faster performance !!!!!!

Post by **flowersGTR** » Sat Jul 11, 2009 5:37 pm

thanks for the advice guys
does the 12v have to come from voltage smoother/stabaliser/regulator? or just from the fuse box?
cheers

Post by **Alec** » Sat Jul 11, 2009 6:00 pm

Hello FlowersGTR,

standard fused ignition fed supply, green cable, do not connect it to the voltage stabiliser.

Alec

Sat Jul 11, 2009 6:21 pm

Why not connect to the voltage stabiliser?

My rev counter drops about 1000 revs when i flash someone.. wouldn't going through the stabiliser help?

I fitted a TIM one to a car a while back and that did not go via the stabiliser.

so I am asking a question more than making a statement..

Post by **PSL184** » Sat Jul 11, 2009 7:58 pm

It is actually a voltage regulator, not a stabiliser, and as such gives out a regulated 10 volts - If the gauge needs 12 volts it won't work correctly....

Post by **bmcecosse** » Sat Jul 11, 2009 11:16 pm

But it's not a steady 10 volts - it jumps bout as the bi-metal strip opens and closes - giving an 'average' of 10 volts, which the fuel gauge doesn't worry about since it is a 'hot wire' instrument and so doesn't react to the small voltage changes - it's happy with the average! If you connected a sensitive instrument to that supply - it would jump about in response to the voltage variations.

Post by **flowersGTR** » Sat Sep 05, 2009 2:31 pm

cheers guys, i got the tacho working and have also installed a oil presure gauge as well,
i have the tacho coming from the fused ignition but now everytime i indicate the needle will move with the indicator, it appears to drop down when the indicators flash, any idea what that could be??
the rev counter also does not rev above about 3500 rpm, it stops there and wobbles a bit
could it be damaged?
cheers