Help, How to connect a Smiths tacho for Rover V8?

[Speer]

Hi guys, hope someone can help me.

I have a Smiths tacho that I'm using for a Rover v8 with opus 35DE8 ignition.
The tacho has 2 white wires and 1 green. How do i connect them?
I think 1 of the 3 wires goes to the white/black wire coming from the ballast resistor, but which of the 3? and where do the other 2 wire go?

Hope someone can help me

Speer (Netherlands)

[KevinW]

answers here

Electronic Tachometer

hth!

[Speer]

Hi Kevin, I had a look, this link seems to be for programmable tacho's, mine 's is not that fancy, it's an old tacho with just 3 wires.

Speer

[RCCob]

Hi Speer it is the same as mine by the sounds of it. Take a look at the yellow sticker on the back of my tacko it shows how to wire it. Hope this helps

Russ

[Purple AK]

If it's got two white wires it "could" be an early inductive type! In which case the whites form a loop that is the ign feed to the coil. Also be aware that it could be + earth so might need modifying for normal - earth. Best to speak with Caerbont to clarify Standard Instruments

[Speer]

Russ, it's different then the one I have (see picture). The white wires used to be in a loop from the - on the coil looping back to the ballast resistor (similar to what chris suggested). Think the green line is a switched feed.
I changed the wiring on the ignition (gave me problems, no spark) to follow the Rover manual. Engine runs now, but what to do with the tacho connections?
Any thoughts?

tacho.jpg