Wiring a tachometer

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david painter
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Re: Wiring a tachometer

Post by david painter » Fri Dec 07, 2018 7:39 am

You should locate the wire in the original harness and splice into that. Its current sensing so if you fit a additional wire the coil will only draw half of the current down the wire you will have to disconnect the original if you do put in a extra wire. I would 14/0.30mm strand wire this will carry 8.75 amp
Dave

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btorvestad
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Re: Wiring a tachometer

Post by btorvestad » Tue Oct 29, 2019 7:14 pm

Hello folks. It took me a very long time to get back on this one since I ended up with a pretty big job on restoring and upgrading my Marina in the meantime.

I wired it in series on the white wire from ignition to coil as described in this thread (and I also tried the opposite) but the tacho seems to be dead.

Any advice if there is anything to do to make it work? My car has original ignition.


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david painter
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Re: Wiring a tachometer

Post by david painter » Tue Oct 29, 2019 7:43 pm

So to Confirm you have wired as followed from ignition switch out to revcounter then from revcounter to ignition coil positive removing the original white wire so the current flows through revcounter
Dave

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btorvestad
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Re: Wiring a tachometer

Post by btorvestad » Tue Oct 29, 2019 10:07 pm

Yep, correct. Also confirmed by the fact that the car would not run when one of the wires were disconnected.


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david painter
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Re: Wiring a tachometer

Post by david painter » Wed Oct 30, 2019 7:25 am

It would suggest to me the rev counter itself is faulty
Dave

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btorvestad
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Re: Wiring a tachometer

Post by btorvestad » Wed Oct 30, 2019 5:48 pm

That’s what I was afraid of:(


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david painter
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Re: Wiring a tachometer

Post by david painter » Thu Oct 31, 2019 7:37 am

I recently had a RVC rev counter, in a MGC rebuilt and converted to modern RVI type by Speedy Cables. As we fitted a Pertonix Ignition to it stopping the old RVC unit from functioning https://speedycables.com › Instrument & Gauge Services
Dave

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locost_bryan
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Re: Wiring a tachometer

Post by locost_bryan » Thu Oct 31, 2019 10:05 pm

Hmm, I've got a spare rev counter, will have to find out if anyone local can do that conversion. Will have to ask the CFI people if their mappable electronic distributor can drive both types of rev counter.

Useful reference on Smiths rev counters here.
Bryan
Auckland NZ

1972 Morris Marina 1750 TC Coupe "Ozzy"

david painter
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Re: Wiring a tachometer

Post by david painter » Fri Nov 01, 2019 7:49 am

Very interesting PDF
Dave

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btorvestad
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Re: Wiring a tachometer

Post by btorvestad » Sat Apr 25, 2020 5:59 pm

Hey folks, picking up this thread again. I assumed my tacho was faulty but have now tried another one and still no action. Any other ideas? I have tried both polarities. Do I need to ground it or something?

Any suggestions welcome:)


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