Tachometre/rev counter signal wire on early cars.

[Rick-Manta]

On the early Bs and Cavs without the 6 clock dash, is there still a signal wire for a rev counter or will I have to wire something from the coil or dizzy please?

It's an early 1977 Cavalier 1.9GL and I'm leaving the original clocks to retain originality and mileage, but want to add one of those little (period correct) tachometres that can mount on the steering column cover. Thanks.

[Snowy]

27 minutes ago, Rick-Manta said:

On the early Bs and Cavs without the 6 clock dash, is there still a signal wire for a rev counter or will I have to wire something from the coil or dizzy please?

It's an early 1977 Cavalier 1.9GL and I'm leaving the original clocks to retain originality and mileage, but want to add one of those little (period correct) tachometres that can mount on the steering column cover. Thanks.

None I've ever done have the plug behind the dash. Which makes sense as the round plug for the standard dash has a different pin out to the six clock dash.

 

[Rick-Manta]

Thanks. That's a shame, as I hoped they all had the same wiring loom and it would be an easy fit.

[cam.in.head]

as snowy says the pinout is different anyway so you cant just plug in a different dash .not sure why they did it that way ,you would think it would be easier to have one wiring loom as standard for all cars but i suppose it saved on a few lengths of wire .

if you fit an aftermarket tach that uses a negative trigger like the original then its just a case of running a single wire through to the coil green wire ( you could use a black wire to be easier to hide if you dont want to wrap it into the loom)

and then obviously a ignition fed live and an earth to run the tach.

if you ever fancy changing to a 6 dial dash its just a case of relocating the dash plug pins into their correct locations and then adding an extra plug and an oil pressure sender and one more wire.

[Snowy]

I even have a wiring guide for the change from standard to six clock dash.

[Rick-Manta]

Cheers guys. Yes, I'm just looking to fit a subtle tachometre rather than swap the clocks. Good idea on using a black wire. Once the car arrives, I'll see how feasible it will be to add it routed to the existing loom and recover it.

I quite like the hidden wiring look some classics have (where I assume the loom is lengthened and run thorough chassis rails and underneath the components) but I might be getting carried away there!