Smiths tacho in Volvo Amazon

The Volvo 123GT was the first Amazon with a tacho (see the genuine 1968 Volvo 123GT brochure I got with the car :-)). Back in the late sixties this 52 mm revolution counter became an accessory for the Volvo 122S.

Genuine Volvo 123GT sales brochure 1968 (cover)

Genuine Volvo 123GT sales brochure 1968  page 2 + 3 with
 Smiths Volvo revolution counter RVI 5411/00A

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Original  accessory revolution counter in Volvo Amazon

The original 123GT Smiths Volvo tacho (RVI 5411/00A) has an orange needle, chrome bezel and a 7000 rpm dial scaled from 10-70 (x100), the accessory Smiths Volvo tacho (RVI 5413/00) has a white needle, matte silver/grey bezel and is scaled 1-7 (x1000). In the genuine Volvo accessories catalogue, Volvo placed a picture of the GT model which wasn't the one you could buy as an  accessory. Both of these rev counters are hard to find nowadays.

Genuine Volvo accessories catalogue

The letter RVI on the Smiths tacho's indicates that it's a current impulse triggered tacho. You also have the newer  RVC (voltage triggered) Smiths tacho's. I've heard that if you put electronic ignition (eg 123) in your car your RVI tacho wouldn't work anymore... But if you change the wiring you could fix this problem: connect the tachometer with the two white wires in series between the 123ignition distributor ground wire and the ignition coil negative. That should solve the problem.

A couple of weeks ago I found a nice 60's/70's revolution counter on Internet.  This one (RVI 5414/00A) has the same shape but doesn't have the Volvo brand on the dial.

Smiths tacho  RVI 5414/00A

Smiths tacho  RVI 5414/00A with 8000 rpm dial

Smiths tacho  RVI 5414/00A inside

In order to install the tacho I had to drill a 12mm hole in my dashboard, all the way trough the metal. It's a bit hard to drill a vertical hole from the top with the windscreen in the car so I drilled a very small hole with a small battery drill from the top to mark the position and drilled the big hole from underneath the dashboard.

The rev counter has 5 wires:

1. white/red = light
2. black = ground
3. white = coil
4. white with green label = distributor 
5. white with red label = power

How to wire the RVI tacho

Before you start connecting all the wires, disconnect the battery! Make sure you completely remove the (black) original wire between the coil and distributor. Keep in mind that, when your tacho (wiring) is broken, you cannot start your car. If the rpm counter is acting funny swap the wires from the coil and distributor.

Smiths tacho  RVI 5414/00A

Smiths rpm counter  on top of dashpad

Smiths tacho  RVI 5414/00A in Volvo 122S 1969

After a couple of hours the tacho was installed and everything worked like it should be.

There's only one little thing and that's the white light in the Smiths rpm counter...  this was originally a green light like the rest of the dashboard lights. But that's easy to fix.

White tacho light - green dashboard lights