thebearded1:

Do you realize this thread is 11 years old? Unfortunately just about all of the contributors to the thread no longer visit this message board.
However, someone might still be able to help.

MAcEwen, Were you ever able to hook up the tach and get it working? I was recently given the same tach and was going to try and use it and came across this old thread trying to find wiring instructions.  I'm still wondering how you change it between 4, 6 and 8 cylinders too

My advice, go to the eBay link, read over, and write down the wiring as it applies to your car (presumably negative ground).  Look at that wiring information and identify which two wires ar exclusively for the illumination.  Connect power to them first to confirm that the lamp works.  The two white wires you know go to the coil & distributor.  That leaves you the two power wires and they should match the color codes listed in the eBay and Volvo links.

Great guys... this is exactly what I was hoping for.  I just need to figure out exactly which wire to do this with and I'll be laughing!!!  (or crying...)

More to follow, for sure, when I actually get to it... but I appreciate all the info provided so far.  Thanks for taking the time to sit and type it all out!

Rich

Good clarification Doug, somewhat (vaguely) what i was trying to say but you explained it a lot better with your electrical Mini knowledge which is second to none.

Just a point of clarification...
Which side of a fuse to connect to does not depend on whether the ignition is on or off.  You need to look for which circuits are "live" when the ignition switch is on.

To identify which circuit to use, take your multimeter and measure the voltage between each fuse and ground. 
Make these voltage measurements with the ignition off.  Write your voltage measurements down. 
Turn the ignition on and repeat your tests.  Again, write your voltage measurements down.
A fuse that has no voltage with the ignition off, and has 12V when the ignition is on is what you want.

Once you have identified a fused circuit to tap into, remove the fuse from the fuse box and turn the ignition on.
With the ignition on, measure the voltage between each side of the empty fuse holder and ground.
Connect your accessory to the side of the fuse holder that has NO voltage with the ignition on (and the fuse removed).
After connecting your accessory, replace the fuse in the fuse holder.

This will connect your accessory to a switched circuit on the protected side of the fuse.  Of course... if that fuse blows for some other reason, your accessory will lose power also.

Mac you need to run the power wire from the switched side of the fuse box it is the side that lights up with a test light or meter when you turn the ignition switch on, connected to the other side you would have power all the time and you don't want that.

I did some additional searching and only found one more applicable link. However, I think when you compare the two links I found, they identify the wiring for your tach.

From a Volvo blog
//123gt.blogspot.com/2008/06/on-volvos.html
RVI 5411/OOA MADE IN U.K. - NEGATIVE EARTH
There are 5 wires: 2 white wires (to the distributor and the coil low voltage terminal),
2 red (one to the headlight switch for illumination and one to the fuse box for 12V when the ignition is on)
and one black wire for ground.

From the eBay auction instructions (for negative ground)...
//www.ebay.com/itm/Rare-Smiths-Pedestal-Tachometer-Smiths-12-volt-60mm-Impulse-Tachometer-1969-/330783338381?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item4d04392f8d#ht_500wt_1287
RVI 5000/00A
Illuminatin:  Red with white stripe
Ground Wires: Green & Black
Power Supply Wire: Red
White with Red: Distributor side of Coil
White with Black: Distributor


How the eBay tach differs from the Volvo tach:
The Volvo tach was designed for negative ground and it appears that its case is conected to the black wire.
Therefore, there are only 5 wires instead of 6 as found on the eBay tach.
Apart from that and the question of the "2" red wires on the Volvo tach, the wiring is pretty much the same.

Based on this, I would follow the wiring as called out in the eBay auction. The color codes will be quite different than what we said earlier. Sorry.

I did some additional checking.  The 5000 series RVI (what you have) was primarily an aftermarket tach but apparently it was a somewhat common add-on for Volvos.  Inside that housing you may find that you have jumper wires to select 4-6-8 cylinders.  You may also find that the electronics are isolated from the case so you can use it for either positive or negative ground.  Therefore... disregard most of what we told you above... except for the white wires.

I am still looking for more information.  However, your best bet might be to write the seller in the eBay auction linked below and beg him to fax or scan and email a copy of the instructions for the tach he has for sale.  If you are patient you can look at his tach pictures which include partial copies of the instructions.  You may get enough information from his pictures that you don't even need to contact him/her.

//www.ebay.com/itm/Rare-Smiths-Pedestal-Tachometer-Smiths-12-volt-60mm-Impulse-Tachometer-1969-/330783338381?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item4d04392f8d#ht_500wt_1287

 

 

 

I have an older version. However I'm missing the white wire. I was told I can use a 16 gage wire to replace it. Here's a pic of the back

More confusion.  I opened the pod up and took the tach out to have a look.  It seems that you guys are right (though I never doubted).  The white wires are sense, purple (black) seems to be ground.

This is where it gets confusing.  It would appear that the green wire (the shortest of all) is soldered to a sort of elec board closest to where the light would mount, and the red is soldered else where on that board, but I can't tell where that solder leads too.  I thought of taking a picture, but I would have had to further dismantle it to do that... yikes.

So does any of this make sense?  As I said the green is shortest and its end seems still factory soldered, so I'm wondering if this is indeed the illum wire?  The red is long enough to go well into the engine bay.

So the lesson continues I guess...

So i can run the green wire from the tach to the fuse box, which fuse?  Is the gnition not fused anyway, making your orig idea (going to the switch) the same?  As i said, "electrically challenged"... Just wrapping my brain around it... 

Basically yes. You might want to connect to the fuse box so it is fused.

Thanks this helps alot.  So the power comes from the ignition circuit?

The red wire splices into the panel light wires somewhere which are red with a white tracer. What I do is solder on a bullet pludg and then find a double bullet connector. The black wire goes to a ground point. Solder on a ring connector and attach it to a steering bracket bolt. The green wire goes to a switch terminal on the ignition switch. You can figure out which one it is using a volt meter or test light by turning the key on and testing the 3 terminala or by figuring it out from a wiring diagram. Usually there is a spare enused spade there but you might need a double connector generally available from auto parts stores. Something like this.

//www.alibaba.com/product-gs/260663678/csel_terminal.html

Doug;

Ok so this all makes more sense.  As far as the guage is concerned it appears that it was never used, as the wires are still soldered on the ends.  I believe the "purple" wire is supposed to be black, just faded over 40 years!

So lets presume that the white wires go on the coil and dist... i had a look at the Mini and can see where I need to do that bit...  as far as the others are concerned (green red black).  If we assume that its not modified exactly where am I attaching the power, grnd and light??  I presume I pick a fuse in the box?

Cupcake; that pod on ebay is basically what I have and sadly i paid much much more!

Thanks all so far...

 

The RVI tach is "current sensing"...ie: it goes INLINE, like a flow sensor for water.

I am not sure if Doug covered this in his reply or not I ( blush, ) did not actually read it (red face)

So, if someone tells you to hook it up like all (ok, most) other tachs out there, you likely promptly smoke it.

I have the same (or very similar) tach in my car and had to replace a couple components to get it to work.

IIRC, mine came out of a late 60's or early 70's MGB (purportedly)

. . . .now I will go back and read Dougs post.

Whites are the trigger wires .... one goes to the negative post on the coil and the other goes to the spade terminal on the distributer. Take the back off the case and check the other wires. I'm guessing the red is for the light  and the others will a power wire and a ground. You'll see which is the ground wire when you take the back off.

If anybody else is interested in one of these there's one on Ebay right now that's a good deal so far.

//www.ebay.com/itm/Rare-Smiths-Pedestal-Tachometer-Smiths-12-volt-60mm-Impulse-Tachometer-1969-/330783338381?pt=Motorcycles_Parts_Accessories&hash=item4d04392f8d&vxp=mtr

I had one on my Traveller but it was too small IMHO and I replaced it with a full-sized Smiths tach.

The wire colors may or not mean anything and if you want to safely install this tach, take it out of the pod and look at where the wires connect to the gauge.  Previous owners may have changed things.  Also, you need to look for clues about whether this is a positive or negative ground tach.  So, out of the case first.

The link below is one online source to look at regarding the basic wiring.
//www.speedycables.com/page34aaaa.html\
Do not put a lot of faith in the color codes in the link above.  The model shown in the link has the external inductive loop of wire.  Your tach may not have the external loop. It may have the loop inside the case.

When you remove the tach from the pod, first look for which wires are used for illumination, mark them and check them off your list.  The gauge may use one or two wires for illumination depending on whether or not the bulb is grounded to the pod.

The white wires hopefully still mean what Smiths intended them to be, the sense wires for the tach.  If they are, the two wires will enter the tach housing immediately adjacent to each other and/or be looped on the back of the gauge.  As a sanity check, use your multimeter to check for continuity/resistance between the ends of the two white wires.  If you measure Zero ohms from one white wire to the other, you have located the sense wires. 

The remaining wires will be for power (ground and switched, fused 12V).  Hopefully the terminals on the back of the gauge will identify which is which.  If NOT, you have to assume that the original Smiths wire color codes apply.  That would be... black = ground, green = +12V, and red = illumination.  This is different from what you will find on modern tachometers by brands other than Smiths.  I am not familiar with Smiths using a purple wire as shown on your gauge so again... take the gauge out of the pod to see if you can figure out what it is for.

Assuming you have correctly identified and connected the power and illumination wires, that leaves the white wires.  Since your Mini did not leave the factory with the tach or wiring to support it I'll give the easiest suggestion.  Run the two white wires into the engine bay and over towards the coil and distributor.  You will find a wire going from coil the coil to the distributor.  Typically that wire is white/black.  Disconnect that wire at the coil and at the distributor.  Connect one tach white wire to the coil where you removed the white/black wire.  Connect the other tach white wire to the distributor where you disconnected the other end of the white/black wire. 

Start the engine.  If the tach misbehaves or reads "funny", switch off the ignition and swap where you connected the two white wires.  Try again.  If the tach still misbehaves but otherwise works, you have other issues to deal with than the wiring. 

Keep in mind that very few RVI tachs will work with electronic ignitions. Consider these only suitable for points ignitions.  Remember that these RVI type gauges are 40+ years old and may not work at all.